diff options
| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2023-09-01 16:46:04 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-09-04 11:00:17 +0100 |
| commit | 718e6b51298e0f254baca0d40ab52a00e004e014 (patch) | |
| tree | a1dbc411e29d32fcbeaad32fa41cd000181fb16c | |
| parent | 5245008738029135af52a2048d9fe9c4dd9be698 (diff) | |
af_unix: Fix msg_controllen test in scm_pidfd_recv() for MSG_CMSG_COMPAT.
Heiko Carstens reported that SCM_PIDFD does not work with MSG_CMSG_COMPAT
because scm_pidfd_recv() always checks msg_controllen against sizeof(struct
cmsghdr).
We need to use sizeof(struct compat_cmsghdr) for the compat case.
Fixes: 5e2ff6704a27 ("scm: add SO_PASSPIDFD and SCM_PIDFD")
Reported-by: Heiko Carstens <hca@linux.ibm.com>
Closes: https://lore.kernel.org/netdev/20230901200517.8742-A-hca@linux.ibm.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Tested-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/net/scm.h | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/include/net/scm.h b/include/net/scm.h index c5bcdf65f55c..e8c76b4be2fe 100644 --- a/include/net/scm.h +++ b/include/net/scm.h @@ -9,6 +9,7 @@ #include <linux/pid.h> #include <linux/nsproxy.h> #include <linux/sched/signal.h> +#include <net/compat.h> /* Well, we should have at least one descriptor open * to accept passed FDs 8) @@ -123,14 +124,17 @@ static inline bool scm_has_secdata(struct socket *sock) static __inline__ void scm_pidfd_recv(struct msghdr *msg, struct scm_cookie *scm) { struct file *pidfd_file = NULL; - int pidfd; + int len, pidfd; - /* - * put_cmsg() doesn't return an error if CMSG is truncated, + /* put_cmsg() doesn't return an error if CMSG is truncated, * that's why we need to opencode these checks here. */ - if ((msg->msg_controllen <= sizeof(struct cmsghdr)) || - (msg->msg_controllen - sizeof(struct cmsghdr)) < sizeof(int)) { + if (msg->msg_flags & MSG_CMSG_COMPAT) + len = sizeof(struct compat_cmsghdr) + sizeof(int); + else + len = sizeof(struct cmsghdr) + sizeof(int); + + if (msg->msg_controllen < len) { msg->msg_flags |= MSG_CTRUNC; return; } |