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authorJens Axboe <axboe@kernel.dk>2020-01-16 19:00:24 -0700
committerJens Axboe <axboe@kernel.dk>2020-01-16 21:43:24 -0700
commit44d282796f81eb1debc1d7cb53245b4cb3214cb5 (patch)
treed18a8dca177002a38c5ee979467c3ae2555dc637 /fs
parent11ba820bf163e224bf5dd44e545a66a44a5b1d7a (diff)
io_uring: only allow submit from owning task
If the credentials or the mm doesn't match, don't allow the task to submit anything on behalf of this ring. The task that owns the ring can pass the file descriptor to another task, but we don't want to allow that task to submit an SQE that then assumes the ring mm and creds if it needs to go async. Cc: stable@vger.kernel.org Suggested-by: Stefan Metzmacher <metze@samba.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs')
-rw-r--r--fs/io_uring.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 52e5764540e4..187dd94fd6b1 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5159,6 +5159,12 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
} else if (to_submit) {
struct mm_struct *cur_mm;
+ if (current->mm != ctx->sqo_mm ||
+ current_cred() != ctx->creds) {
+ ret = -EPERM;
+ goto out;
+ }
+
to_submit = min(to_submit, ctx->sq_entries);
mutex_lock(&ctx->uring_lock);
/* already have mm, so io_submit_sqes() won't try to grab it */

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