From: Namjae Jeon linkinjeon@kernel.org

stable inclusion from stable-v5.15.157 commit 88b7f1143b15b29cccb8392b4f38e75b7bb3e300 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9EYBG CVE: CVE-2024-26811

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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[ Upstream commit a677ebd8ca2f2632ccdecbad7b87641274e15aac ]

If installing malicious ksmbd-tools, ksmbd.mountd can return invalid ipc response to ksmbd kernel server. ksmbd should validate payload size of ipc response from ksmbd.mountd to avoid memory overrun or slab-out-of-bounds. This patch validate 3 ipc response that has payload.

Cc: stable@vger.kernel.org Reported-by: Chao Ma machao2019@gmail.com Signed-off-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org Conflicts: fs/ksmbd/ksmbd_netlink.h Signed-off-by: ZhaoLong Wang wangzhaolong1@huawei.com --- fs/ksmbd/ksmbd_netlink.h | 3 ++- fs/ksmbd/mgmt/share_config.c | 7 ++++++- fs/ksmbd/transport_ipc.c | 37 ++++++++++++++++++++++++++++++++++++ 3 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/fs/ksmbd/ksmbd_netlink.h b/fs/ksmbd/ksmbd_netlink.h index 583f95be5284..2fcee69a4e1e 100644 --- a/fs/ksmbd/ksmbd_netlink.h +++ b/fs/ksmbd/ksmbd_netlink.h @@ -162,7 +162,8 @@ struct ksmbd_share_config_response { __u16 force_directory_mode; __u16 force_uid; __u16 force_gid; - __u32 reserved[128]; /* Reserved room */ + __u32 reserved[127]; /* Reserved room */ + __u32 payload_sz; __u32 veto_list_sz; __s8 ____payload[]; }; diff --git a/fs/ksmbd/mgmt/share_config.c b/fs/ksmbd/mgmt/share_config.c index 70655af93b44..8550fc5a3a78 100644 --- a/fs/ksmbd/mgmt/share_config.c +++ b/fs/ksmbd/mgmt/share_config.c @@ -139,7 +139,12 @@ static struct ksmbd_share_config *share_config_request(char *name) share->name = kstrdup(name, GFP_KERNEL);

if (!test_share_config_flag(share, KSMBD_SHARE_FLAG_PIPE)) { - share->path = kstrdup(ksmbd_share_config_path(resp), + int path_len = PATH_MAX; + + if (resp->payload_sz) + path_len = resp->payload_sz - resp->veto_list_sz; + + share->path = kstrndup(ksmbd_share_config_path(resp), path_len, GFP_KERNEL); if (share->path) share->path_sz = strlen(share->path); diff --git a/fs/ksmbd/transport_ipc.c b/fs/ksmbd/transport_ipc.c index cf88f0aa48e0..e42e785d253c 100644 --- a/fs/ksmbd/transport_ipc.c +++ b/fs/ksmbd/transport_ipc.c @@ -64,6 +64,7 @@ struct ipc_msg_table_entry { struct hlist_node ipc_table_hlist;

void *response; + unsigned int msg_sz; };

static struct delayed_work ipc_timer_work; @@ -273,6 +274,7 @@ static int handle_response(int type, void *payload, size_t sz) }

memcpy(entry->response, payload, sz); + entry->msg_sz = sz; wake_up_interruptible(&entry->wait); ret = 0; break; @@ -446,6 +448,34 @@ static int ipc_msg_send(struct ksmbd_ipc_msg *msg) return ret; }

+static int ipc_validate_msg(struct ipc_msg_table_entry *entry) +{ + unsigned int msg_sz = entry->msg_sz; + + if (entry->type == KSMBD_EVENT_RPC_REQUEST) { + struct ksmbd_rpc_command *resp = entry->response; + + msg_sz = sizeof(struct ksmbd_rpc_command) + resp->payload_sz; + } else if (entry->type == KSMBD_EVENT_SPNEGO_AUTHEN_REQUEST) { + struct ksmbd_spnego_authen_response *resp = entry->response; + + msg_sz = sizeof(struct ksmbd_spnego_authen_response) + + resp->session_key_len + resp->spnego_blob_len; + } else if (entry->type == KSMBD_EVENT_SHARE_CONFIG_REQUEST) { + struct ksmbd_share_config_response *resp = entry->response; + + if (resp->payload_sz) { + if (resp->payload_sz < resp->veto_list_sz) + return -EINVAL; + + msg_sz = sizeof(struct ksmbd_share_config_response) + + resp->payload_sz; + } + } + + return entry->msg_sz != msg_sz ? -EINVAL : 0; +} + static void *ipc_msg_send_request(struct ksmbd_ipc_msg *msg, unsigned int handle) { struct ipc_msg_table_entry entry; @@ -470,6 +500,13 @@ static void *ipc_msg_send_request(struct ksmbd_ipc_msg *msg, unsigned int handle ret = wait_event_interruptible_timeout(entry.wait, entry.response != NULL, IPC_WAIT_TIMEOUT); + if (entry.response) { + ret = ipc_validate_msg(&entry); + if (ret) { + kvfree(entry.response); + entry.response = NULL; + } + } out: down_write(&ipc_msg_table_lock); hash_del(&entry.ipc_table_hlist);