[PATCH] audit signal recipients

When auditing syscalls that send signals, log the pid and security
context for each target process. Optimize the data collection by
adding a counter for signal-related rules, and avoiding allocating an
aux struct unless we have more than one target process. For process
groups, collect pid/context data in blocks of 16. Move the
audit_signal_info() hook up in check_kill_permission() so we audit
attempts where permission is denied.

Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 47 insertions, 1 deletions

diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 3749193aed8c..6c61263ff96d 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -311,6 +311,43 @@ int audit_match_class(int class, unsigned syscall)
         return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
 }
 
+static inline int audit_match_class_bits(int class, u32 *mask)
+{
+        int i;
+
+        if (classes[class]) {
+                for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
+                        if (mask[i] & classes[class][i])
+                                return 0;
+        }
+        return 1;
+}
+
+static int audit_match_signal(struct audit_entry *entry)
+{
+        struct audit_field *arch = entry->rule.arch_f;
+
+        if (!arch) {
+                /* When arch is unspecified, we must check both masks on biarch
+                 * as syscall number alone is ambiguous. */
+                return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
+                                               entry->rule.mask) &&
+                        audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
+                                               entry->rule.mask));
+        }
+
+        switch(audit_classify_arch(arch->val)) {
+        case 0: /* native */
+                return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
+                                               entry->rule.mask));
+        case 1: /* 32bit on biarch */
+                return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
+                                               entry->rule.mask));
+        default:
+                return 1;
+        }
+}
+
 /* Common user-space to kernel rule translation. */
 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
 {
@@ -429,6 +466,7 @@ static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
                                 err = -EINVAL;
                                 goto exit_free;
                         }
+                        entry->rule.arch_f = f;
                         break;
                 case AUDIT_PERM:
                         if (f->val & ~15)
@@ -519,7 +557,6 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
                 case AUDIT_FSGID:
                 case AUDIT_LOGINUID:
                 case AUDIT_PERS:
-                case AUDIT_ARCH:
                 case AUDIT_MSGTYPE:
                 case AUDIT_PPID:
                 case AUDIT_DEVMAJOR:
@@ -531,6 +568,9 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
                 case AUDIT_ARG2:
                 case AUDIT_ARG3:
                         break;
+                case AUDIT_ARCH:
+                        entry->rule.arch_f = f;
+                        break;
                 case AUDIT_SUBJ_USER:
                 case AUDIT_SUBJ_ROLE:
                 case AUDIT_SUBJ_TYPE:
@@ -1221,6 +1261,9 @@ static inline int audit_add_rule(struct audit_entry *entry,
 #ifdef CONFIG_AUDITSYSCALL
         if (!dont_count)
                 audit_n_rules++;
+
+        if (!audit_match_signal(entry))
+                audit_signals++;
 #endif
         mutex_unlock(&audit_filter_mutex);
 
@@ -1294,6 +1337,9 @@ static inline int audit_del_rule(struct audit_entry *entry,
 #ifdef CONFIG_AUDITSYSCALL
         if (!dont_count)
                 audit_n_rules--;
+
+        if (!audit_match_signal(entry))
+                audit_signals--;
 #endif
         mutex_unlock(&audit_filter_mutex);