security: let security modules use PTRACE_MODE_* with bitmasks

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. Signed-off-by: Jann Horn <[email protected]> Acked-by: Kees Cook <[email protected]> Acked-by: Casey Schaufler <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: James Morris <[email protected]> Cc: "Serge E. Hallyn" <[email protected]> Cc: Andy Shevchenko <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Al Viro <[email protected]> Cc: "Eric W. Biederman" <[email protected]> Cc: Willy Tarreau <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
zhenyw · Jan 21, 2016 · 3dfb7d8 · 3dfb7d8
1 parent 570ac93
commit 3dfb7d8
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Showing 2 changed files with 5 additions and 7 deletions.
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
@@ -398,12 +398,10 @@ static int smk_copy_relabel(struct list_head *nhead, struct list_head *ohead,
  */
 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;
 }

diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c
@@ -281,7 +281,7 @@ static int yama_ptrace_access_check(struct task_struct *child,
 	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(struct task_struct *child,
 		}
 	}
 
-	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);