netfilter: ipset: small potential read beyond the end of buffer

PATCH Applied Dan Carpenter 3 participants 7 messages Nov 7, 2014 – Nov 11, 2014

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Dan Carpenter

author

2014-11-07 06:21 UTC #0 lore raw

PATCH 1/1 netfilter: ipset: small potential read beyond the end of buffer

We could be reading 8 bytes into a 4 byte buffer here. It seems harmless but adding a check is the right thing to do and it silences a static checker warning.

Signed-off-by Dan Carpenter <[email protected]>

net/netfilter/ipset/ip_set_core.c +2 -1

index 86f9d76..ac08a3f 100644
@@ -1863,7 +1863,8 @@ ip_set_sockfn_get(struct sock *sk, int optval, void __user *user, int *len)
 	if (*op < IP_SET_OP_VERSION) {
 		/* Check the version at the beginning of operations */
 		struct ip_set_req_version *req_version = data;
-		if (req_version->version != IPSET_PROTOCOL) {
+		if (*len < sizeof(struct ip_set_req_version) ||
+		    req_version->version != IPSET_PROTOCOL) {
 			ret = -EPROTO;
 			goto done;
 		}

Pablo Neira Ayuso

maintainer

2014-11-10 14:22 UTC #1 lore raw

Quoted 11 lines · Dan Carpenter

We could be reading 8 bytes into a 4 byte buffer here. It seems harmless but adding a check is the right thing to do and it silences a static checker warning.
Signed-off-by Dan Carpenter <[email protected]>
net/netfilter/ipset/ip_set_core.c +0 -0
index 86f9d76..ac08a3f 100644

net/netfilter/ipset/ip_set_core.c ip_set_sockfn_get(struct sock *sk, int optval, void __user *user, int *len) · line 1869

Quoted 8 lines

net/netfilter/ipset/ip_set_core.c +2 -1

@@ -1863,7 +1863,8 @@ ip_set_sockfn_get(struct sock *sk, int optval, void __user *user, int *len)
 	if (*op < IP_SET_OP_VERSION) {
 		/* Check the version at the beginning of operations */
 		struct ip_set_req_version *req_version = data;
-		if (req_version->version != IPSET_PROTOCOL) {
+		if (*len < sizeof(struct ip_set_req_version) ||
+		    req_version->version != IPSET_PROTOCOL) {
 			ret = -EPROTO;
 			goto done;

Thanks for catching up this.

Quoted 1 line

From other similar code in that location, I can see Jozsef is using

this pattern:

                if (*len != sizeof(struct ip_set_req_version)) {
                        ret = -EINVAL;
                        goto done;
                }

I think it would be good to stick to that for consistency. Thanks.

Jozsef Kadlecsik

Acked-by

2014-11-10 14:27 UTC #2 lore raw

Quoted 24 lines · Pablo Neira Ayuso

Quoted 11 lines · Dan Carpenter
We could be reading 8 bytes into a 4 byte buffer here. It seems harmless but adding a check is the right thing to do and it silences a static checker warning.
Signed-off-by Dan Carpenter <[email protected]>
net/netfilter/ipset/ip_set_core.c +0 -0
index 86f9d76..ac08a3f 100644
net/netfilter/ipset/ip_set_core.c ip_set_sockfn_get(struct sock *sk, int optval, void __user *user, int *len) · line 1869
Quoted 8 lines
net/netfilter/ipset/ip_set_core.c +2 -1
@@ -1863,7 +1863,8 @@ ip_set_sockfn_get(struct sock *sk, int optval, void __user *user, int *len)
 	if (*op < IP_SET_OP_VERSION) {
 		/* Check the version at the beginning of operations */
 		struct ip_set_req_version *req_version = data;
-		if (req_version->version != IPSET_PROTOCOL) {
+		if (*len < sizeof(struct ip_set_req_version) ||
+		    req_version->version != IPSET_PROTOCOL) {
 			ret = -EPROTO;
 			goto done;
Thanks for catching up this.
Quoted 1 line
From other similar code in that location, I can see Jozsef is using

Quoted 8 lines

this pattern:

                if (*len != sizeof(struct ip_set_req_version)) {
                        ret = -EINVAL;
                        goto done;
                }

I think it would be good to stick to that for consistency. Thanks.

Absolutely, yes.

Acked-by Jozsef Kadlecsik <[email protected]>

Best regards,
Jozsef
-
E-mail : [email protected], [email protected] PGP key : http://www.kfki.hu/~kadlec/pgp_public_key.txt
Address : Wigner Research Centre for Physics, Hungarian Academy of Sciences

          H-1525 Budapest 114, POB. 49, Hungary

Pablo Neira Ayuso

maintainer

2014-11-10 16:09 UTC #3 lore raw

Quoted 9 lines · Jozsef Kadlecsik

Quoted 8 lines · Pablo Neira Ayuso
Quoted 1 line
From other similar code in that location, I can see Jozsef is using
this pattern:
                if (*len != sizeof(struct ip_set_req_version)) {
                        ret = -EINVAL;
                        goto done;
                }

Quoted 5 lines

Quoted 1 line
I think it would be good to stick to that for consistency. Thanks.
Absolutely, yes.
Acked-by Jozsef Kadlecsik <[email protected]>

OK, then does this look fine to you? I took over Dan's patch and gave it another spin. See it attached, thanks.

Quoted 1 line

From d67bad383d4ea9dea8872e3999324ccbeb2a5815 Mon Sep 17 00:00:00 2001

From: Dan Carpenter <[email protected]>
Date: Fri, 7 Nov 2014 09:21:40 +0300
Subject: [PATCH] netfilter: ipset: small potential read beyond the end of
buffer

We could be reading 8 bytes into a 4 byte buffer here. It seems harmless but adding a check is the right thing to do and it silences a static checker warning.

Signed-off-by Dan Carpenter <[email protected]>

Signed-off-by Pablo Neira Ayuso <[email protected]>

---
 net/netfilter/ipset/ip_set_core.c |    6 ++++++
 1 file changed, 6 insertions(+)

net/netfilter/ipset/ip_set_core.c +6 -0

index 86f9d76..d259da3 100644
@@ -1863,6 +1863,12 @@ ip_set_sockfn_get(struct sock *sk, int optval, void __user *user, int *len)
 	if (*op < IP_SET_OP_VERSION) {
 		/* Check the version at the beginning of operations */
 		struct ip_set_req_version *req_version = data;
+
+		if (*len < sizeof(struct ip_set_req_version)) {
+			ret = -EINVAL;
+			goto done;
+		}
+
 		if (req_version->version != IPSET_PROTOCOL) {
 			ret = -EPROTO;
 			goto done;

Signature · 1 line

1.7.10.4

Jozsef Kadlecsik

2014-11-10 20:59 UTC #4 lore raw

Quoted 10 lines · Pablo Neira Ayuso

Quoted 9 lines · Jozsef Kadlecsik
Quoted 8 lines · Pablo Neira Ayuso
Quoted 1 line
From other similar code in that location, I can see Jozsef is using
this pattern:
                if (*len != sizeof(struct ip_set_req_version)) {
                        ret = -EINVAL;
                        goto done;
                }

Quoted 8 lines

Quoted 5 lines
Quoted 1 line
I think it would be good to stick to that for consistency. Thanks.
Absolutely, yes.
Acked-by Jozsef Kadlecsik <[email protected]>
OK, then does this look fine to you? I took over Dan's patch and gave it another spin. See it attached, thanks.

Yes, it's better this way, thanks!

          H-1525 Budapest 114, POB. 49, Hungary

Pablo Neira Ayuso

maintainer Applied

2014-11-11 13:15 UTC #5 lore raw

Quoted 14 lines · Jozsef Kadlecsik

Quoted 12 lines · Pablo Neira Ayuso
Quoted 11 lines · Jozsef Kadlecsik
Quoted 9 lines · Pablo Neira Ayuso
Quoted 1 line
From other similar code in that location, I can see Jozsef is using
this pattern:
                if (*len != sizeof(struct ip_set_req_version)) {
                        ret = -EINVAL;
                        goto done;
                }
I think it would be good to stick to that for consistency. Thanks.

Quoted 8 lines

Quoted 6 lines
Quoted 3 lines
Absolutely, yes.
Acked-by Jozsef Kadlecsik <[email protected]>
OK, then does this look fine to you? I took over Dan's patch and gave it another spin. See it attached, thanks.
Yes, it's better this way, thanks!

Applied, thanks Dan and Jozsef.

Dan Carpenter

author

2014-11-10 22:38 UTC #6 lore raw

In reply to Pablo Neira Ayuso

Quoted 2 lines · Pablo Neira Ayuso

OK, then does this look fine to you? I took over Dan's patch and gave it another spin. See it attached, thanks.

Looks good to me, thanks.

regards,
dan carpenter