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io_uring: fix filename leak in __io_openat_prep()

PATCH Applied Prithvi Tambewagh 2 participants 4 messages Dec 25, 2025

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Prithvi Tambewagh

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#0 lore raw

PATCH v2 1/1 io_uring: fix filename leak in __io_openat_prep()

__io_openat_prep() allocates a struct filename using getname(). However,
for the condition of the file being installed in the fixed file table as well as having O_CLOEXEC flag set, the function returns early. At that point, the request doesn't have REQ_F_NEED_CLEANUP flag set. Due to this, the memory for the newly allocated struct filename is not cleaned up, causing a memory leak.

Fix this by setting the REQ_F_NEED_CLEANUP for the request just after the successful getname() call, so that when the request is torn down, the filename will be cleaned up, along with other resources needing cleanup.

Reported-by [email protected]
Closes https://syzkaller.appspot.com/bug?extid=00e61c43eb5e4740438f
Tested-by [email protected]
Cc [email protected]
Signed-off-by Prithvi Tambewagh <[email protected]>
---
 io_uring/openclose.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
io_uring/openclose.c +1 -1
index bfeb91b31bba..15dde9bd6ff6 100644
@@ -73,13 +73,13 @@ static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe
 		open->filename = NULL;
 		return ret;
 	}
+	req->flags |= REQ_F_NEED_CLEANUP;
 
 	open->file_slot = READ_ONCE(sqe->file_index);
 	if (open->file_slot && (open->how.flags & O_CLOEXEC))
 		return -EINVAL;
 
 	open->nofile = rlimit(RLIMIT_NOFILE);
-	req->flags |= REQ_F_NEED_CLEANUP;
 	if (io_openat_force_async(open))
 		req->flags |= REQ_F_FORCE_ASYNC;
 	return 0;

base-commit: b927546677c876e26eba308550207c2ddf812a43

Signature · 1 line
2.34.1
maintainer
#1 lore raw
Quoted 11 lines · Prithvi Tambewagh

__io_openat_prep() allocates a struct filename using getname(). However,
for the condition of the file being installed in the fixed file table as well as having O_CLOEXEC flag set, the function returns early. At that point, the request doesn't have REQ_F_NEED_CLEANUP flag set. Due to this, the memory for the newly allocated struct filename is not cleaned up, causing a memory leak.

Fix this by setting the REQ_F_NEED_CLEANUP for the request just after the successful getname() call, so that when the request is torn down, the filename will be cleaned up, along with other resources needing cleanup.

Quoted 5 lines
Reported-by [email protected]
Closes https://syzkaller.appspot.com/bug?extid=00e61c43eb5e4740438f
Tested-by [email protected]
Cc [email protected]
Signed-off-by Prithvi Tambewagh <[email protected]>

Thanks, just missing a:

Fixes b9445598d8c6 ("io_uring: openat directly into fixed fd table")

which I'll add when applying.

Signature · 1 line
Jens Axboe
maintainer Applied
#2 lore raw
In reply to Prithvi Tambewagh
Quoted 8 lines · Prithvi Tambewagh

__io_openat_prep() allocates a struct filename using getname(). However,
for the condition of the file being installed in the fixed file table as well as having O_CLOEXEC flag set, the function returns early. At that point, the request doesn't have REQ_F_NEED_CLEANUP flag set. Due to this, the memory for the newly allocated struct filename is not cleaned up, causing a memory leak.

[...]

Applied, thanks!

[1/1] io_uring: fix filename leak in __io_openat_prep()

      commit: b14fad555302a2104948feaff70503b64c80ac01

Best regards,

Signature · 1 line
Jens Axboe
author
#3 lore raw
Quoted 9 lines · Jens Axboe
Quoted 7 lines · Prithvi Tambewagh

__io_openat_prep() allocates a struct filename using getname(). However,
for the condition of the file being installed in the fixed file table as well as having O_CLOEXEC flag set, the function returns early. At that point, the request doesn't have REQ_F_NEED_CLEANUP flag set. Due to this, the memory for the newly allocated struct filename is not cleaned up, causing a memory leak.

Quoted 13 lines
Quoted 1 line

[...]

Applied, thanks!

[1/1] io_uring: fix filename leak in __io_openat_prep()

      commit: b14fad555302a2104948feaff70503b64c80ac01

Best regards,

Signature · 1 line
Jens Axboe

Thank you!

Best Regards,
Prithvi