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tools/kvm/9p: check the iov count with the read/write count

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Make sure we don't read/write more than what is requested
from client.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
This commit is contained in:
Aneesh Kumar K.V
2011-06-19 15:14:35 +05:30
committed by Will Deacon
parent af045e53d1
commit 6b163a8729
1 changed files with 21 additions and 0 deletions
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virtio/9p.c
+21
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@@ -194,6 +194,22 @@ 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)
{
@@ -445,6 +461,9 @@ 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)
@@ -549,6 +568,8 @@ 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);