audit: log 32-bit socketcalls

32-bit socketcalls were not being logged by audit on x86_64 systems.
Log them.  This is basically a duplicate of the call from
net/socket.c:sys_socketcall(), but it addresses the impedance mismatch
between 32-bit userspace process and 64-bit kernel audit.

See: https://github.com/linux-audit/audit-kernel/issues/14

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Moore <paul@paul-moore.com>

2 files changed, 34 insertions, 3 deletions

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 9d4443f93db6..2be99b276d29 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -387,6 +387,20 @@ static inline int audit_socketcall(int nargs, unsigned long *args)
                 return __audit_socketcall(nargs, args);
         return 0;
 }
+
+static inline int audit_socketcall_compat(int nargs, u32 *args)
+{
+        unsigned long a[AUDITSC_ARGS];
+        int i;
+
+        if (audit_dummy_context())
+                return 0;
+
+        for (i = 0; i < nargs; i++)
+                a[i] = (unsigned long)args[i];
+        return __audit_socketcall(nargs, a);
+}
+
 static inline int audit_sockaddr(int len, void *addr)
 {
         if (unlikely(!audit_dummy_context()))
@@ -513,6 +527,12 @@ static inline int audit_socketcall(int nargs, unsigned long *args)
 {
         return 0;
 }
+
+static inline int audit_socketcall_compat(int nargs, u32 *args)
+{
+        return 0;
+}
+
 static inline void audit_fd_pair(int fd1, int fd2)
 { }
 static inline int audit_sockaddr(int len, void *addr)
diff --git a/net/compat.c b/net/compat.c
index 1cd2ec046164..a96fd2f3507b 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -22,6 +22,7 @@
 #include <linux/filter.h>
 #include <linux/compat.h>
 #include <linux/security.h>
+#include <linux/audit.h>
 #include <linux/export.h>
 
 #include <net/scm.h>
@@ -781,14 +782,24 @@ COMPAT_SYSCALL_DEFINE5(recvmmsg, int, fd, struct compat_mmsghdr __user *, mmsg,
 
 COMPAT_SYSCALL_DEFINE2(socketcall, int, call, u32 __user *, args)
 {
-        int ret;
-        u32 a[6];
+        u32 a[AUDITSC_ARGS];
+        unsigned int len;
         u32 a0, a1;
+        int ret;
 
         if (call < SYS_SOCKET || call > SYS_SENDMMSG)
                 return -EINVAL;
-        if (copy_from_user(a, args, nas[call]))
+        len = nas[call];
+        if (len > sizeof(a))
+                return -EINVAL;
+
+        if (copy_from_user(a, args, len))
                 return -EFAULT;
+
+        ret = audit_socketcall_compat(len / sizeof(a[0]), a);
+        if (ret)
+                return ret;
+
         a0 = a[0];
         a1 = a[1];