[PATCH] netlink: validate NLA_MSECS length
From: Johannes Berg <johannes@sipsolutions.net>
Date: 2011-11-03 10:07:40
From: Johannes Berg <redacted>
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>
Cc: stable@vger.kernel.org
Signed-off-by: Johannes Berg <redacted>
---
lib/nlattr.c | 1 +
1 file changed, 1 insertion(+)
--- a/lib/nlattr.c 2011-04-29 11:34:55.000000000 +0200
+++ b/lib/nlattr.c 2011-11-03 11:02:10.000000000 +0100@@ -20,6 +20,7 @@ static const u16 nla_attr_minlen[NLA_TYP [NLA_U16] = sizeof(u16), [NLA_U32] = sizeof(u32), [NLA_U64] = sizeof(u64), + [NLA_MSECS] = sizeof(u64), [NLA_NESTED] = NLA_HDRLEN, };