* Patch "security_syslog() should be called once only" has been added to the 4.1-stable tree
@ 2015-07-31 1:24 gregkh
0 siblings, 0 replies; only message in thread
From: gregkh @ 2015-07-31 1:24 UTC (permalink / raw)
To: vvs, akpm, eparis, gregkh, jwboyer, keescook, torvalds
Cc: stable, stable-commits
This is a note to let you know that I've just added the patch titled
security_syslog() should be called once only
to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
security_syslog-should-be-called-once-only.patch
and it can be found in the queue-4.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From d194e5d666225b04c7754471df0948f645b6ab3a Mon Sep 17 00:00:00 2001
From: Vasily Averin <vvs@virtuozzo.com>
Date: Thu, 25 Jun 2015 15:01:44 -0700
Subject: security_syslog() should be called once only
From: Vasily Averin <vvs@virtuozzo.com>
commit d194e5d666225b04c7754471df0948f645b6ab3a upstream.
The final version of commit 637241a900cb ("kmsg: honor dmesg_restrict
sysctl on /dev/kmsg") lost few hooks, as result security_syslog() are
processed incorrectly:
- open of /dev/kmsg checks syslog access permissions by using
check_syslog_permissions() where security_syslog() is not called if
dmesg_restrict is set.
- syslog syscall and /proc/kmsg calls do_syslog() where security_syslog
can be executed twice (inside check_syslog_permissions() and then
directly in do_syslog())
With this patch security_syslog() is called once only in all
syslog-related operations regardless of dmesg_restrict value.
Fixes: 637241a900cb ("kmsg: honor dmesg_restrict sysctl on /dev/kmsg")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/printk/printk.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -484,11 +484,11 @@ int check_syslog_permissions(int type, b
* already done the capabilities checks at open time.
*/
if (from_file && type != SYSLOG_ACTION_OPEN)
- return 0;
+ goto ok;
if (syslog_action_restricted(type)) {
if (capable(CAP_SYSLOG))
- return 0;
+ goto ok;
/*
* For historical reasons, accept CAP_SYS_ADMIN too, with
* a warning.
@@ -498,10 +498,11 @@ int check_syslog_permissions(int type, b
"CAP_SYS_ADMIN but no CAP_SYSLOG "
"(deprecated).\n",
current->comm, task_pid_nr(current));
- return 0;
+ goto ok;
}
return -EPERM;
}
+ok:
return security_syslog(type);
}
@@ -1263,10 +1264,6 @@ int do_syslog(int type, char __user *buf
if (error)
goto out;
- error = security_syslog(type);
- if (error)
- return error;
-
switch (type) {
case SYSLOG_ACTION_CLOSE: /* Close log */
break;
Patches currently in stable-queue which might be from vvs@virtuozzo.com are
queue-4.1/security_syslog-should-be-called-once-only.patch
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2015-07-31 1:24 Patch "security_syslog() should be called once only" has been added to the 4.1-stable tree gregkh
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