From: Abel Vesa abel.vesa@linaro.org

stable inclusion from stable-v5.10.165 commit 193cd853145b63e670bd73740250983af1475330 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IALILQ CVE: CVE-2022-48873

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

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commit 5bb96c8f9268e2fdb0e5321cbc358ee5941efc15 upstream.

Do not remove the map from the list on error path in fastrpc_init_create_process, instead call fastrpc_map_put, to avoid use-after-free. Do not remove it on fastrpc_device_release either, call fastrpc_map_put instead.

The fastrpc_free_map is the only proper place to remove the map. This is called only after the reference count is 0.

Fixes: b49f6d83e290 ("misc: fastrpc: Fix a possible double free") Cc: stable stable@kernel.org Co-developed-by: Ola Jeppsson ola@snap.com Signed-off-by: Ola Jeppsson ola@snap.com Signed-off-by: Abel Vesa abel.vesa@linaro.org Signed-off-by: Srinivas Kandagatla srinivas.kandagatla@linaro.org Link: https://lore.kernel.org/r/20221124174941.418450-3-srinivas.kandagatla@linaro... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Tengda Wu wutengda2@huawei.com --- drivers/misc/fastrpc.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index 2c3142b4b5dd..e9d6bb2279fb 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -247,6 +247,13 @@ static void fastrpc_free_map(struct kref *ref) dma_buf_put(map->buf); }

+ if (map->fl) { + spin_lock(&map->fl->lock); + list_del(&map->node); + spin_unlock(&map->fl->lock); + map->fl = NULL; + } + kfree(map); }

@@ -1112,12 +1119,7 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl, fl->init_mem = NULL; fastrpc_buf_free(imem); err_alloc: - if (map) { - spin_lock(&fl->lock); - list_del(&map->node); - spin_unlock(&fl->lock); - fastrpc_map_put(map); - } + fastrpc_map_put(map); err: kfree(args);

@@ -1194,10 +1196,8 @@ static int fastrpc_device_release(struct inode *inode, struct file *file) fastrpc_context_put(ctx); }

- list_for_each_entry_safe(map, m, &fl->maps, node) { - list_del(&map->node); + list_for_each_entry_safe(map, m, &fl->maps, node) fastrpc_map_put(map); - }

list_for_each_entry_safe(buf, b, &fl->mmaps, node) { list_del(&buf->node);