From patchwork Mon Jul 4 09:53:39 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [5/6] netfilter: arp_tables: fix infoleak to userspace CVE-2011-1170 Date: Sun, 03 Jul 2011 23:53:39 -0000 From: Paolo Pisati X-Patchwork-Id: 103063 Message-Id: <1309773220-2418-6-git-send-email-paolo.pisati@canonical.com> To: kernel-team@lists.ubuntu.com From: Vasiliy Kulikov BugLink: http://bugs.launchpad.net/bugs/801480 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 bug was introduced before the git epoch; the second is introduced by 6b7d31fc (v2.6.15-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 Signed-off-by: Patrick McHardy Signed-off-by: Paolo Pisati --- net/ipv4/netfilter/arp_tables.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index 2909c92..da85e92 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -816,6 +816,7 @@ static int do_replace(void __user *user, unsigned int len) return -ENOMEM; if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) return -ENOMEM; + tmp.name[sizeof(tmp.name)-1] = 0; newinfo = xt_alloc_table_info(tmp.size); if (!newinfo) @@ -930,6 +931,7 @@ static int do_add_counters(void __user *user, unsigned int len) paddc = vmalloc(len); if (!paddc) return -ENOMEM; + tmp.name[sizeof(tmp.name)-1] = 0; if (copy_from_user(paddc, user, len) != 0) { ret = -EFAULT; @@ -1070,6 +1072,7 @@ static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len ret = -EFAULT; break; } + rev.name[sizeof(rev.name)-1] = 0; try_then_request_module(xt_find_revision(NF_ARP, rev.name, rev.revision, 1, &ret),