| From | Paul Gortmaker <> | Subject | [v2.6.34-stable 123/165] netlink: validate NLA_MSECS length | Date | Wed, 15 Aug 2012 15:47:47 -0400 |
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From: Johannes Berg <johannes.berg@intel.com>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git If you see a problem with using this for longterm, please comment. -------------------
commit c30bc94758ae2a38a5eb31767c1985c0aae0950b upstream.
L2TP for example uses NLA_MSECS like this: policy: [L2TP_ATTR_RECV_TIMEOUT] = { .type = NLA_MSECS, }, code: if (info->attrs[L2TP_ATTR_RECV_TIMEOUT]) cfg.reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
As nla_get_msecs() is essentially nla_get_u64() plus the conversion to a HZ-based value, this will not properly reject attributes from userspace that aren't long enough and might overrun the message.
Add NLA_MSECS to the attribute minlen array to check the size properly.
Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- lib/nlattr.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/lib/nlattr.c b/lib/nlattr.c index c4706eb..109d4fe 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -20,6 +20,7 @@ static u16 nla_attr_minlen[NLA_TYPE_MAX+1] __read_mostly = { [NLA_U16] = sizeof(u16), [NLA_U32] = sizeof(u32), [NLA_U64] = sizeof(u64), + [NLA_MSECS] = sizeof(u64), [NLA_NESTED] = NLA_HDRLEN, }; -- 1.7.12.rc2
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