netdev - [PATCH net-next v2 1/8] tipc: don't use memcpy to copy from user space

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1382073801-22128-2-git-send-email-jon.maloy@ericsson.com>
Date:	Fri, 18 Oct 2013 07:23:14 +0200
From:	Jon Maloy <jon.maloy@...csson.com>
To:	davem@...emloft.net
Cc:	netdev@...r.kernel.org,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	erik.hugne@...csson.com, ying.xue@...driver.com, maloy@...jonn.com,
	tipc-discussion@...ts.sourceforge.net,
	Jon Maloy <jon.maloy@...csson.com>
Subject: [PATCH net-next v2 1/8] tipc: don't use memcpy to copy from user space

From: Ying Xue <ying.xue@...driver.com>

tipc_msg_build() calls skb_copy_to_linear_data_offset() to copy data
from user space to kernel space. However, the latter function does
in its turn call memcpy() to perform the actual copying. This poses
an obvious security and robustness risk, since memcpy() never makes
any validity check on the pointer it is copying from.

To correct this, we the replace the offending function call with
a call to memcpy_fromiovecend(), which uses copy_from_user() to
perform the copying.

Signed-off-by: Ying Xue <ying.xue@...driver.com>
Reviewed-by: Paul Gortmaker <paul.gortmaker@...driver.com>
Signed-off-by: Jon Maloy <jon.maloy@...csson.com>
---
 net/tipc/msg.c |   22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index ced60e2..1e76d91 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -76,10 +76,11 @@ int tipc_msg_build(struct tipc_msg *hdr, struct iovec const *msg_sect,
 		   u32 num_sect, unsigned int total_len, int max_size,
 		   struct sk_buff **buf)
 {
-	int dsz, sz, hsz, pos, res, cnt;
+	int dsz, sz, hsz;
+	unsigned char *to;
 
 	dsz = total_len;
-	pos = hsz = msg_hdr_sz(hdr);
+	hsz = msg_hdr_sz(hdr);
 	sz = hsz + dsz;
 	msg_set_size(hdr, sz);
 	if (unlikely(sz > max_size)) {
@@ -91,16 +92,11 @@ int tipc_msg_build(struct tipc_msg *hdr, struct iovec const *msg_sect,
 	if (!(*buf))
 		return -ENOMEM;
 	skb_copy_to_linear_data(*buf, hdr, hsz);
-	for (res = 1, cnt = 0; res && (cnt < num_sect); cnt++) {
-		skb_copy_to_linear_data_offset(*buf, pos,
-					       msg_sect[cnt].iov_base,
-					       msg_sect[cnt].iov_len);
-		pos += msg_sect[cnt].iov_len;
+	to = (*buf)->data + hsz;
+	if (total_len && memcpy_fromiovecend(to, msg_sect, 0, dsz)) {
+		kfree_skb(*buf);
+		*buf = NULL;
+		return -EFAULT;
 	}
-	if (likely(res))
-		return dsz;
-
-	kfree_skb(*buf);
-	*buf = NULL;
-	return -EFAULT;
+	return dsz;
 }
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html