[PATCH V2] audit: log 32-bit socketcalls

From: Richard Guy Briggs
Date: Fri Jan 13 2017 - 04:52:35 EST


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@xxxxxxxxxx>

--
v2:
Move work to audit_socketcall_compat() and use audit_dummy_context().
---
include/linux/audit.h | 16 ++++++++++++++++
net/compat.c | 15 +++++++++++++--
2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 9d4443f..43d8003 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -387,6 +387,18 @@ 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)
+{
+ if (unlikely(!audit_dummy_context())) {
+ int i;
+ unsigned long a[AUDITSC_ARGS];
+
+ for (i=0; i<nargs; i++)
+ a[i] = (unsigned long)args[i];
+ return __audit_socketcall(nargs, a);
+ }
+ return 0;
+}
static inline int audit_sockaddr(int len, void *addr)
{
if (unlikely(!audit_dummy_context()))
@@ -513,6 +525,10 @@ 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 1cd2ec0..f0404d4 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)
{
+ unsigned int len;
int ret;
- u32 a[6];
+ u32 a[AUDITSC_ARGS];
u32 a0, a1;

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];

--
1.7.1