Messages in this thread Patch in this message |  | | From | Rusty Russell <> | | Subject | Re: [CHECKER] 9 potential copy_*_user bugs in 2.4.1 | | Date | Tue, 20 Mar 2001 19:42:56 +1100 |
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In message <200103160224.SAA03920@csl.Stanford.EDU> you write: > Hi, > > I wrote an extension to gcc that does global analysis to determine > which pointers in 2.4.1 are ever treated as user space pointers (i.e, > passed to copy_*_user, verify_area, etc) and then makes sure they are > always treated that way.
Hi Dawson,
FYI, you missed one, which was fixed in 2.4.2. This is tricky since ip_fw_ctl is defined in TWO (mutually exclusive) places: ipfwadm_core.c and ipchains_core.c.
Oh, I see in a later message that you do CONFIG=y. Hmm, you won't even get asked about these if you've said CONFIG=y to CONFIG_IPTABLES. You're best off trying CONFIG=m, which allows a compile of everything, but that may be outside your framework, in which case a series of different configurations might be in order...
diff -u --recursive --new-file v2.4.1/linux/net/ipv4/netfilter/ip_fw_compat.c linux/net/ipv4/netfilter/ip_fw_compat.c --- v2.4.1/linux/net/ipv4/netfilter/ip_fw_compat.c Mon Sep 18 15:09:55 2000 +++ linux/net/ipv4/netfilter/ip_fw_compat.c Fri Feb 9 11:34:13 2001 @@ -9,6 +9,7 @@ #include <linux/inetdevice.h> #include <linux/netdevice.h> #include <linux/module.h> +#include <asm/uaccess.h> #include <net/ip.h> #include <net/route.h> #include <linux/netfilter_ipv4/compat_firewall.h> @@ -197,14 +198,28 @@ return NF_ACCEPT; } -extern int ip_fw_ctl(int optval, void *user, unsigned int len); +extern int ip_fw_ctl(int optval, void *m, unsigned int len); static int sock_fn(struct sock *sk, int optval, void *user, unsigned int len) { + /* MAX of: + 2.2: sizeof(struct ip_fwtest) (~14x4 + 3x4 = 17x4) + 2.2: sizeof(struct ip_fwnew) (~1x4 + 15x4 + 3x4 + 3x4 = 22x4) + 2.0: sizeof(struct ip_fw) (~25x4) + + We can't include both 2.0 and 2.2 headers, they conflict. + Hence, 200 is a good number. --RR */ + char tmp_fw[200]; if (!capable(CAP_NET_ADMIN)) return -EPERM; - return -ip_fw_ctl(optval, user, len); + if (len > sizeof(tmp_fw) || len < 1) + return -EINVAL; + + if (copy_from_user(&tmp_fw, user, len)) + return -EFAULT; + + return -ip_fw_ctl(optval, &tmp_fw, len); } static struct nf_hook_ops preroute_ops Hope that helps, and keep up the great work! Rusty. -- Premature optmztion is rt of all evl. --DK
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