The patch titled
Subject: ipc/msg: lockless security checks for msgsnd
has been added to the -mm tree. Its filename is
ipc-msg-lockless-security-checks-for-msgsnd.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/ipc-msg-lockless-security-checks-for-msgsnd.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/ipc-msg-lockless-security-checks-for-msgsnd.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Subject: ipc/msg: lockless security checks for msgsnd
Just as with msgrcv (along with the rest of sysvipc since a few years
ago), perform the security checks without holding the ipc object lock.
This also reduces the hogging of the lock for the entire duration of a
sender, as we drop the lock upon every iteration -- and this is exactly
why we also check for racing with RMID in the first place.
Link: http://lkml.kernel.org/r/1469748819-19484-5-git-send-email-dave@xxxxxxxxxxxx
Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
ipc/msg.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff -puN ipc/msg.c~ipc-msg-lockless-security-checks-for-msgsnd ipc/msg.c
--- a/ipc/msg.c~ipc-msg-lockless-security-checks-for-msgsnd
+++ a/ipc/msg.c
@@ -623,14 +623,14 @@ long do_msgsnd(int msqid, long mtype, vo
goto out_unlock1;
}
- ipc_lock_object(&msq->q_perm);
-
for (;;) {
struct msg_sender s;
err = -EACCES;
if (ipcperms(ns, &msq->q_perm, S_IWUGO))
- goto out_unlock0;
+ goto out_unlock1;
+
+ ipc_lock_object(&msq->q_perm);
/* raced with RMID? */
if (!ipc_valid_object(&msq->q_perm)) {
@@ -681,6 +681,7 @@ long do_msgsnd(int msqid, long mtype, vo
goto out_unlock0;
}
+ ipc_unlock_object(&msq->q_perm);
}
msq->q_lspid = task_tgid_vnr(current);
msq->q_stime = get_seconds();
_
Patches currently in -mm which might be from dave@xxxxxxxxxxxx are
ipc-msg-batch-queue-sender-wakeups.patch
ipc-msg-make-ss_wakeup-kill-arg-boolean.patch
ipc-msg-lockless-security-checks-for-msgsnd.patch
ipc-msg-avoid-waking-sender-upon-full-queue.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
