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    Subject[PATCH] [31/106] netfilter: arp_tables: fix infoleak to userspace
    Date
    2.6.35-longterm review patch.  If anyone has any objections, please let me know.

    ------------------
    From: Vasiliy Kulikov <segoon@openwall.com>

    commit 42eab94fff18cb1091d3501cd284d6bd6cc9c143 upstream.

    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 <segoon@openwall.com>
    Signed-off-by: Patrick McHardy <kaber@trash.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
    Signed-off-by: Andi Kleen <ak@linux.intel.com>

    ---
    net/ipv4/netfilter/arp_tables.c | 3 +++
    1 file changed, 3 insertions(+)

    Index: linux-2.6.35.y/net/ipv4/netfilter/arp_tables.c
    ===================================================================
    --- linux-2.6.35.y.orig/net/ipv4/netfilter/arp_tables.c
    +++ linux-2.6.35.y/net/ipv4/netfilter/arp_tables.c
    @@ -1081,6 +1081,7 @@ static int do_replace(struct net *net, c
    /* overflow check */
    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)
    @@ -1502,6 +1503,7 @@ static int compat_do_replace(struct net
    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)
    @@ -1754,6 +1756,7 @@ static int do_arpt_get_ctl(struct sock *
    ret = -EFAULT;
    break;
    }
    + rev.name[sizeof(rev.name)-1] = 0;

    try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
    rev.revision, 1, &ret),

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