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authorYing Xue <ying.xue@windriver.com>2013-10-18 07:23:14 +0200
committerDavid S. Miller <davem@davemloft.net>2013-10-18 13:20:42 -0400
commit5c0a0fc81f4dc786b42c4fc9c7c72ba635406ab5 (patch)
treedf4a2c33ac2bfda18393fe56500fd0cb58551351
parent7cc7c5e54b7128195a1403747a63971c3c3f8e25 (diff)
tipc: don't use memcpy to copy from user space
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@windriver.com> Reviewed-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/tipc/msg.c22
1 files changed, 9 insertions, 13 deletions
diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index ced60e2fc4f7..1e76d91e5691 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;
}