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ipv6: netfilter: ip6_tables: fix infoleak to userspace

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Structures ip6t_replace, compat_ip6t_replace, and xt_get_revision are
copied from userspace.  Fields of these structs that are
zero-terminated strings are not checked.  When they are used as argument
to a format string containing "%s" in request_module(), some sensitive
information is leaked to userspace via argument of spawned modprobe
process.

The first bug was introduced before the git epoch;  the second was
introduced in 3bc3fe5e (v2.6.25-rc1);  the third is introduced by
6b7d31fc (v2.6.15-rc1).  To trigger the bug one should have
CAP_NET_ADMIN.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Vasiliy Kulikov 2011-03-15 13:37:13 +01:00 committed by Patrick McHardy
parent 78b7987676
commit 6a8ab06077
1 changed files with 3 additions and 0 deletions
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3
net/ipv6/netfilter/ip6_tables.c
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@ -1275,6 +1275,7 @@ do_replace(struct net *net, const void __user *user, unsigned int len)
/* overflow check */ /* overflow check */
if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
return -ENOMEM; return -ENOMEM;
tmp.name[sizeof(tmp.name)-1] = 0;
newinfo = xt_alloc_table_info(tmp.size); newinfo = xt_alloc_table_info(tmp.size);
if (!newinfo) if (!newinfo)
@ -1822,6 +1823,7 @@ compat_do_replace(struct net *net, void __user *user, unsigned int len)
return -ENOMEM; return -ENOMEM;
if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
return -ENOMEM; return -ENOMEM;
tmp.name[sizeof(tmp.name)-1] = 0;
newinfo = xt_alloc_table_info(tmp.size); newinfo = xt_alloc_table_info(tmp.size);
if (!newinfo) if (!newinfo)
@ -2051,6 +2053,7 @@ do_ip6t_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
ret = -EFAULT; ret = -EFAULT;
break; break;
} }
rev.name[sizeof(rev.name)-1] = 0;
if (cmd == IP6T_SO_GET_REVISION_TARGET) if (cmd == IP6T_SO_GET_REVISION_TARGET)
target = 1; target = 1;