net: preserve socketpair output on setup failure

socketpair() writes the reserved descriptor numbers to userspace before
creating the sockets and their file objects. A later failure therefore
leaves a modified caller's array despite returning an error, contrary to
POSIX. For example, socketpair(AF_UNIX, SOCK_STREAM, -1, fd) returns
EPROTONOSUPPORT but replaces the array's sentinel values with unused fd
numbers.

Defer the output stores until both file objects have been created, before
installing either descriptor. If a store faults, drop both file references
before releasing the reserved descriptor slots. Keep the early descriptor
reservation and the existing setup-failure cleanup paths.

In practice, I doubt anyone notices. But this aligns with the expected
behavior

Signed-off-by: Steve Grubb <sgrubb@redhat.com>
Link: https://patch.msgid.link/JyK226D0S5CWGUpAC4MO4A@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions