[PATCH OLK-6.6 V2 00/18] cachefiles: introduce failover mechanism
V2: add subsequent bugfix patches and some clean up. V1: adapt mainline patch for main function Baokun Li (11): cachefiles: add output string to cachefiles_obj_[get|put]_ondemand_fd cachefiles: remove requests from xarray during flushing requests cachefiles: fix slab-use-after-free in cachefiles_ondemand_get_fd() cachefiles: fix slab-use-after-free in cachefiles_ondemand_daemon_read() cachefiles: remove err_put_fd label in cachefiles_ondemand_daemon_read() cachefiles: add consistency check for copen/cread cachefiles: add spin_lock for cachefiles_ondemand_info cachefiles: never get a new anonymous fd if ondemand_id is valid cachefiles: defer exposing anon_fd until after copy_to_user() succeeds cachefiles: flush all requests after setting CACHEFILES_DEAD cachefiles: make on-demand read killable David Howells (1): cachefiles, erofs: Fix NULL deref in when cachefiles is not doing ondemand-mode Jia Zhu (5): cachefiles: introduce object ondemand state cachefiles: extract ondemand info field from cachefiles_object cachefiles: resend an open request if the read request's object is closed cachefiles: narrow the scope of triggering EPOLLIN events in ondemand mode cachefiles: add restore command to recover inflight ondemand read requests Zizhi Wo (1): cachefiles: Set object to close if ondemand_id < 0 in copen fs/cachefiles/daemon.c | 18 +- fs/cachefiles/interface.c | 7 +- fs/cachefiles/internal.h | 64 ++++- fs/cachefiles/ondemand.c | 372 ++++++++++++++++++++++-------- include/trace/events/cachefiles.h | 8 +- 5 files changed, 373 insertions(+), 96 deletions(-) -- 2.39.2
From: Jia Zhu <zhujia.zj@bytedance.com> mainline inclusion from mainline-v6.8-rc1 commit 357a18d033143617e9c7d420c8f0dd4cbab5f34d category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Previously, @ondemand_id field was used not only to identify ondemand state of the object, but also to represent the index of the xarray. This commit introduces @state field to decouple the role of @ondemand_id and adds helpers to access it. Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com> Link: https://lore.kernel.org/r/20231120041422.75170-2-zhujia.zj@bytedance.com Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: David Howells <dhowells@redhat.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/internal.h | 21 +++++++++++++++++++++ fs/cachefiles/ondemand.c | 21 +++++++++------------ 2 files changed, 30 insertions(+), 12 deletions(-) diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index 2ad58c465208..00beedeaec18 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -44,6 +44,11 @@ struct cachefiles_volume { struct dentry *fanout[256]; /* Fanout subdirs */ }; +enum cachefiles_object_state { + CACHEFILES_ONDEMAND_OBJSTATE_CLOSE, /* Anonymous fd closed by daemon or initial state */ + CACHEFILES_ONDEMAND_OBJSTATE_OPEN, /* Anonymous fd associated with object is available */ +}; + /* * Backing file state. */ @@ -62,6 +67,7 @@ struct cachefiles_object { #define CACHEFILES_OBJECT_USING_TMPFILE 0 /* Have an unlinked tmpfile */ #ifdef CONFIG_CACHEFILES_ONDEMAND int ondemand_id; + enum cachefiles_object_state state; #endif }; @@ -296,6 +302,21 @@ extern void cachefiles_ondemand_clean_object(struct cachefiles_object *object); extern int cachefiles_ondemand_read(struct cachefiles_object *object, loff_t pos, size_t len); +#define CACHEFILES_OBJECT_STATE_FUNCS(_state, _STATE) \ +static inline bool \ +cachefiles_ondemand_object_is_##_state(const struct cachefiles_object *object) \ +{ \ + return object->state == CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \ +} \ + \ +static inline void \ +cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \ +{ \ + object->state = CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \ +} + +CACHEFILES_OBJECT_STATE_FUNCS(open, OPEN); +CACHEFILES_OBJECT_STATE_FUNCS(close, CLOSE); #else static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, char __user *_buffer, size_t buflen) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index 0254ed39f68c..90456b8a4b3e 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -15,6 +15,7 @@ static int cachefiles_ondemand_fd_release(struct inode *inode, xa_lock(&cache->reqs); object->ondemand_id = CACHEFILES_ONDEMAND_ID_CLOSED; + cachefiles_ondemand_set_object_close(object); /* * Flush all pending READ requests since their completion depends on @@ -176,6 +177,8 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags); trace_cachefiles_ondemand_copen(req->object, id, size); + cachefiles_ondemand_set_object_open(req->object); + out: complete(&req->done); return ret; @@ -363,7 +366,8 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object, /* coupled with the barrier in cachefiles_flush_reqs() */ smp_mb(); - if (opcode != CACHEFILES_OP_OPEN && object->ondemand_id <= 0) { + if (opcode != CACHEFILES_OP_OPEN && + !cachefiles_ondemand_object_is_open(object)) { WARN_ON_ONCE(object->ondemand_id == 0); xas_unlock(&xas); ret = -EIO; @@ -430,18 +434,11 @@ static int cachefiles_ondemand_init_close_req(struct cachefiles_req *req, void *private) { struct cachefiles_object *object = req->object; - int object_id = object->ondemand_id; - /* - * It's possible that object id is still 0 if the cookie looking up - * phase failed before OPEN request has ever been sent. Also avoid - * sending CLOSE request for CACHEFILES_ONDEMAND_ID_CLOSED, which means - * anon_fd has already been closed. - */ - if (object_id <= 0) + if (!cachefiles_ondemand_object_is_open(object)) return -ENOENT; - req->msg.object_id = object_id; + req->msg.object_id = object->ondemand_id; trace_cachefiles_ondemand_close(object, &req->msg); return 0; } @@ -460,7 +457,7 @@ static int cachefiles_ondemand_init_read_req(struct cachefiles_req *req, int object_id = object->ondemand_id; /* Stop enqueuing requests when daemon has closed anon_fd. */ - if (object_id <= 0) { + if (!cachefiles_ondemand_object_is_open(object)) { WARN_ON_ONCE(object_id == 0); pr_info_once("READ: anonymous fd closed prematurely.\n"); return -EIO; @@ -485,7 +482,7 @@ int cachefiles_ondemand_init_object(struct cachefiles_object *object) * creating a new tmpfile as the cache file. Reuse the previously * allocated object ID if any. */ - if (object->ondemand_id > 0) + if (cachefiles_ondemand_object_is_open(object)) return 0; volume_key_size = volume->key[0] + 1; -- 2.39.2
From: Jia Zhu <zhujia.zj@bytedance.com> mainline inclusion from mainline-v6.8-rc1 commit 3c5ecfe16e7699011c12c2d44e55437415331fa3 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- We'll introduce a @work_struct field for @object in subsequent patches, it will enlarge the size of @object. As the result of that, this commit extracts ondemand info field from @object. Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com> Link: https://lore.kernel.org/r/20231120041422.75170-3-zhujia.zj@bytedance.com Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: David Howells <dhowells@redhat.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/interface.c | 7 ++++++- fs/cachefiles/internal.h | 26 ++++++++++++++++++++++---- fs/cachefiles/ondemand.c | 34 ++++++++++++++++++++++++++++------ 3 files changed, 56 insertions(+), 11 deletions(-) diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c index 40052bdb3365..35ba2117a6f6 100644 --- a/fs/cachefiles/interface.c +++ b/fs/cachefiles/interface.c @@ -31,6 +31,11 @@ struct cachefiles_object *cachefiles_alloc_object(struct fscache_cookie *cookie) if (!object) return NULL; + if (cachefiles_ondemand_init_obj_info(object, volume)) { + kmem_cache_free(cachefiles_object_jar, object); + return NULL; + } + refcount_set(&object->ref, 1); spin_lock_init(&object->lock); @@ -88,7 +93,7 @@ void cachefiles_put_object(struct cachefiles_object *object, ASSERTCMP(object->file, ==, NULL); kfree(object->d_name); - + cachefiles_ondemand_deinit_obj_info(object); cache = object->volume->cache->cache; fscache_put_cookie(object->cookie, fscache_cookie_put_object); object->cookie = NULL; diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index 00beedeaec18..b0fe76964bc0 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -49,6 +49,12 @@ enum cachefiles_object_state { CACHEFILES_ONDEMAND_OBJSTATE_OPEN, /* Anonymous fd associated with object is available */ }; +struct cachefiles_ondemand_info { + int ondemand_id; + enum cachefiles_object_state state; + struct cachefiles_object *object; +}; + /* * Backing file state. */ @@ -66,8 +72,7 @@ struct cachefiles_object { unsigned long flags; #define CACHEFILES_OBJECT_USING_TMPFILE 0 /* Have an unlinked tmpfile */ #ifdef CONFIG_CACHEFILES_ONDEMAND - int ondemand_id; - enum cachefiles_object_state state; + struct cachefiles_ondemand_info *ondemand; #endif }; @@ -302,17 +307,21 @@ extern void cachefiles_ondemand_clean_object(struct cachefiles_object *object); extern int cachefiles_ondemand_read(struct cachefiles_object *object, loff_t pos, size_t len); +extern int cachefiles_ondemand_init_obj_info(struct cachefiles_object *obj, + struct cachefiles_volume *volume); +extern void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj); + #define CACHEFILES_OBJECT_STATE_FUNCS(_state, _STATE) \ static inline bool \ cachefiles_ondemand_object_is_##_state(const struct cachefiles_object *object) \ { \ - return object->state == CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \ + return object->ondemand->state == CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \ } \ \ static inline void \ cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \ { \ - object->state = CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \ + object->ondemand->state = CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \ } CACHEFILES_OBJECT_STATE_FUNCS(open, OPEN); @@ -338,6 +347,15 @@ static inline int cachefiles_ondemand_read(struct cachefiles_object *object, { return -EOPNOTSUPP; } + +static inline int cachefiles_ondemand_init_obj_info(struct cachefiles_object *obj, + struct cachefiles_volume *volume) +{ + return 0; +} +static inline void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj) +{ +} #endif /* diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index 90456b8a4b3e..deb7e3007aa1 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -9,12 +9,13 @@ static int cachefiles_ondemand_fd_release(struct inode *inode, { struct cachefiles_object *object = file->private_data; struct cachefiles_cache *cache = object->volume->cache; - int object_id = object->ondemand_id; + struct cachefiles_ondemand_info *info = object->ondemand; + int object_id = info->ondemand_id; struct cachefiles_req *req; XA_STATE(xas, &cache->reqs, 0); xa_lock(&cache->reqs); - object->ondemand_id = CACHEFILES_ONDEMAND_ID_CLOSED; + info->ondemand_id = CACHEFILES_ONDEMAND_ID_CLOSED; cachefiles_ondemand_set_object_close(object); /* @@ -222,7 +223,7 @@ static int cachefiles_ondemand_get_fd(struct cachefiles_req *req) load = (void *)req->msg.data; load->fd = fd; req->msg.object_id = object_id; - object->ondemand_id = object_id; + object->ondemand->ondemand_id = object_id; cachefiles_get_unbind_pincount(cache); trace_cachefiles_ondemand_open(object, &req->msg, load); @@ -368,7 +369,7 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object, if (opcode != CACHEFILES_OP_OPEN && !cachefiles_ondemand_object_is_open(object)) { - WARN_ON_ONCE(object->ondemand_id == 0); + WARN_ON_ONCE(object->ondemand->ondemand_id == 0); xas_unlock(&xas); ret = -EIO; goto out; @@ -438,7 +439,7 @@ static int cachefiles_ondemand_init_close_req(struct cachefiles_req *req, if (!cachefiles_ondemand_object_is_open(object)) return -ENOENT; - req->msg.object_id = object->ondemand_id; + req->msg.object_id = object->ondemand->ondemand_id; trace_cachefiles_ondemand_close(object, &req->msg); return 0; } @@ -454,7 +455,7 @@ static int cachefiles_ondemand_init_read_req(struct cachefiles_req *req, struct cachefiles_object *object = req->object; struct cachefiles_read *load = (void *)req->msg.data; struct cachefiles_read_ctx *read_ctx = private; - int object_id = object->ondemand_id; + int object_id = object->ondemand->ondemand_id; /* Stop enqueuing requests when daemon has closed anon_fd. */ if (!cachefiles_ondemand_object_is_open(object)) { @@ -500,6 +501,27 @@ void cachefiles_ondemand_clean_object(struct cachefiles_object *object) cachefiles_ondemand_init_close_req, NULL); } +int cachefiles_ondemand_init_obj_info(struct cachefiles_object *object, + struct cachefiles_volume *volume) +{ + if (!cachefiles_in_ondemand_mode(volume->cache)) + return 0; + + object->ondemand = kzalloc(sizeof(struct cachefiles_ondemand_info), + GFP_KERNEL); + if (!object->ondemand) + return -ENOMEM; + + object->ondemand->object = object; + return 0; +} + +void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *object) +{ + kfree(object->ondemand); + object->ondemand = NULL; +} + int cachefiles_ondemand_read(struct cachefiles_object *object, loff_t pos, size_t len) { -- 2.39.2
From: Jia Zhu <zhujia.zj@bytedance.com> mainline inclusion from mainline-v6.8-rc1 commit 0a7e54c1959c0feb2de23397ec09c7692364313e category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- When an anonymous fd is closed by user daemon, if there is a new read request for this file comes up, the anonymous fd should be re-opened to handle that read request rather than fail it directly. 1. Introduce reopening state for objects that are closed but have inflight/subsequent read requests. 2. No longer flush READ requests but only CLOSE requests when anonymous fd is closed. 3. Enqueue the reopen work to workqueue, thus user daemon could get rid of daemon_read context and handle that request smoothly. Otherwise, the user daemon will send a reopen request and wait for itself to process the request. Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com> Link: https://lore.kernel.org/r/20231120041422.75170-4-zhujia.zj@bytedance.com Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: David Howells <dhowells@redhat.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/internal.h | 3 ++ fs/cachefiles/ondemand.c | 98 ++++++++++++++++++++++++++++------------ 2 files changed, 72 insertions(+), 29 deletions(-) diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index b0fe76964bc0..b9a90f1a0c01 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -47,9 +47,11 @@ struct cachefiles_volume { enum cachefiles_object_state { CACHEFILES_ONDEMAND_OBJSTATE_CLOSE, /* Anonymous fd closed by daemon or initial state */ CACHEFILES_ONDEMAND_OBJSTATE_OPEN, /* Anonymous fd associated with object is available */ + CACHEFILES_ONDEMAND_OBJSTATE_REOPENING, /* Object that was closed and is being reopened. */ }; struct cachefiles_ondemand_info { + struct work_struct ondemand_work; int ondemand_id; enum cachefiles_object_state state; struct cachefiles_object *object; @@ -326,6 +328,7 @@ cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \ CACHEFILES_OBJECT_STATE_FUNCS(open, OPEN); CACHEFILES_OBJECT_STATE_FUNCS(close, CLOSE); +CACHEFILES_OBJECT_STATE_FUNCS(reopening, REOPENING); #else static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, char __user *_buffer, size_t buflen) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index deb7e3007aa1..8e130de952f7 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -18,14 +18,10 @@ static int cachefiles_ondemand_fd_release(struct inode *inode, info->ondemand_id = CACHEFILES_ONDEMAND_ID_CLOSED; cachefiles_ondemand_set_object_close(object); - /* - * Flush all pending READ requests since their completion depends on - * anon_fd. - */ - xas_for_each(&xas, req, ULONG_MAX) { + /* Only flush CACHEFILES_REQ_NEW marked req to avoid race with daemon_read */ + xas_for_each_marked(&xas, req, ULONG_MAX, CACHEFILES_REQ_NEW) { if (req->msg.object_id == object_id && - req->msg.opcode == CACHEFILES_OP_READ) { - req->error = -EIO; + req->msg.opcode == CACHEFILES_OP_CLOSE) { complete(&req->done); xas_store(&xas, NULL); } @@ -179,6 +175,7 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) trace_cachefiles_ondemand_copen(req->object, id, size); cachefiles_ondemand_set_object_open(req->object); + wake_up_all(&cache->daemon_pollwq); out: complete(&req->done); @@ -222,7 +219,6 @@ static int cachefiles_ondemand_get_fd(struct cachefiles_req *req) load = (void *)req->msg.data; load->fd = fd; - req->msg.object_id = object_id; object->ondemand->ondemand_id = object_id; cachefiles_get_unbind_pincount(cache); @@ -238,6 +234,43 @@ static int cachefiles_ondemand_get_fd(struct cachefiles_req *req) return ret; } +static void ondemand_object_worker(struct work_struct *work) +{ + struct cachefiles_ondemand_info *info = + container_of(work, struct cachefiles_ondemand_info, ondemand_work); + + cachefiles_ondemand_init_object(info->object); +} + +/* + * If there are any inflight or subsequent READ requests on the + * closed object, reopen it. + * Skip read requests whose related object is reopening. + */ +static struct cachefiles_req *cachefiles_ondemand_select_req(struct xa_state *xas, + unsigned long xa_max) +{ + struct cachefiles_req *req; + struct cachefiles_object *object; + struct cachefiles_ondemand_info *info; + + xas_for_each_marked(xas, req, xa_max, CACHEFILES_REQ_NEW) { + if (req->msg.opcode != CACHEFILES_OP_READ) + return req; + object = req->object; + info = object->ondemand; + if (cachefiles_ondemand_object_is_close(object)) { + cachefiles_ondemand_set_object_reopening(object); + queue_work(fscache_wq, &info->ondemand_work); + continue; + } + if (cachefiles_ondemand_object_is_reopening(object)) + continue; + return req; + } + return NULL; +} + ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, char __user *_buffer, size_t buflen) { @@ -248,16 +281,16 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, int ret = 0; XA_STATE(xas, &cache->reqs, cache->req_id_next); + xa_lock(&cache->reqs); /* * Cyclically search for a request that has not ever been processed, * to prevent requests from being processed repeatedly, and make * request distribution fair. */ - xa_lock(&cache->reqs); - req = xas_find_marked(&xas, UINT_MAX, CACHEFILES_REQ_NEW); + req = cachefiles_ondemand_select_req(&xas, ULONG_MAX); if (!req && cache->req_id_next > 0) { xas_set(&xas, 0); - req = xas_find_marked(&xas, cache->req_id_next - 1, CACHEFILES_REQ_NEW); + req = cachefiles_ondemand_select_req(&xas, cache->req_id_next - 1); } if (!req) { xa_unlock(&cache->reqs); @@ -277,14 +310,18 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, xa_unlock(&cache->reqs); id = xas.xa_index; - msg->msg_id = id; if (msg->opcode == CACHEFILES_OP_OPEN) { ret = cachefiles_ondemand_get_fd(req); - if (ret) + if (ret) { + cachefiles_ondemand_set_object_close(req->object); goto error; + } } + msg->msg_id = id; + msg->object_id = req->object->ondemand->ondemand_id; + if (copy_to_user(_buffer, msg, n) != 0) { ret = -EFAULT; goto err_put_fd; @@ -317,19 +354,23 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object, void *private) { struct cachefiles_cache *cache = object->volume->cache; - struct cachefiles_req *req; + struct cachefiles_req *req = NULL; XA_STATE(xas, &cache->reqs, 0); int ret; if (!test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags)) return 0; - if (test_bit(CACHEFILES_DEAD, &cache->flags)) - return -EIO; + if (test_bit(CACHEFILES_DEAD, &cache->flags)) { + ret = -EIO; + goto out; + } req = kzalloc(sizeof(*req) + data_len, GFP_KERNEL); - if (!req) - return -ENOMEM; + if (!req) { + ret = -ENOMEM; + goto out; + } req->object = object; init_completion(&req->done); @@ -367,7 +408,7 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object, /* coupled with the barrier in cachefiles_flush_reqs() */ smp_mb(); - if (opcode != CACHEFILES_OP_OPEN && + if (opcode == CACHEFILES_OP_CLOSE && !cachefiles_ondemand_object_is_open(object)) { WARN_ON_ONCE(object->ondemand->ondemand_id == 0); xas_unlock(&xas); @@ -392,7 +433,15 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object, wake_up_all(&cache->daemon_pollwq); wait_for_completion(&req->done); ret = req->error; + kfree(req); + return ret; out: + /* Reset the object to close state in error handling path. + * If error occurs after creating the anonymous fd, + * cachefiles_ondemand_fd_release() will set object to close. + */ + if (opcode == CACHEFILES_OP_OPEN) + cachefiles_ondemand_set_object_close(object); kfree(req); return ret; } @@ -439,7 +488,6 @@ static int cachefiles_ondemand_init_close_req(struct cachefiles_req *req, if (!cachefiles_ondemand_object_is_open(object)) return -ENOENT; - req->msg.object_id = object->ondemand->ondemand_id; trace_cachefiles_ondemand_close(object, &req->msg); return 0; } @@ -455,16 +503,7 @@ static int cachefiles_ondemand_init_read_req(struct cachefiles_req *req, struct cachefiles_object *object = req->object; struct cachefiles_read *load = (void *)req->msg.data; struct cachefiles_read_ctx *read_ctx = private; - int object_id = object->ondemand->ondemand_id; - - /* Stop enqueuing requests when daemon has closed anon_fd. */ - if (!cachefiles_ondemand_object_is_open(object)) { - WARN_ON_ONCE(object_id == 0); - pr_info_once("READ: anonymous fd closed prematurely.\n"); - return -EIO; - } - req->msg.object_id = object_id; load->off = read_ctx->off; load->len = read_ctx->len; trace_cachefiles_ondemand_read(object, &req->msg, load); @@ -513,6 +552,7 @@ int cachefiles_ondemand_init_obj_info(struct cachefiles_object *object, return -ENOMEM; object->ondemand->object = object; + INIT_WORK(&object->ondemand->ondemand_work, ondemand_object_worker); return 0; } -- 2.39.2
From: Jia Zhu <zhujia.zj@bytedance.com> mainline inclusion from mainline-v6.8-rc1 commit b817e22b2e91257ace32a6768c3c003faeaa1c5c category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Don't trigger EPOLLIN when there are only reopening read requests in xarray. Suggested-by: Xin Yin <yinxin.x@bytedance.com> Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com> Link: https://lore.kernel.org/r/20231120041422.75170-5-zhujia.zj@bytedance.com Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: David Howells <dhowells@redhat.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/daemon.c | 14 ++++++++++++-- fs/cachefiles/internal.h | 12 ++++++++++++ 2 files changed, 24 insertions(+), 2 deletions(-) diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c index 5f4df9588620..4611fcfb8182 100644 --- a/fs/cachefiles/daemon.c +++ b/fs/cachefiles/daemon.c @@ -355,14 +355,24 @@ static __poll_t cachefiles_daemon_poll(struct file *file, struct poll_table_struct *poll) { struct cachefiles_cache *cache = file->private_data; + XA_STATE(xas, &cache->reqs, 0); + struct cachefiles_req *req; __poll_t mask; poll_wait(file, &cache->daemon_pollwq, poll); mask = 0; if (cachefiles_in_ondemand_mode(cache)) { - if (!xa_empty(&cache->reqs)) - mask |= EPOLLIN; + if (!xa_empty(&cache->reqs)) { + rcu_read_lock(); + xas_for_each_marked(&xas, req, ULONG_MAX, CACHEFILES_REQ_NEW) { + if (!cachefiles_ondemand_is_reopening_read(req)) { + mask |= EPOLLIN; + break; + } + } + rcu_read_unlock(); + } } else { if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags)) mask |= EPOLLIN; diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index b9a90f1a0c01..26e5f8f123ef 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -329,6 +329,13 @@ cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \ CACHEFILES_OBJECT_STATE_FUNCS(open, OPEN); CACHEFILES_OBJECT_STATE_FUNCS(close, CLOSE); CACHEFILES_OBJECT_STATE_FUNCS(reopening, REOPENING); + +static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req *req) +{ + return cachefiles_ondemand_object_is_reopening(req->object) && + req->msg.opcode == CACHEFILES_OP_READ; +} + #else static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, char __user *_buffer, size_t buflen) @@ -359,6 +366,11 @@ static inline int cachefiles_ondemand_init_obj_info(struct cachefiles_object *ob static inline void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj) { } + +static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req *req) +{ + return false; +} #endif /* -- 2.39.2
From: Jia Zhu <zhujia.zj@bytedance.com> mainline inclusion from mainline-v6.8-rc1 commit e73fa11a356ca0905c3cc648eaacc6f0f2d2c8b3 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Previously, in ondemand read scenario, if the anonymous fd was closed by user daemon, inflight and subsequent read requests would return EIO. As long as the device connection is not released, user daemon can hold and restore inflight requests by setting the request flag to CACHEFILES_REQ_NEW. Suggested-by: Gao Xiang <hsiangkao@linux.alibaba.com> Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com> Signed-off-by: Xin Yin <yinxin.x@bytedance.com> Link: https://lore.kernel.org/r/20231120041422.75170-6-zhujia.zj@bytedance.com Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: David Howells <dhowells@redhat.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/daemon.c | 1 + fs/cachefiles/internal.h | 3 +++ fs/cachefiles/ondemand.c | 23 +++++++++++++++++++++++ 3 files changed, 27 insertions(+) diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c index 4611fcfb8182..6465e2574230 100644 --- a/fs/cachefiles/daemon.c +++ b/fs/cachefiles/daemon.c @@ -77,6 +77,7 @@ static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = { { "tag", cachefiles_daemon_tag }, #ifdef CONFIG_CACHEFILES_ONDEMAND { "copen", cachefiles_ondemand_copen }, + { "restore", cachefiles_ondemand_restore }, #endif { "", NULL } }; diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index 26e5f8f123ef..4a87c9d714a9 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -303,6 +303,9 @@ extern ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, extern int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args); +extern int cachefiles_ondemand_restore(struct cachefiles_cache *cache, + char *args); + extern int cachefiles_ondemand_init_object(struct cachefiles_object *object); extern void cachefiles_ondemand_clean_object(struct cachefiles_object *object); diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index 8e130de952f7..b8fbbb1961bb 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -182,6 +182,29 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) return ret; } +int cachefiles_ondemand_restore(struct cachefiles_cache *cache, char *args) +{ + struct cachefiles_req *req; + + XA_STATE(xas, &cache->reqs, 0); + + if (!test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags)) + return -EOPNOTSUPP; + + /* + * Reset the requests to CACHEFILES_REQ_NEW state, so that the + * requests have been processed halfway before the crash of the + * user daemon could be reprocessed after the recovery. + */ + xas_lock(&xas); + xas_for_each(&xas, req, ULONG_MAX) + xas_set_mark(&xas, CACHEFILES_REQ_NEW); + xas_unlock(&xas); + + wake_up_all(&cache->daemon_pollwq); + return 0; +} + static int cachefiles_ondemand_get_fd(struct cachefiles_req *req) { struct cachefiles_object *object; -- 2.39.2
From: David Howells <dhowells@redhat.com> mainline inclusion from mainline-v6.8-rc2 commit c3d6569a43322f371e7ba0ad386112723757ac8f category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- cachefiles_ondemand_init_object() as called from cachefiles_open_file() and cachefiles_create_tmpfile() does not check if object->ondemand is set before dereferencing it, leading to an oops something like: RIP: 0010:cachefiles_ondemand_init_object+0x9/0x41 ... Call Trace: <TASK> cachefiles_open_file+0xc9/0x187 cachefiles_lookup_cookie+0x122/0x2be fscache_cookie_state_machine+0xbe/0x32b fscache_cookie_worker+0x1f/0x2d process_one_work+0x136/0x208 process_scheduled_works+0x3a/0x41 worker_thread+0x1a2/0x1f6 kthread+0xca/0xd2 ret_from_fork+0x21/0x33 Fix this by making cachefiles_ondemand_init_object() return immediately if cachefiles->ondemand is NULL. Fixes: 3c5ecfe16e76 ("cachefiles: extract ondemand info field from cachefiles_object") Reported-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: Gao Xiang <xiang@kernel.org> cc: Chao Yu <chao@kernel.org> cc: Yue Hu <huyue2@coolpad.com> cc: Jeffle Xu <jefflexu@linux.alibaba.com> cc: linux-erofs@lists.ozlabs.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/ondemand.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index b8fbbb1961bb..c15f2547222e 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -539,6 +539,9 @@ int cachefiles_ondemand_init_object(struct cachefiles_object *object) struct fscache_volume *volume = object->volume->vcookie; size_t volume_key_size, cookie_key_size, data_len; + if (!object->ondemand) + return 0; + /* * CacheFiles will firstly check the cache file under the root cache * directory. If the coherency check failed, it will fallback to -- 2.39.2
From: Baokun Li <libaokun1@huawei.com> mainline inclusion from mainline-v6.10-rc4 commit cc5ac966f26193ab185cc43d64d9f1ae998ccb6e category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- This lets us see the correct trace output. Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie") Signed-off-by: Baokun Li <libaokun1@huawei.com> Link: https://lore.kernel.org/r/20240522114308.2402121-2-libaokun@huaweicloud.com Acked-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- include/trace/events/cachefiles.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/include/trace/events/cachefiles.h b/include/trace/events/cachefiles.h index cf4b98b9a9ed..e3213af847cd 100644 --- a/include/trace/events/cachefiles.h +++ b/include/trace/events/cachefiles.h @@ -127,7 +127,9 @@ enum cachefiles_error_trace { EM(cachefiles_obj_see_lookup_cookie, "SEE lookup_cookie") \ EM(cachefiles_obj_see_lookup_failed, "SEE lookup_failed") \ EM(cachefiles_obj_see_withdraw_cookie, "SEE withdraw_cookie") \ - E_(cachefiles_obj_see_withdrawal, "SEE withdrawal") + EM(cachefiles_obj_see_withdrawal, "SEE withdrawal") \ + EM(cachefiles_obj_get_ondemand_fd, "GET ondemand_fd") \ + E_(cachefiles_obj_put_ondemand_fd, "PUT ondemand_fd") #define cachefiles_coherency_traces \ EM(cachefiles_coherency_check_aux, "BAD aux ") \ -- 2.39.2
From: Baokun Li <libaokun1@huawei.com> mainline inclusion from mainline-v6.10-rc4 commit 0fc75c5940fa634d84e64c93bfc388e1274ed013 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Even with CACHEFILES_DEAD set, we can still read the requests, so in the following concurrency the request may be used after it has been freed: mount | daemon_thread1 | daemon_thread2 ------------------------------------------------------------ cachefiles_ondemand_init_object cachefiles_ondemand_send_req REQ_A = kzalloc(sizeof(*req) + data_len) wait_for_completion(&REQ_A->done) cachefiles_daemon_read cachefiles_ondemand_daemon_read // close dev fd cachefiles_flush_reqs complete(&REQ_A->done) kfree(REQ_A) xa_lock(&cache->reqs); cachefiles_ondemand_select_req req->msg.opcode != CACHEFILES_OP_READ // req use-after-free !!! xa_unlock(&cache->reqs); xa_destroy(&cache->reqs) Hence remove requests from cache->reqs when flushing them to avoid accessing freed requests. Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie") Signed-off-by: Baokun Li <libaokun1@huawei.com> Link: https://lore.kernel.org/r/20240522114308.2402121-3-libaokun@huaweicloud.com Acked-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/daemon.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c index 6465e2574230..ccb7b707ea4b 100644 --- a/fs/cachefiles/daemon.c +++ b/fs/cachefiles/daemon.c @@ -159,6 +159,7 @@ static void cachefiles_flush_reqs(struct cachefiles_cache *cache) xa_for_each(xa, index, req) { req->error = -EIO; complete(&req->done); + __xa_erase(xa, index); } xa_unlock(xa); -- 2.39.2
From: Baokun Li <libaokun1@huawei.com> mainline inclusion from mainline-v6.10-rc4 commit de3e26f9e5b76fc628077578c001c4a51bf54d06 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- We got the following issue in a fuzz test of randomly issuing the restore command: ================================================================== BUG: KASAN: slab-use-after-free in cachefiles_ondemand_daemon_read+0x609/0xab0 Write of size 4 at addr ffff888109164a80 by task ondemand-04-dae/4962 CPU: 11 PID: 4962 Comm: ondemand-04-dae Not tainted 6.8.0-rc7-dirty #542 Call Trace: kasan_report+0x94/0xc0 cachefiles_ondemand_daemon_read+0x609/0xab0 vfs_read+0x169/0xb50 ksys_read+0xf5/0x1e0 Allocated by task 626: __kmalloc+0x1df/0x4b0 cachefiles_ondemand_send_req+0x24d/0x690 cachefiles_create_tmpfile+0x249/0xb30 cachefiles_create_file+0x6f/0x140 cachefiles_look_up_object+0x29c/0xa60 cachefiles_lookup_cookie+0x37d/0xca0 fscache_cookie_state_machine+0x43c/0x1230 [...] Freed by task 626: kfree+0xf1/0x2c0 cachefiles_ondemand_send_req+0x568/0x690 cachefiles_create_tmpfile+0x249/0xb30 cachefiles_create_file+0x6f/0x140 cachefiles_look_up_object+0x29c/0xa60 cachefiles_lookup_cookie+0x37d/0xca0 fscache_cookie_state_machine+0x43c/0x1230 [...] ================================================================== Following is the process that triggers the issue: mount | daemon_thread1 | daemon_thread2 ------------------------------------------------------------ cachefiles_ondemand_init_object cachefiles_ondemand_send_req REQ_A = kzalloc(sizeof(*req) + data_len) wait_for_completion(&REQ_A->done) cachefiles_daemon_read cachefiles_ondemand_daemon_read REQ_A = cachefiles_ondemand_select_req cachefiles_ondemand_get_fd copy_to_user(_buffer, msg, n) process_open_req(REQ_A) ------ restore ------ cachefiles_ondemand_restore xas_for_each(&xas, req, ULONG_MAX) xas_set_mark(&xas, CACHEFILES_REQ_NEW); cachefiles_daemon_read cachefiles_ondemand_daemon_read REQ_A = cachefiles_ondemand_select_req write(devfd, ("copen %u,%llu", msg->msg_id, size)); cachefiles_ondemand_copen xa_erase(&cache->reqs, id) complete(&REQ_A->done) kfree(REQ_A) cachefiles_ondemand_get_fd(REQ_A) fd = get_unused_fd_flags file = anon_inode_getfile fd_install(fd, file) load = (void *)REQ_A->msg.data; load->fd = fd; // load UAF !!! This issue is caused by issuing a restore command when the daemon is still alive, which results in a request being processed multiple times thus triggering a UAF. So to avoid this problem, add an additional reference count to cachefiles_req, which is held while waiting and reading, and then released when the waiting and reading is over. Note that since there is only one reference count for waiting, we need to avoid the same request being completed multiple times, so we can only complete the request if it is successfully removed from the xarray. Fixes: e73fa11a356c ("cachefiles: add restore command to recover inflight ondemand read requests") Suggested-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Baokun Li <libaokun1@huawei.com> Link: https://lore.kernel.org/r/20240522114308.2402121-4-libaokun@huaweicloud.com Acked-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com> Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/internal.h | 1 + fs/cachefiles/ondemand.c | 23 +++++++++++++++++++---- 2 files changed, 20 insertions(+), 4 deletions(-) diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index 4a87c9d714a9..e3b7b240bf83 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -138,6 +138,7 @@ static inline bool cachefiles_in_ondemand_mode(struct cachefiles_cache *cache) struct cachefiles_req { struct cachefiles_object *object; struct completion done; + refcount_t ref; int error; struct cachefiles_msg msg; }; diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index c15f2547222e..f833b5d6ecb1 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -4,6 +4,12 @@ #include <linux/uio.h> #include "internal.h" +static inline void cachefiles_req_put(struct cachefiles_req *req) +{ + if (refcount_dec_and_test(&req->ref)) + kfree(req); +} + static int cachefiles_ondemand_fd_release(struct inode *inode, struct file *file) { @@ -330,6 +336,7 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, xas_clear_mark(&xas, CACHEFILES_REQ_NEW); cache->req_id_next = xas.xa_index + 1; + refcount_inc(&req->ref); xa_unlock(&cache->reqs); id = xas.xa_index; @@ -356,15 +363,22 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, complete(&req->done); } + cachefiles_req_put(req); return n; err_put_fd: if (msg->opcode == CACHEFILES_OP_OPEN) close_fd(((struct cachefiles_open *)msg->data)->fd); error: - xa_erase(&cache->reqs, id); - req->error = ret; - complete(&req->done); + xas_reset(&xas); + xas_lock(&xas); + if (xas_load(&xas) == req) { + req->error = ret; + complete(&req->done); + xas_store(&xas, NULL); + } + xas_unlock(&xas); + cachefiles_req_put(req); return ret; } @@ -395,6 +409,7 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object, goto out; } + refcount_set(&req->ref, 1); req->object = object; init_completion(&req->done); req->msg.opcode = opcode; @@ -456,7 +471,7 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object, wake_up_all(&cache->daemon_pollwq); wait_for_completion(&req->done); ret = req->error; - kfree(req); + cachefiles_req_put(req); return ret; out: /* Reset the object to close state in error handling path. -- 2.39.2
From: Baokun Li <libaokun1@huawei.com> mainline inclusion from mainline-v6.10-rc4 commit da4a827416066191aafeeccee50a8836a826ba10 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- We got the following issue in a fuzz test of randomly issuing the restore command: ================================================================== BUG: KASAN: slab-use-after-free in cachefiles_ondemand_daemon_read+0xb41/0xb60 Read of size 8 at addr ffff888122e84088 by task ondemand-04-dae/963 CPU: 13 PID: 963 Comm: ondemand-04-dae Not tainted 6.8.0-dirty #564 Call Trace: kasan_report+0x93/0xc0 cachefiles_ondemand_daemon_read+0xb41/0xb60 vfs_read+0x169/0xb50 ksys_read+0xf5/0x1e0 Allocated by task 116: kmem_cache_alloc+0x140/0x3a0 cachefiles_lookup_cookie+0x140/0xcd0 fscache_cookie_state_machine+0x43c/0x1230 [...] Freed by task 792: kmem_cache_free+0xfe/0x390 cachefiles_put_object+0x241/0x480 fscache_cookie_state_machine+0x5c8/0x1230 [...] ================================================================== Following is the process that triggers the issue: mount | daemon_thread1 | daemon_thread2 ------------------------------------------------------------ cachefiles_withdraw_cookie cachefiles_ondemand_clean_object(object) cachefiles_ondemand_send_req REQ_A = kzalloc(sizeof(*req) + data_len) wait_for_completion(&REQ_A->done) cachefiles_daemon_read cachefiles_ondemand_daemon_read REQ_A = cachefiles_ondemand_select_req msg->object_id = req->object->ondemand->ondemand_id ------ restore ------ cachefiles_ondemand_restore xas_for_each(&xas, req, ULONG_MAX) xas_set_mark(&xas, CACHEFILES_REQ_NEW) cachefiles_daemon_read cachefiles_ondemand_daemon_read REQ_A = cachefiles_ondemand_select_req copy_to_user(_buffer, msg, n) xa_erase(&cache->reqs, id) complete(&REQ_A->done) ------ close(fd) ------ cachefiles_ondemand_fd_release cachefiles_put_object cachefiles_put_object kmem_cache_free(cachefiles_object_jar, object) REQ_A->object->ondemand->ondemand_id // object UAF !!! When we see the request within xa_lock, req->object must not have been freed yet, so grab the reference count of object before xa_unlock to avoid the above issue. Fixes: 0a7e54c1959c ("cachefiles: resend an open request if the read request's object is closed") Signed-off-by: Baokun Li <libaokun1@huawei.com> Link: https://lore.kernel.org/r/20240522114308.2402121-5-libaokun@huaweicloud.com Acked-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com> Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/ondemand.c | 3 +++ include/trace/events/cachefiles.h | 6 +++++- 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index f833b5d6ecb1..188ac81d324f 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -337,6 +337,7 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, xas_clear_mark(&xas, CACHEFILES_REQ_NEW); cache->req_id_next = xas.xa_index + 1; refcount_inc(&req->ref); + cachefiles_grab_object(req->object, cachefiles_obj_get_read_req); xa_unlock(&cache->reqs); id = xas.xa_index; @@ -357,6 +358,7 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, goto err_put_fd; } + cachefiles_put_object(req->object, cachefiles_obj_put_read_req); /* CLOSE request has no reply */ if (msg->opcode == CACHEFILES_OP_CLOSE) { xa_erase(&cache->reqs, id); @@ -370,6 +372,7 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, if (msg->opcode == CACHEFILES_OP_OPEN) close_fd(((struct cachefiles_open *)msg->data)->fd); error: + cachefiles_put_object(req->object, cachefiles_obj_put_read_req); xas_reset(&xas); xas_lock(&xas); if (xas_load(&xas) == req) { diff --git a/include/trace/events/cachefiles.h b/include/trace/events/cachefiles.h index e3213af847cd..7d931db02b93 100644 --- a/include/trace/events/cachefiles.h +++ b/include/trace/events/cachefiles.h @@ -33,6 +33,8 @@ enum cachefiles_obj_ref_trace { cachefiles_obj_see_withdrawal, cachefiles_obj_get_ondemand_fd, cachefiles_obj_put_ondemand_fd, + cachefiles_obj_get_read_req, + cachefiles_obj_put_read_req, }; enum fscache_why_object_killed { @@ -129,7 +131,9 @@ enum cachefiles_error_trace { EM(cachefiles_obj_see_withdraw_cookie, "SEE withdraw_cookie") \ EM(cachefiles_obj_see_withdrawal, "SEE withdrawal") \ EM(cachefiles_obj_get_ondemand_fd, "GET ondemand_fd") \ - E_(cachefiles_obj_put_ondemand_fd, "PUT ondemand_fd") + EM(cachefiles_obj_put_ondemand_fd, "PUT ondemand_fd") \ + EM(cachefiles_obj_get_read_req, "GET read_req") \ + E_(cachefiles_obj_put_read_req, "PUT read_req") #define cachefiles_coherency_traces \ EM(cachefiles_coherency_check_aux, "BAD aux ") \ -- 2.39.2
From: Baokun Li <libaokun1@huawei.com> mainline inclusion from mainline-v6.10-rc4 commit 3e6d704f02aa4c50c7bc5fe91a4401df249a137b category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- The err_put_fd label is only used once, so remove it to make the code more readable. In addition, the logic for deleting error request and CLOSE request is merged to simplify the code. Signed-off-by: Baokun Li <libaokun1@huawei.com> Link: https://lore.kernel.org/r/20240522114308.2402121-6-libaokun@huaweicloud.com Acked-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/ondemand.c | 45 ++++++++++++++-------------------------- 1 file changed, 16 insertions(+), 29 deletions(-) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index 188ac81d324f..2f81a9c68693 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -305,7 +305,6 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, { struct cachefiles_req *req; struct cachefiles_msg *msg; - unsigned long id = 0; size_t n; int ret = 0; XA_STATE(xas, &cache->reqs, cache->req_id_next); @@ -340,49 +339,37 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, cachefiles_grab_object(req->object, cachefiles_obj_get_read_req); xa_unlock(&cache->reqs); - id = xas.xa_index; - if (msg->opcode == CACHEFILES_OP_OPEN) { ret = cachefiles_ondemand_get_fd(req); if (ret) { cachefiles_ondemand_set_object_close(req->object); - goto error; + goto out; } } - msg->msg_id = id; + msg->msg_id = xas.xa_index; msg->object_id = req->object->ondemand->ondemand_id; if (copy_to_user(_buffer, msg, n) != 0) { ret = -EFAULT; - goto err_put_fd; - } - - cachefiles_put_object(req->object, cachefiles_obj_put_read_req); - /* CLOSE request has no reply */ - if (msg->opcode == CACHEFILES_OP_CLOSE) { - xa_erase(&cache->reqs, id); - complete(&req->done); + if (msg->opcode == CACHEFILES_OP_OPEN) + close_fd(((struct cachefiles_open *)msg->data)->fd); } - - cachefiles_req_put(req); - return n; - -err_put_fd: - if (msg->opcode == CACHEFILES_OP_OPEN) - close_fd(((struct cachefiles_open *)msg->data)->fd); -error: +out: cachefiles_put_object(req->object, cachefiles_obj_put_read_req); - xas_reset(&xas); - xas_lock(&xas); - if (xas_load(&xas) == req) { - req->error = ret; - complete(&req->done); - xas_store(&xas, NULL); + /* Remove error request and CLOSE request has no reply */ + if (ret || msg->opcode == CACHEFILES_OP_CLOSE) { + xas_reset(&xas); + xas_lock(&xas); + if (xas_load(&xas) == req) { + req->error = ret; + complete(&req->done); + xas_store(&xas, NULL); + } + xas_unlock(&xas); } - xas_unlock(&xas); cachefiles_req_put(req); - return ret; + return ret ? ret : n; } typedef int (*init_req_fn)(struct cachefiles_req *req, void *private); -- 2.39.2
From: Baokun Li <libaokun1@huawei.com> mainline inclusion from mainline-v6.10-rc4 commit a26dc49df37e996876f50a0210039b2d211fdd6f category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- This prevents malicious processes from completing random copen/cread requests and crashing the system. Added checks are listed below: * Generic, copen can only complete open requests, and cread can only complete read requests. * For copen, ondemand_id must not be 0, because this indicates that the request has not been read by the daemon. * For cread, the object corresponding to fd and req should be the same. Signed-off-by: Baokun Li <libaokun1@huawei.com> Link: https://lore.kernel.org/r/20240522114308.2402121-7-libaokun@huaweicloud.com Acked-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/ondemand.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index 2f81a9c68693..e205ce6fd15d 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -82,12 +82,12 @@ static loff_t cachefiles_ondemand_fd_llseek(struct file *filp, loff_t pos, } static long cachefiles_ondemand_fd_ioctl(struct file *filp, unsigned int ioctl, - unsigned long arg) + unsigned long id) { struct cachefiles_object *object = filp->private_data; struct cachefiles_cache *cache = object->volume->cache; struct cachefiles_req *req; - unsigned long id; + XA_STATE(xas, &cache->reqs, id); if (ioctl != CACHEFILES_IOC_READ_COMPLETE) return -EINVAL; @@ -95,10 +95,15 @@ static long cachefiles_ondemand_fd_ioctl(struct file *filp, unsigned int ioctl, if (!test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags)) return -EOPNOTSUPP; - id = arg; - req = xa_erase(&cache->reqs, id); - if (!req) + xa_lock(&cache->reqs); + req = xas_load(&xas); + if (!req || req->msg.opcode != CACHEFILES_OP_READ || + req->object != object) { + xa_unlock(&cache->reqs); return -EINVAL; + } + xas_store(&xas, NULL); + xa_unlock(&cache->reqs); trace_cachefiles_ondemand_cread(object, id); complete(&req->done); @@ -126,6 +131,7 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) unsigned long id; long size; int ret; + XA_STATE(xas, &cache->reqs, 0); if (!test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags)) return -EOPNOTSUPP; @@ -149,9 +155,16 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) if (ret) return ret; - req = xa_erase(&cache->reqs, id); - if (!req) + xa_lock(&cache->reqs); + xas.xa_index = id; + req = xas_load(&xas); + if (!req || req->msg.opcode != CACHEFILES_OP_OPEN || + !req->object->ondemand->ondemand_id) { + xa_unlock(&cache->reqs); return -EINVAL; + } + xas_store(&xas, NULL); + xa_unlock(&cache->reqs); /* fail OPEN request if copen format is invalid */ ret = kstrtol(psize, 0, &size); -- 2.39.2
From: Baokun Li <libaokun1@huawei.com> mainline inclusion from mainline-v6.10-rc4 commit 0a790040838c736495d5afd6b2d636f159f817f1 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- The following concurrency may cause a read request to fail to be completed and result in a hung: t1 | t2 --------------------------------------------------------- cachefiles_ondemand_copen req = xa_erase(&cache->reqs, id) // Anon fd is maliciously closed. cachefiles_ondemand_fd_release xa_lock(&cache->reqs) cachefiles_ondemand_set_object_close(object) xa_unlock(&cache->reqs) cachefiles_ondemand_set_object_open // No one will ever close it again. cachefiles_ondemand_daemon_read cachefiles_ondemand_select_req // Get a read req but its fd is already closed. // The daemon can't issue a cread ioctl with an closed fd, then hung. So add spin_lock for cachefiles_ondemand_info to protect ondemand_id and state, thus we can avoid the above problem in cachefiles_ondemand_copen() by using ondemand_id to determine if fd has been closed. Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie") Signed-off-by: Baokun Li <libaokun1@huawei.com> Link: https://lore.kernel.org/r/20240522114308.2402121-8-libaokun@huaweicloud.com Acked-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/internal.h | 1 + fs/cachefiles/ondemand.c | 35 ++++++++++++++++++++++++++++++++++- 2 files changed, 35 insertions(+), 1 deletion(-) diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index e3b7b240bf83..67b4e729b40b 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -55,6 +55,7 @@ struct cachefiles_ondemand_info { int ondemand_id; enum cachefiles_object_state state; struct cachefiles_object *object; + spinlock_t lock; }; /* diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index e205ce6fd15d..2f66e1cbf17b 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -16,13 +16,16 @@ static int cachefiles_ondemand_fd_release(struct inode *inode, struct cachefiles_object *object = file->private_data; struct cachefiles_cache *cache = object->volume->cache; struct cachefiles_ondemand_info *info = object->ondemand; - int object_id = info->ondemand_id; + int object_id; struct cachefiles_req *req; XA_STATE(xas, &cache->reqs, 0); xa_lock(&cache->reqs); + spin_lock(&info->lock); + object_id = info->ondemand_id; info->ondemand_id = CACHEFILES_ONDEMAND_ID_CLOSED; cachefiles_ondemand_set_object_close(object); + spin_unlock(&info->lock); /* Only flush CACHEFILES_REQ_NEW marked req to avoid race with daemon_read */ xas_for_each_marked(&xas, req, ULONG_MAX, CACHEFILES_REQ_NEW) { @@ -127,6 +130,7 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) { struct cachefiles_req *req; struct fscache_cookie *cookie; + struct cachefiles_ondemand_info *info; char *pid, *psize; unsigned long id; long size; @@ -185,6 +189,33 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) goto out; } + info = req->object->ondemand; + spin_lock(&info->lock); + /* + * The anonymous fd was closed before copen ? Fail the request. + * + * t1 | t2 + * --------------------------------------------------------- + * cachefiles_ondemand_copen + * req = xa_erase(&cache->reqs, id) + * // Anon fd is maliciously closed. + * cachefiles_ondemand_fd_release + * xa_lock(&cache->reqs) + * cachefiles_ondemand_set_object_close(object) + * xa_unlock(&cache->reqs) + * cachefiles_ondemand_set_object_open + * // No one will ever close it again. + * cachefiles_ondemand_daemon_read + * cachefiles_ondemand_select_req + * + * Get a read req but its fd is already closed. The daemon can't + * issue a cread ioctl with an closed fd, then hung. + */ + if (info->ondemand_id == CACHEFILES_ONDEMAND_ID_CLOSED) { + spin_unlock(&info->lock); + req->error = -EBADFD; + goto out; + } cookie = req->object->cookie; cookie->object_size = size; if (size) @@ -194,6 +225,7 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) trace_cachefiles_ondemand_copen(req->object, id, size); cachefiles_ondemand_set_object_open(req->object); + spin_unlock(&info->lock); wake_up_all(&cache->daemon_pollwq); out: @@ -596,6 +628,7 @@ int cachefiles_ondemand_init_obj_info(struct cachefiles_object *object, return -ENOMEM; object->ondemand->object = object; + spin_lock_init(&object->ondemand->lock); INIT_WORK(&object->ondemand->ondemand_work, ondemand_object_worker); return 0; } -- 2.39.2
From: Baokun Li <libaokun1@huawei.com> mainline inclusion from mainline-v6.10-rc4 commit 4988e35e95fc938bdde0e15880fe72042fc86acf category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Now every time the daemon reads an open request, it gets a new anonymous fd and ondemand_id. With the introduction of "restore", it is possible to read the same open request more than once, and therefore an object can have more than one anonymous fd. If the anonymous fd is not unique, the following concurrencies will result in an fd leak: t1 | t2 | t3 ------------------------------------------------------------ cachefiles_ondemand_init_object cachefiles_ondemand_send_req REQ_A = kzalloc(sizeof(*req) + data_len) wait_for_completion(&REQ_A->done) cachefiles_daemon_read cachefiles_ondemand_daemon_read REQ_A = cachefiles_ondemand_select_req cachefiles_ondemand_get_fd load->fd = fd0 ondemand_id = object_id0 ------ restore ------ cachefiles_ondemand_restore // restore REQ_A cachefiles_daemon_read cachefiles_ondemand_daemon_read REQ_A = cachefiles_ondemand_select_req cachefiles_ondemand_get_fd load->fd = fd1 ondemand_id = object_id1 process_open_req(REQ_A) write(devfd, ("copen %u,%llu", msg->msg_id, size)) cachefiles_ondemand_copen xa_erase(&cache->reqs, id) complete(&REQ_A->done) kfree(REQ_A) process_open_req(REQ_A) // copen fails due to no req // daemon close(fd1) cachefiles_ondemand_fd_release // set object closed -- umount -- cachefiles_withdraw_cookie cachefiles_ondemand_clean_object cachefiles_ondemand_init_close_req if (!cachefiles_ondemand_object_is_open(object)) return -ENOENT; // The fd0 is not closed until the daemon exits. However, the anonymous fd holds the reference count of the object and the object holds the reference count of the cookie. So even though the cookie has been relinquished, it will not be unhashed and freed until the daemon exits. In fscache_hash_cookie(), when the same cookie is found in the hash list, if the cookie is set with the FSCACHE_COOKIE_RELINQUISHED bit, then the new cookie waits for the old cookie to be unhashed, while the old cookie is waiting for the leaked fd to be closed, if the daemon does not exit in time it will trigger a hung task. To avoid this, allocate a new anonymous fd only if no anonymous fd has been allocated (ondemand_id == 0) or if the previously allocated anonymous fd has been closed (ondemand_id == -1). Moreover, returns an error if ondemand_id is valid, letting the daemon know that the current userland restore logic is abnormal and needs to be checked. Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie") Signed-off-by: Baokun Li <libaokun1@huawei.com> Link: https://lore.kernel.org/r/20240522114308.2402121-9-libaokun@huaweicloud.com Acked-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/ondemand.c | 34 ++++++++++++++++++++++++++++------ 1 file changed, 28 insertions(+), 6 deletions(-) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index 2f66e1cbf17b..0464e329198a 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -14,11 +14,18 @@ static int cachefiles_ondemand_fd_release(struct inode *inode, struct file *file) { struct cachefiles_object *object = file->private_data; - struct cachefiles_cache *cache = object->volume->cache; - struct cachefiles_ondemand_info *info = object->ondemand; + struct cachefiles_cache *cache; + struct cachefiles_ondemand_info *info; int object_id; struct cachefiles_req *req; - XA_STATE(xas, &cache->reqs, 0); + XA_STATE(xas, NULL, 0); + + if (!object) + return 0; + + info = object->ondemand; + cache = object->volume->cache; + xas.xa = &cache->reqs; xa_lock(&cache->reqs); spin_lock(&info->lock); @@ -288,22 +295,39 @@ static int cachefiles_ondemand_get_fd(struct cachefiles_req *req) goto err_put_fd; } + spin_lock(&object->ondemand->lock); + if (object->ondemand->ondemand_id > 0) { + spin_unlock(&object->ondemand->lock); + /* Pair with check in cachefiles_ondemand_fd_release(). */ + file->private_data = NULL; + ret = -EEXIST; + goto err_put_file; + } + file->f_mode |= FMODE_PWRITE | FMODE_LSEEK; fd_install(fd, file); load = (void *)req->msg.data; load->fd = fd; object->ondemand->ondemand_id = object_id; + spin_unlock(&object->ondemand->lock); cachefiles_get_unbind_pincount(cache); trace_cachefiles_ondemand_open(object, &req->msg, load); return 0; +err_put_file: + fput(file); err_put_fd: put_unused_fd(fd); err_free_id: xa_erase(&cache->ondemand_ids, object_id); err: + spin_lock(&object->ondemand->lock); + /* Avoid marking an opened object as closed. */ + if (object->ondemand->ondemand_id <= 0) + cachefiles_ondemand_set_object_close(object); + spin_unlock(&object->ondemand->lock); cachefiles_put_object(object, cachefiles_obj_put_ondemand_fd); return ret; } @@ -386,10 +410,8 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, if (msg->opcode == CACHEFILES_OP_OPEN) { ret = cachefiles_ondemand_get_fd(req); - if (ret) { - cachefiles_ondemand_set_object_close(req->object); + if (ret) goto out; - } } msg->msg_id = xas.xa_index; -- 2.39.2
From: Baokun Li <libaokun1@huawei.com> mainline inclusion from mainline-v6.10-rc4 commit 4b4391e77a6bf24cba2ef1590e113d9b73b11039 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- After installing the anonymous fd, we can now see it in userland and close it. However, at this point we may not have gotten the reference count of the cache, but we will put it during colse fd, so this may cause a cache UAF. So grab the cache reference count before fd_install(). In addition, by kernel convention, fd is taken over by the user land after fd_install(), and the kernel should not call close_fd() after that, i.e., it should call fd_install() after everything is ready, thus fd_install() is called after copy_to_user() succeeds. Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie") Suggested-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Baokun Li <libaokun1@huawei.com> Link: https://lore.kernel.org/r/20240522114308.2402121-10-libaokun@huaweicloud.com Acked-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/ondemand.c | 53 +++++++++++++++++++++++++--------------- 1 file changed, 33 insertions(+), 20 deletions(-) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index 0464e329198a..b8e9cdc93643 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -4,6 +4,11 @@ #include <linux/uio.h> #include "internal.h" +struct ondemand_anon_file { + struct file *file; + int fd; +}; + static inline void cachefiles_req_put(struct cachefiles_req *req) { if (refcount_dec_and_test(&req->ref)) @@ -263,14 +268,14 @@ int cachefiles_ondemand_restore(struct cachefiles_cache *cache, char *args) return 0; } -static int cachefiles_ondemand_get_fd(struct cachefiles_req *req) +static int cachefiles_ondemand_get_fd(struct cachefiles_req *req, + struct ondemand_anon_file *anon_file) { struct cachefiles_object *object; struct cachefiles_cache *cache; struct cachefiles_open *load; - struct file *file; u32 object_id; - int ret, fd; + int ret; object = cachefiles_grab_object(req->object, cachefiles_obj_get_ondemand_fd); @@ -282,16 +287,16 @@ static int cachefiles_ondemand_get_fd(struct cachefiles_req *req) if (ret < 0) goto err; - fd = get_unused_fd_flags(O_WRONLY); - if (fd < 0) { - ret = fd; + anon_file->fd = get_unused_fd_flags(O_WRONLY); + if (anon_file->fd < 0) { + ret = anon_file->fd; goto err_free_id; } - file = anon_inode_getfile("[cachefiles]", &cachefiles_ondemand_fd_fops, - object, O_WRONLY); - if (IS_ERR(file)) { - ret = PTR_ERR(file); + anon_file->file = anon_inode_getfile("[cachefiles]", + &cachefiles_ondemand_fd_fops, object, O_WRONLY); + if (IS_ERR(anon_file->file)) { + ret = PTR_ERR(anon_file->file); goto err_put_fd; } @@ -299,16 +304,15 @@ static int cachefiles_ondemand_get_fd(struct cachefiles_req *req) if (object->ondemand->ondemand_id > 0) { spin_unlock(&object->ondemand->lock); /* Pair with check in cachefiles_ondemand_fd_release(). */ - file->private_data = NULL; + anon_file->file->private_data = NULL; ret = -EEXIST; goto err_put_file; } - file->f_mode |= FMODE_PWRITE | FMODE_LSEEK; - fd_install(fd, file); + anon_file->file->f_mode |= FMODE_PWRITE | FMODE_LSEEK; load = (void *)req->msg.data; - load->fd = fd; + load->fd = anon_file->fd; object->ondemand->ondemand_id = object_id; spin_unlock(&object->ondemand->lock); @@ -317,9 +321,11 @@ static int cachefiles_ondemand_get_fd(struct cachefiles_req *req) return 0; err_put_file: - fput(file); + fput(anon_file->file); + anon_file->file = NULL; err_put_fd: - put_unused_fd(fd); + put_unused_fd(anon_file->fd); + anon_file->fd = ret; err_free_id: xa_erase(&cache->ondemand_ids, object_id); err: @@ -376,6 +382,7 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, struct cachefiles_msg *msg; size_t n; int ret = 0; + struct ondemand_anon_file anon_file; XA_STATE(xas, &cache->reqs, cache->req_id_next); xa_lock(&cache->reqs); @@ -409,7 +416,7 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, xa_unlock(&cache->reqs); if (msg->opcode == CACHEFILES_OP_OPEN) { - ret = cachefiles_ondemand_get_fd(req); + ret = cachefiles_ondemand_get_fd(req, &anon_file); if (ret) goto out; } @@ -417,10 +424,16 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, msg->msg_id = xas.xa_index; msg->object_id = req->object->ondemand->ondemand_id; - if (copy_to_user(_buffer, msg, n) != 0) { + if (copy_to_user(_buffer, msg, n) != 0) ret = -EFAULT; - if (msg->opcode == CACHEFILES_OP_OPEN) - close_fd(((struct cachefiles_open *)msg->data)->fd); + + if (msg->opcode == CACHEFILES_OP_OPEN) { + if (ret < 0) { + fput(anon_file.file); + put_unused_fd(anon_file.fd); + goto out; + } + fd_install(anon_file.fd, anon_file.file); } out: cachefiles_put_object(req->object, cachefiles_obj_put_read_req); -- 2.39.2
mainline inclusion from mainline-v6.10-rc4 commit 4f8703fb3482f92edcfd31661857b16fec89c2c0 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- If copen is maliciously called in the user mode, it may delete the request corresponding to the random id. And the request may have not been read yet. Note that when the object is set to reopen, the open request will be done with the still reopen state in above case. As a result, the request corresponding to this object is always skipped in select_req function, so the read request is never completed and blocks other process. Fix this issue by simply set object to close if its id < 0 in copen. Signed-off-by: Zizhi Wo <wozizhi@huawei.com> Signed-off-by: Baokun Li <libaokun1@huawei.com> Link: https://lore.kernel.org/r/20240522114308.2402121-11-libaokun@huaweicloud.com Acked-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com> Signed-off-by: Christian Brauner <brauner@kernel.org> --- fs/cachefiles/ondemand.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index b8e9cdc93643..0862d69d6475 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -182,6 +182,7 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) xas_store(&xas, NULL); xa_unlock(&cache->reqs); + info = req->object->ondemand; /* fail OPEN request if copen format is invalid */ ret = kstrtol(psize, 0, &size); if (ret) { @@ -201,7 +202,6 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) goto out; } - info = req->object->ondemand; spin_lock(&info->lock); /* * The anonymous fd was closed before copen ? Fail the request. @@ -241,6 +241,11 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) wake_up_all(&cache->daemon_pollwq); out: + spin_lock(&info->lock); + /* Need to set object close to avoid reopen status continuing */ + if (info->ondemand_id == CACHEFILES_ONDEMAND_ID_CLOSED) + cachefiles_ondemand_set_object_close(req->object); + spin_unlock(&info->lock); complete(&req->done); return ret; } -- 2.39.2
From: Baokun Li <libaokun1@huawei.com> mainline inclusion from mainline-v6.10-rc4 commit 85e833cd7243bda7285492b0653c3abb1e2e757b category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- In ondemand mode, when the daemon is processing an open request, if the kernel flags the cache as CACHEFILES_DEAD, the cachefiles_daemon_write() will always return -EIO, so the daemon can't pass the copen to the kernel. Then the kernel process that is waiting for the copen triggers a hung_task. Since the DEAD state is irreversible, it can only be exited by closing /dev/cachefiles. Therefore, after calling cachefiles_io_error() to mark the cache as CACHEFILES_DEAD, if in ondemand mode, flush all requests to avoid the above hungtask. We may still be able to read some of the cached data before closing the fd of /dev/cachefiles. Note that this relies on the patch that adds reference counting to the req, otherwise it may UAF. Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie") Signed-off-by: Baokun Li <libaokun1@huawei.com> Link: https://lore.kernel.org/r/20240522114308.2402121-12-libaokun@huaweicloud.com Acked-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/daemon.c | 2 +- fs/cachefiles/internal.h | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c index ccb7b707ea4b..06cdf1a8a16f 100644 --- a/fs/cachefiles/daemon.c +++ b/fs/cachefiles/daemon.c @@ -133,7 +133,7 @@ static int cachefiles_daemon_open(struct inode *inode, struct file *file) return 0; } -static void cachefiles_flush_reqs(struct cachefiles_cache *cache) +void cachefiles_flush_reqs(struct cachefiles_cache *cache) { struct xarray *xa = &cache->reqs; struct cachefiles_req *req; diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index 67b4e729b40b..e0eac16e4741 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -188,6 +188,7 @@ extern int cachefiles_has_space(struct cachefiles_cache *cache, * daemon.c */ extern const struct file_operations cachefiles_daemon_fops; +extern void cachefiles_flush_reqs(struct cachefiles_cache *cache); extern void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache); extern void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache); @@ -426,6 +427,8 @@ do { \ pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__); \ fscache_io_error((___cache)->cache); \ set_bit(CACHEFILES_DEAD, &(___cache)->flags); \ + if (cachefiles_in_ondemand_mode(___cache)) \ + cachefiles_flush_reqs(___cache); \ } while (0) #define cachefiles_io_error_obj(object, FMT, ...) \ -- 2.39.2
From: Baokun Li <libaokun1@huawei.com> mainline inclusion from mainline-v6.10-rc4 commit bc9dde6155464e906e630a0a5c17a4cab241ffbb category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Replacing wait_for_completion() with wait_for_completion_killable() in cachefiles_ondemand_send_req() allows us to kill processes that might trigger a hunk_task if the daemon is abnormal. But now only CACHEFILES_OP_READ is killable, because OP_CLOSE and OP_OPEN is initiated from kworker context and the signal is prohibited in these kworker. Note that when the req in xas changes, i.e. xas_load(&xas) != req, it means that a process will complete the current request soon, so wait again for the request to be completed. In addition, add the cachefiles_ondemand_finish_req() helper function to simplify the code. Suggested-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Baokun Li <libaokun1@huawei.com> Link: https://lore.kernel.org/r/20240522114308.2402121-13-libaokun@huaweicloud.com Acked-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/cachefiles/ondemand.c | 40 ++++++++++++++++++++++++++++------------ 1 file changed, 28 insertions(+), 12 deletions(-) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index 0862d69d6475..9513efaeb7ab 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -380,6 +380,20 @@ static struct cachefiles_req *cachefiles_ondemand_select_req(struct xa_state *xa return NULL; } +static inline bool cachefiles_ondemand_finish_req(struct cachefiles_req *req, + struct xa_state *xas, int err) +{ + if (unlikely(!xas || !req)) + return false; + + if (xa_cmpxchg(xas->xa, xas->xa_index, req, NULL, 0) != req) + return false; + + req->error = err; + complete(&req->done); + return true; +} + ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, char __user *_buffer, size_t buflen) { @@ -443,16 +457,8 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, out: cachefiles_put_object(req->object, cachefiles_obj_put_read_req); /* Remove error request and CLOSE request has no reply */ - if (ret || msg->opcode == CACHEFILES_OP_CLOSE) { - xas_reset(&xas); - xas_lock(&xas); - if (xas_load(&xas) == req) { - req->error = ret; - complete(&req->done); - xas_store(&xas, NULL); - } - xas_unlock(&xas); - } + if (ret || msg->opcode == CACHEFILES_OP_CLOSE) + cachefiles_ondemand_finish_req(req, &xas, ret); cachefiles_req_put(req); return ret ? ret : n; } @@ -544,8 +550,18 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object, goto out; wake_up_all(&cache->daemon_pollwq); - wait_for_completion(&req->done); - ret = req->error; +wait: + ret = wait_for_completion_killable(&req->done); + if (!ret) { + ret = req->error; + } else { + ret = -EINTR; + if (!cachefiles_ondemand_finish_req(req, &xas, ret)) { + /* Someone will complete it soon. */ + cpu_relax(); + goto wait; + } + } cachefiles_req_put(req); return ret; out: -- 2.39.2
反馈： 您发送到kernel@openeuler.org的补丁/补丁集，已成功转换为PR！ PR链接地址： https://gitee.com/openeuler/kernel/pulls/9240 邮件列表地址：https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/E... FeedBack: The patch(es) which you have sent to kernel@openeuler.org mailing list has been converted to a pull request successfully! Pull request link: https://gitee.com/openeuler/kernel/pulls/9240 Mailing list address: https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/E...
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