[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 <[email protected]> Signed-off-by: Al Viro <[email protected]>
jadonk · May 11, 2007 · e54dc24 · e54dc24
1 parent 7f13da4
commit e54dc24
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Showing 11 changed files with 206 additions and 29 deletions.
diff --git a/arch/ia64/kernel/audit.c b/arch/ia64/kernel/audit.c
@@ -28,6 +28,15 @@ static unsigned signal_class[] = {
 ~0U
 };
 
+int audit_classify_arch(int arch)
+{
+#ifdef CONFIG_IA32_SUPPORT
+	if (arch == AUDIT_ARCH_I386)
+		return 1;
+#endif
+	return 0;
+}
+
 int audit_classify_syscall(int abi, unsigned syscall)
 {
 #ifdef CONFIG_IA32_SUPPORT

diff --git a/arch/powerpc/kernel/audit.c b/arch/powerpc/kernel/audit.c
@@ -28,6 +28,15 @@ static unsigned signal_class[] = {
 ~0U
 };
 
+int audit_classify_arch(int arch)
+{
+#ifdef CONFIG_PPC64
+	if (arch == AUDIT_ARCH_PPC)
+		return 1;
+#endif
+	return 0;
+}
+
 int audit_classify_syscall(int abi, unsigned syscall)
 {
 #ifdef CONFIG_PPC64

diff --git a/arch/s390/kernel/audit.c b/arch/s390/kernel/audit.c
@@ -28,6 +28,15 @@ static unsigned signal_class[] = {
 ~0U
 };
 
+int audit_classify_arch(int arch)
+{
+#ifdef CONFIG_COMPAT
+	if (arch == AUDIT_ARCH_S390)
+		return 1;
+#endif
+	return 0;
+}
+
 int audit_classify_syscall(int abi, unsigned syscall)
 {
 #ifdef CONFIG_COMPAT

diff --git a/arch/sparc64/kernel/audit.c b/arch/sparc64/kernel/audit.c
@@ -28,6 +28,15 @@ static unsigned signal_class[] = {
 ~0U
 };
 
+int audit_classify_arch(int arch)
+{
+#ifdef CONFIG_SPARC32_COMPAT
+	if (arch == AUDIT_ARCH_SPARC)
+		return 1;
+#endif
+	return 0;
+}
+
 int audit_classify_syscall(int abi, unsigned syscall)
 {
 #ifdef CONFIG_SPARC32_COMPAT

diff --git a/arch/x86_64/kernel/audit.c b/arch/x86_64/kernel/audit.c
@@ -28,6 +28,15 @@ static unsigned signal_class[] = {
 ~0U
 };
 
+int audit_classify_arch(int arch)
+{
+#ifdef CONFIG_IA32_EMULATION
+	if (arch == AUDIT_ARCH_I386)
+		return 1;
+#endif
+	return 0;
+}
+
 int audit_classify_syscall(int abi, unsigned syscall)
 {
 #ifdef CONFIG_IA32_EMULATION

diff --git a/include/linux/audit.h b/include/linux/audit.h
@@ -340,6 +340,7 @@ struct mqstat;
 #define AUDITSC_RESULT(x) ( ((long)(x))<0?AUDITSC_FAILURE:AUDITSC_SUCCESS )
 extern int __init audit_register_class(int class, unsigned *list);
 extern int audit_classify_syscall(int abi, unsigned syscall);
+extern int audit_classify_arch(int arch);
 #ifdef CONFIG_AUDITSYSCALL
 /* These are defined in auditsc.c */
 				/* Public API */
@@ -458,6 +459,7 @@ static inline int audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
 	return 0;
 }
 extern int audit_n_rules;
+extern int audit_signals;
 #else
 #define audit_alloc(t) ({ 0; })
 #define audit_free(t) do { ; } while (0)
@@ -490,6 +492,7 @@ extern int audit_n_rules;
 #define audit_mq_getsetattr(d,s) ({ 0; })
 #define audit_ptrace(t) ((void)0)
 #define audit_n_rules 0
+#define audit_signals 0
 #endif
 
 #ifdef CONFIG_AUDIT

diff --git a/kernel/audit.h b/kernel/audit.h
@@ -83,6 +83,7 @@ struct audit_krule {
 	u32			field_count;
 	char			*filterkey; /* ties events to rules */
 	struct audit_field	*fields;
+	struct audit_field	*arch_f; /* quick access to arch field */
 	struct audit_field	*inode_f; /* quick access to an inode field */
 	struct audit_watch	*watch;	/* associated watch */
 	struct list_head	rlist;	/* entry in audit_watch.rules list */
@@ -131,17 +132,19 @@ extern void audit_handle_ievent(struct inotify_watch *, u32, u32, u32,
 extern int selinux_audit_rule_update(void);
 
 #ifdef CONFIG_AUDITSYSCALL
-extern void __audit_signal_info(int sig, struct task_struct *t);
-static inline void audit_signal_info(int sig, struct task_struct *t)
+extern int __audit_signal_info(int sig, struct task_struct *t);
+static inline int audit_signal_info(int sig, struct task_struct *t)
 {
-	if (unlikely(audit_pid && t->tgid == audit_pid))
-		__audit_signal_info(sig, t);
+	if (unlikely((audit_pid && t->tgid == audit_pid) ||
+		     (audit_signals && !audit_dummy_context())))
+		return __audit_signal_info(sig, t);
+	return 0;
 }
 extern enum audit_state audit_filter_inodes(struct task_struct *,
 					    struct audit_context *);
 extern void audit_set_auditable(struct audit_context *);
 #else
-#define audit_signal_info(s,t)
+#define audit_signal_info(s,t) AUDIT_DISABLED
 #define audit_filter_inodes(t,c) AUDIT_DISABLED
 #define audit_set_auditable(c)
 #endif
diff --git 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);