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>
This commit is contained in:
Kees Cook
2010-02-03 15:36:43 -08:00
committed by James Morris
parent 0719aaf5ea
commit 002345925e
8 changed files with 59 additions and 22 deletions

View File

@@ -157,12 +157,12 @@ static int smack_ptrace_traceme(struct task_struct *ptp)
*
* Returns 0 on success, error code otherwise.
*/
static int smack_syslog(int type)
static int smack_syslog(int type, bool from_file)
{
int rc;
char *sp = current_security();
rc = cap_syslog(type);
rc = cap_syslog(type, from_file);
if (rc != 0)
return rc;