[AUDIT] Don't allow ptrace to fool auditing, log arch of audited syscalls.

We were calling ptrace_notify() after auditing the syscall and arguments,
but the debugger could have _changed_ them before the syscall was actually
invoked. Reorder the calls to fix that.

While we're touching ever call to audit_syscall_entry(), we also make it
take an extra argument: the architecture of the syscall which was made,
because some architectures allow more than one type of syscall.

Also add an explicit success/failure flag to audit_syscall_exit(), for
the benefit of architectures which return that in a condition register
rather than only returning a single register.

Change type of syscall return value to 'long' not 'int'.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

1 files changed, 16 insertions, 6 deletions

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 00e87ff..77e9259 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -123,7 +123,7 @@ struct audit_context {
 	int		    major;      /* syscall number */
 	unsigned long	    argv[4];    /* syscall arguments */
 	int		    return_valid; /* return code is valid */
-	int		    return_code;/* syscall return code */
+	long		    return_code;/* syscall return code */
 	int		    auditable;  /* 1 if record should be written */
 	int		    name_count;
 	struct audit_names  names[AUDIT_NAMES];
@@ -135,6 +135,7 @@ struct audit_context {
 	uid_t		    uid, euid, suid, fsuid;
 	gid_t		    gid, egid, sgid, fsgid;
 	unsigned long	    personality;
+	int		    arch;
 
 #if AUDIT_DEBUG
 	int		    put_count;
@@ -348,6 +349,10 @@ static int audit_filter_rules(struct task_struct *tsk,
 		case AUDIT_PERS:
 			result = (tsk->personality == value);
 			break;
+		case AUDIT_ARCH:
+			if (ctx) 
+				result = (ctx->arch == value);
+			break;
 
 		case AUDIT_EXIT:
 			if (ctx && ctx->return_valid)
@@ -355,7 +360,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 			break;
 		case AUDIT_SUCCESS:
 			if (ctx && ctx->return_valid)
-				result = (ctx->return_code >= 0);
+				result = (ctx->return_valid == AUDITSC_SUCCESS);
 			break;
 		case AUDIT_DEVMAJOR:
 			if (ctx) {
@@ -648,8 +653,11 @@ static void audit_log_exit(struct audit_context *context)
 	audit_log_format(ab, "syscall=%d", context->major);
 	if (context->personality != PER_LINUX)
 		audit_log_format(ab, " per=%lx", context->personality);
+	audit_log_format(ab, " arch=%x", context->arch);
 	if (context->return_valid)
-		audit_log_format(ab, " exit=%d", context->return_code);
+		audit_log_format(ab, " success=%s exit=%ld", 
+				 (context->return_valid==AUDITSC_SUCCESS)?"yes":"no",
+				 context->return_code);
 	audit_log_format(ab,
 		  " a0=%lx a1=%lx a2=%lx a3=%lx items=%d"
 		  " pid=%d loginuid=%d uid=%d gid=%d"
@@ -773,7 +781,7 @@ static inline unsigned int audit_serial(void)
  * then the record will be written at syscall exit time (otherwise, it
  * will only be written if another part of the kernel requests that it
  * be written). */
-void audit_syscall_entry(struct task_struct *tsk, int major,
+void audit_syscall_entry(struct task_struct *tsk, int arch, int major,
 			 unsigned long a1, unsigned long a2,
 			 unsigned long a3, unsigned long a4)
 {
@@ -827,6 +835,7 @@ void audit_syscall_entry(struct task_struct *tsk, int major,
 	if (!audit_enabled)
 		return;
 
+	context->arch	    = arch;
 	context->major      = major;
 	context->argv[0]    = a1;
 	context->argv[1]    = a2;
@@ -850,13 +859,13 @@ void audit_syscall_entry(struct task_struct *tsk, int major,
  * filtering, or because some other part of the kernel write an audit
  * message), then write out the syscall information.  In call cases,
  * free the names stored from getname(). */
-void audit_syscall_exit(struct task_struct *tsk, int return_code)
+void audit_syscall_exit(struct task_struct *tsk, int valid, long return_code)
 {
 	struct audit_context *context;
 
 	get_task_struct(tsk);
 	task_lock(tsk);
-	context = audit_get_context(tsk, 1, return_code);
+	context = audit_get_context(tsk, valid, return_code);
 	task_unlock(tsk);
 
 	/* Not having a context here is ok, since the parent may have
@@ -869,6 +878,7 @@ void audit_syscall_exit(struct task_struct *tsk, int return_code)
 
 	context->in_syscall = 0;
 	context->auditable  = 0;
+
 	if (context->previous) {
 		struct audit_context *new_context = context->previous;
 		context->previous  = NULL;