netfilter: ip_tables: fix infoleak to userspace
Structures ipt_replace, compat_ipt_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 and the third bugs were introduced before the git epoch; the
second was introduced in 2722971c
(v2.6.17-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>
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parent
42eab94fff
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@ -1262,6 +1262,7 @@ do_replace(struct net *net, const void __user *user, unsigned int len)
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/* overflow check */
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if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
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return -ENOMEM;
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tmp.name[sizeof(tmp.name)-1] = 0;
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newinfo = xt_alloc_table_info(tmp.size);
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if (!newinfo)
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@ -1807,6 +1808,7 @@ compat_do_replace(struct net *net, void __user *user, unsigned int len)
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return -ENOMEM;
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if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
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return -ENOMEM;
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tmp.name[sizeof(tmp.name)-1] = 0;
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newinfo = xt_alloc_table_info(tmp.size);
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if (!newinfo)
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@ -2036,6 +2038,7 @@ do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
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ret = -EFAULT;
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break;
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}
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rev.name[sizeof(rev.name)-1] = 0;
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if (cmd == IPT_SO_GET_REVISION_TARGET)
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target = 1;
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