Patch "security: let security modules use PTRACE_MODE_* with bitmasks" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

security: let security modules use PTRACE_MODE_* with bitmasks

to the 4.4-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-let-security-modules-use-ptrace_mode_-with-bitmasks.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jann Horn <[email protected]>
Date: Wed, 20 Jan 2016 15:00:01 -0800
Subject: security: let security modules use PTRACE_MODE_* with bitmasks

From: Jann Horn <[email protected]>

commit 3dfb7d8cdbc7ea0c2970450e60818bb3eefbad69 upstream.

It looks like smack and yama weren't aware that the ptrace mode can have flags ORed into it - PTRACE_MODE_NOAUDIT until now, but only for /proc/$pid/stat, and with the PTRACE_MODE_*CREDS patch, all modes have flags ORed into them.

---
 security/smack/smack_lsm.c |    8 +++-----
 security/yama/yama_lsm.c   |    4 ++--
 2 files changed, 5 insertions(+), 7 deletions(-)

@@ -398,12 +398,10 @@ static int smk_copy_relabel(struct list_
  */
 static inline unsigned int smk_ptrace_mode(unsigned int mode)
 {
-	switch (mode) {
-	case PTRACE_MODE_READ:
-		return MAY_READ;
-	case PTRACE_MODE_ATTACH:
+	if (mode & PTRACE_MODE_ATTACH)
 		return MAY_READWRITE;
-	}
+	if (mode & PTRACE_MODE_READ)
+		return MAY_READ;
 
 	return 0;
 }

@@ -281,7 +281,7 @@ static int yama_ptrace_access_check(stru
 	int rc = 0;
 
 	/* require ptrace target be a child of ptracer on attach */
-	if (mode == PTRACE_MODE_ATTACH) {
+	if (mode & PTRACE_MODE_ATTACH) {
 		switch (ptrace_scope) {
 		case YAMA_SCOPE_DISABLED:
 			/* No additional restrictions. */

@@ -307,7 +307,7 @@ static int yama_ptrace_access_check(stru
 		}
 	}
 
-	if (rc) {
+	if (rc && (mode & PTRACE_MODE_NOAUDIT) == 0) {
 		printk_ratelimited(KERN_NOTICE
 			"ptrace of pid %d was attempted by: %s (pid %d)\n",
 			child->pid, current->comm, current->pid);

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/seccomp-always-propagate-no_new_privs-on-tsync.patch queue-4.4/security-let-security-modules-use-ptrace_mode_-with-bitmasks.patch