diff options
| author | Zhenghang Xiao <kipreyyy@gmail.com> | 2026-06-15 13:25:56 +0300 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2026-06-15 15:19:45 +0300 |
| commit | 7d87a5a284bb34edb3f4e7e312ef403b3385a7b7 (patch) | |
| tree | b5244f301391e84f43d0ee7e06b6b4d714d79aff | |
| parent | 8bbb2ad1f687633a991839bd3efae04ccfb29e19 (diff) | |
| download | linux-7d87a5a284bb34edb3f4e7e312ef403b3385a7b7.tar.xz | |
fuse-uring: clear ent->fuse_req in commit_fetch error path
fuse_uring_commit_fetch() error path called fuse_request_end(req) without
clearing ent->fuse_req when fuse_ring_ent_set_commit() fails. The
still-pending fuse_uring_send_in_task() task-work later dereferences the
dangling pointer through fuse_uring_prepare_send(), causing a
use-after-free.
End the request with fuse_uring_req_end(), which handles all conditions
already.
Annotation/edition by Bernd: The UAF should be fixed by other means already
and actually has to be avoided that way.
Just checking for ent->fuse_req == NULL in fuse_uring_send_in_task()
would be prone to race conditions, because if malicious userspace
would commit requests that have passed the NULL check, but are
in doing args copy, it would still trigger a use-after-free.
Setting ent->fuse_req = NULL in fuse_uring_commit_fetch() still
makes sense, though.
Reported-by: Shuvam Pandey <shuvampandey1@gmail.com>
Reported-by: Berkant Koc <me@berkoc.com>
Signed-off-by: Zhenghang Xiao <kipreyyy@gmail.com>
Signed-off-by: Bernd Schubert <bernd@bsbernd.com>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| -rw-r--r-- | fs/fuse/dev_uring.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/fs/fuse/dev_uring.c b/fs/fuse/dev_uring.c index ba5edf5d01b3..77c8cec43d9c 100644 --- a/fs/fuse/dev_uring.c +++ b/fs/fuse/dev_uring.c @@ -1003,9 +1003,7 @@ static int fuse_uring_commit_fetch(struct io_uring_cmd *cmd, int issue_flags, pr_info_ratelimited("qid=%d commit_id %llu state %d", queue->qid, commit_id, ent->state); spin_unlock(&queue->lock); - req->out.h.error = err; - clear_bit(FR_SENT, &req->flags); - fuse_request_end(req); + fuse_uring_req_end(ent, req, err); return err; } |