[PATCH] ipvs: Add boundary check on ioctl arguments

[Arjan van de Ven]

The ipvs code has a nifty system for doing the size of ioctl command copies;
it defines an array with values into which it indexes the cmd to find the
right length.

Unfortunately, the ipvs code forgot to check if the cmd was in the range
that the array provides, allowing for an index outside of the array,
which then gives a "garbage" result into the length, which then gets
used for copying into a stack buffer.

Fix this by adding sanity checks on these as well as the copy size.

Signed-off-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
---
 net/netfilter/ipvs/ip_vs_ctl.c |   14 +++++++++++++-
 1 files changed, 13 insertions(+), 1 deletions(-)

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index ac624e5..3c52796 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -2077,6 +2077,10 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
 	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
 
+	if (cmd < IP_VS_BASE_CTL || cmd > IP_VS_SO_SET_MAX + 1)
+		return -EINVAL;
+	if (len < 0 || len >  MAX_ARG_LEN)
+		return -EINVAL;
 	if (len != set_arglen[SET_CMDID(cmd)]) {
 		pr_err("set_ctl: len %u != %u\n",
 		       len, set_arglen[SET_CMDID(cmd)]);
@@ -2353,17 +2357,25 @@ do_ip_vs_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
 {
 	unsigned char arg[128];
 	int ret = 0;
+	unsigned int copylen;
 
 	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
 
+	if (cmd < IP_VS_BASE_CTL || cmd > IP_VS_SO_GET_MAX + 1)
+		return -EINVAL;
+
 	if (*len < get_arglen[GET_CMDID(cmd)]) {
 		pr_err("get_ctl: len %u < %u\n",
 		       *len, get_arglen[GET_CMDID(cmd)]);
 		return -EINVAL;
 	}
 
-	if (copy_from_user(arg, user, get_arglen[GET_CMDID(cmd)]) != 0)
+	copylen = get_arglen[GET_CMDID(cmd)];
+	if (copylen > 128)
+		return -EINVAL;
+
+	if (copy_from_user(arg, user, copylen) != 0)
 		return -EFAULT;
 
 	if (mutex_lock_interruptible(&__ip_vs_mutex))
-- 
1.6.2.5


-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/