On 12/24/25 9:42 AM, Prithvi Tambewagh wrote:
__io_openat_prep() allocates a struct filename using getname(), but it isn't freed in case the present file is installed in the fixed file table and simultaneously, it has the flag O_CLOEXEC set in the open->how.flags field.
This is an erroneous condition, since for a file installed in the fixed file table, it won't be installed in the normal file table, due to which the file cannot support close on exec. Earlier, the code just returned -EINVAL error code for this condition, however, the memory allocated for that struct filename wasn't freed, resulting in a memory leak.
Hence, the case of file being installed in the fixed file table as well as having O_CLOEXEC flag in open->how.flags set, is adressed by using putname() to release the memory allocated to the struct filename, then setting the field open->filename to NULL, and after that, returning -EINVAL.
Reported-by: syzbot+00e61c43eb5e4740438f@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=00e61c43eb5e4740438f Tested-by: syzbot+00e61c43eb5e4740438f@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Signed-off-by: Prithvi Tambewagh activprithvi@gmail.com
io_uring/openclose.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/io_uring/openclose.c b/io_uring/openclose.c index bfeb91b31bba..fc190a3d8112 100644 --- a/io_uring/openclose.c +++ b/io_uring/openclose.c @@ -75,8 +75,11 @@ static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe } open->file_slot = READ_ONCE(sqe->file_index);
- if (open->file_slot && (open->how.flags & O_CLOEXEC))
- if (open->file_slot && (open->how.flags & O_CLOEXEC)) {
putname(open->filename);open->filename = NULL;- }
open->nofile = rlimit(RLIMIT_NOFILE); req->flags |= REQ_F_NEED_CLEANUP;
You can probably fix it similarly by just having REQ_F_NEED_CLEANUP set earlier in the process, then everything that needs undoing will get undone as part of ending the request.