io_uring: correct check for O_TMPFILE

Commit 72dbde0f2afbe4af8e8595a89c650ae6b9d9c36f upstream.

O_TMPFILE is actually __O_TMPFILE|O_DIRECTORY. This means that the old
check for whether RESOLVE_CACHED can be used would incorrectly think
that O_DIRECTORY could not be used with RESOLVE_CACHED.

Cc: stable@vger.kernel.org # v5.12+
Fixes: 3a81fd02045c ("io_uring: enable LOOKUP_CACHED path resolution for filename lookups")
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Link: https://lore.kernel.org/r/20230807-resolve_cached-o_tmpfile-v3-1-e49323e1ef6f@cyphar.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/io_uring/openclose.c b/io_uring/openclose.c
index 67178e4..008990e 100644 (file)
--- a/io_uring/openclose.c
+++ b/io_uring/openclose.c
@@ -110,9 +110,11 @@ int io_openat2(struct io_kiocb *req, unsigned int issue_flags)
        if (issue_flags & IO_URING_F_NONBLOCK) {
                /*
                 * Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open,
-                * it'll always -EAGAIN
+                * it'll always -EAGAIN. Note that we test for __O_TMPFILE
+                * because O_TMPFILE includes O_DIRECTORY, which isn't a flag
+                * we need to force async for.
                 */
-               if (open->how.flags & (O_TRUNC | O_CREAT | O_TMPFILE))
+               if (open->how.flags & (O_TRUNC | O_CREAT | __O_TMPFILE))
                        return -EAGAIN;
                op.lookup_flags |= LOOKUP_CACHED;
                op.open_flag |= O_NONBLOCK;