Make sure we don't read/write more than what is requested
from client.
Signed-off-by: Aneesh Kumar K.V <[email protected]>
---
I am not sure whether we really need this. But seems to be a good
check to make sure we don't read/write more
tools/kvm/virtio/9p.c | 21 +++++++++++++++++++++
1 files changed, 21 insertions(+), 0 deletions(-)
diff --git a/tools/kvm/virtio/9p.c b/tools/kvm/virtio/9p.c
index ba5dd7c..558a713 100644
--- a/tools/kvm/virtio/9p.c
+++ b/tools/kvm/virtio/9p.c
@@ -193,6 +193,22 @@ static void set_p9msg_hdr(struct p9_msg *msg, u32 size, u8
cmd, u16 tag)
};
}
+static u16 virtio_p9_update_iov_cnt(struct iovec iov[], u32 count, int iov_cnt)
+{
+ int i;
+ u32 total = 0;
+ for (i = 0; (i < iov_cnt) && (total < count); i++) {
+ if (total + iov[i].iov_len > count) {
+ /* we don't need this iov fully */
+ iov[i].iov_len -= ((total + iov[i].iov_len) - count);
+ i++;
+ break;
+ }
+ total += iov[i].iov_len;
+ }
+ return i;
+}
+
static bool virtio_p9_version(struct p9_dev *p9dev,
struct p9_pdu *pdu, u32 *outlen)
{
@@ -444,6 +460,9 @@ static bool virtio_p9_read(struct p9_dev *p9dev,
} else {
pdu->in_iov[0].iov_base += VIRTIO_P9_HDR_LEN + sizeof(u32);
pdu->in_iov[0].iov_len -= VIRTIO_P9_HDR_LEN + sizeof(u32);
+ pdu->in_iov_cnt = virtio_p9_update_iov_cnt(pdu->in_iov,
+ tread->count,
+ pdu->in_iov_cnt);
rread->count = preadv(fid->fd, pdu->in_iov,
pdu->in_iov_cnt, tread->offset);
if (rread->count > tread->count)
@@ -548,6 +567,8 @@ static bool virtio_p9_write(struct p9_dev *p9dev,
pdu->out_iov[0].iov_base += (sizeof(*outmsg) + sizeof(*twrite));
pdu->out_iov[0].iov_len -= (sizeof(*outmsg) + sizeof(*twrite));
+ pdu->out_iov_cnt = virtio_p9_update_iov_cnt(pdu->out_iov, twrite->count,
+ pdu->out_iov_cnt);
rwrite->count = pwritev(fid->fd, pdu->out_iov,
pdu->out_iov_cnt, twrite->offset);
*outlen = VIRTIO_P9_HDR_LEN + sizeof(u32);
--
1.7.4.1
--
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