Messages in this thread Patch in this message | | | Date | Sat, 26 Sep 2009 20:54:32 +0200 | From | Arjan van de Ven <> | Subject | [PATCH 9/9] Add explicit bound checks in net/socket.c |
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From: Arjan van de Ven <arjan@linux.intel.com> Subject: [PATCH 9/9] Add explicit bound checks in net/socket.c CC: netdev@vger.kernel.org
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 <arjan@linux.intel.com>
diff --git a/net/socket.c b/net/socket.c index 49917a1..13a8d67 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 > 6) + 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);
-- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org
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