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Commit 5c0a0fc8 authored by Ying Xue's avatar Ying Xue Committed by David S. Miller
Browse files

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: default avatarYing Xue <ying.xue@windriver.com>
Reviewed-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7cc7c5e5

net/tipc/msg.c

+9 −13
Original line number Diff line number Diff line
@@ -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;

	}

	if (likely(res))

		return dsz;



	to = (*buf)->data + hsz;

	if (total_len && memcpy_fromiovecend(to, msg_sect, 0, dsz)) {

		kfree_skb(*buf);

		*buf = NULL;

		return -EFAULT;

	}

	return dsz;

}