From 47379052b5c87707bc6e20a2a4f6ac156fb8357c Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Mon, 28 Sep 2009 12:57:44 -0700 Subject: [PATCH] net: Add explicit bound checks in net/socket.c The sys_socketcall() function has a very clever system for the copy size of its arguments. Unfortunately, gcc cannot deal with this in terms of proving that the copy_from_user() is then always in bounds. This is the last (well 9th of this series, but last in the kernel) such case around. With this patch, we can turn on code to make having the boundary provably right for the whole kernel, and detect introduction of new security accidents of this type early on. Signed-off-by: Arjan van de Ven Signed-off-by: David S. Miller --- net/socket.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/socket.c b/net/socket.c index 49917a1cac7d..41e8847508aa 100644 --- a/net/socket.c +++ b/net/socket.c @@ -2098,12 +2098,17 @@ SYSCALL_DEFINE2(socketcall, int, call, unsigned long __user *, args) unsigned long a[6]; unsigned long a0, a1; int err; + unsigned int len; if (call < 1 || call > SYS_ACCEPT4) return -EINVAL; + len = nargs[call]; + if (len > sizeof(a)) + return -EINVAL; + /* copy_from_user should be SMP safe. */ - if (copy_from_user(a, args, nargs[call])) + if (copy_from_user(a, args, len)) return -EFAULT; audit_socketcall(nargs[call] / sizeof(unsigned long), a);