v9fs_walk: As per 9p2000 RFC, MAXWELEM >= nwnames >= 0.

The nwnames field in TWALK message is assumed to be >=0 and <= MAXWELEM
which is defined as macro P9_MAXWELEM (16) in virtio-9p.h as per 9p2000
RFC. Appropriate changes are required in V9fsWalkState and v9fs_walk.

Signed-off-by: Harsh Prateek Bora <harsh@linux.vnet.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
This commit is contained in:
Harsh Prateek Bora 2011-04-14 14:54:40 +05:30 committed by Venkateswararao Jujjuri
parent f35bde2f8f
commit 4f8dee2dec
2 changed files with 6 additions and 3 deletions

View file

@ -1482,7 +1482,7 @@ static void v9fs_walk_complete(V9fsState *s, V9fsWalkState *vs, int err)
{
complete_pdu(s, vs->pdu, err);
if (vs->nwnames) {
if (vs->nwnames && vs->nwnames <= P9_MAXWELEM) {
for (vs->name_idx = 0; vs->name_idx < vs->nwnames; vs->name_idx++) {
v9fs_string_free(&vs->wnames[vs->name_idx]);
}
@ -1578,7 +1578,7 @@ static void v9fs_walk(V9fsState *s, V9fsPDU *pdu)
vs->offset += pdu_unmarshal(vs->pdu, vs->offset, "ddw", &fid,
&newfid, &vs->nwnames);
if (vs->nwnames) {
if (vs->nwnames && vs->nwnames <= P9_MAXWELEM) {
vs->wnames = qemu_mallocz(sizeof(vs->wnames[0]) * vs->nwnames);
vs->qids = qemu_mallocz(sizeof(vs->qids[0]) * vs->nwnames);
@ -1587,6 +1587,9 @@ static void v9fs_walk(V9fsState *s, V9fsPDU *pdu)
vs->offset += pdu_unmarshal(vs->pdu, vs->offset, "s",
&vs->wnames[i]);
}
} else if (vs->nwnames > P9_MAXWELEM) {
err = -EINVAL;
goto out;
}
vs->fidp = lookup_fid(s, fid);

View file

@ -282,7 +282,7 @@ typedef struct V9fsStatStateDotl {
typedef struct V9fsWalkState {
V9fsPDU *pdu;
size_t offset;
int16_t nwnames;
uint16_t nwnames;
int name_idx;
V9fsQID *qids;
V9fsFidState *fidp;