kernel: audit: beautify code, for extern function, better to check its parameters by itself

  __audit_socketcall is an extern function.
  better to check its parameters by itself.

    also can return error code, when fail (find invalid parameters).
    also use macro instead of real hard code number
    also give related comments for it.

Signed-off-by: Chen Gang <gang.chen@asianux.com>
[eparis: fix the return value when !CONFIG_AUDIT]
Signed-off-by: Eric Paris <eparis@redhat.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/net/socket.c b/net/socket.c
index 2ca51c719ef9..1bbc37b7a312 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2436,7 +2436,7 @@ static const unsigned char nargs[21] = {
 
 SYSCALL_DEFINE2(socketcall, int, call, unsigned long __user *, args)
 {
-        unsigned long a[6];
+        unsigned long a[AUDITSC_ARGS];
         unsigned long a0, a1;
         int err;
         unsigned int len;
@@ -2452,7 +2452,9 @@ SYSCALL_DEFINE2(socketcall, int, call, unsigned long __user *, args)
         if (copy_from_user(a, args, len))
                 return -EFAULT;
 
-        audit_socketcall(nargs[call] / sizeof(unsigned long), a);
+        err = audit_socketcall(nargs[call] / sizeof(unsigned long), a);
+        if (err)
+                return err;
 
         a0 = a[0];
         a1 = a[1];