From: Arjan van de Ven Date: Mon, 28 Sep 2009 19:57:44 +0000 (-0700) Subject: net: Add explicit bound checks in net/socket.c X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=47379052b5c87707bc6e20a2a4f6ac156fb8357c;p=linux.git 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 --- diff --git a/net/socket.c b/net/socket.c index 49917a1cac7d9..41e8847508aad 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);