syslog: distinguish between /proc/kmsg and syscalls

This allows the LSM to distinguish between syslog functions originating
from /proc/kmsg access and direct syscalls.  By default, the commoncaps
will now no longer require CAP_SYS_ADMIN to read an opened /proc/kmsg
file descriptor.  For example the kernel syslog reader can now drop
privileges after opening /proc/kmsg, instead of staying privileged with
CAP_SYS_ADMIN.  MAC systems that implement security_syslog have unchanged
behavior.

Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/security/security.c b/security/security.c
index 440afe5eb54c..971092c06f31 100644
--- a/security/security.c
+++ b/security/security.c
@@ -203,9 +203,9 @@ int security_quota_on(struct dentry *dentry)
         return security_ops->quota_on(dentry);
 }
 
-int security_syslog(int type)
+int security_syslog(int type, bool from_file)
 {
-        return security_ops->syslog(type);
+        return security_ops->syslog(type, from_file);
 }
 
 int security_settime(struct timespec *ts, struct timezone *tz)