This is a rather sticky issue to deal with in non-9P2000.L protocols.
In 9P2000.L, the error is a fixed size (errno) hence not an issue.
But for other protocols it is a string of size (ERRMAX).
To take care of TREAD/RERROR scenario in !dotl this change makes sure that
the read buffer is big enough to accommodate ERRMAX string.
It also means that there is a chance of scribbling on the payload/user
buffer in the error case for those non-POSIX complaint protocols.
Signed-off-by: Venkateswararao Jujjuri <jvrao@xxxxxxxxxxxxxxxxxx>
---
net/9p/client.c | 64 +++++++++++++++++++++++++++++++++++-------------------
1 files changed, 41 insertions(+), 23 deletions(-)
diff --git a/net/9p/client.c b/net/9p/client.c
index 412c52e..f00ca1f 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -443,6 +443,7 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
{
int8_t type;
int err;
+ int ecode;
err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
if (err) {
@@ -450,36 +451,53 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
return err;
}
- if (type == P9_RERROR || type == P9_RLERROR) {
- int ecode;
-
- if (!p9_is_proto_dotl(c)) {
- char *ename;
+ if (type != P9_RERROR && type != P9_RLERROR)
+ return 0;
- err = p9pdu_readf(req->rc, c->proto_version, "s?d",
- &ename, &ecode);
- if (err)
- goto out_err;
+ if (!p9_is_proto_dotl(c)) {
+ char *ename;
+
+ if (req->tc->pbuf_size) {
+ /* Handle user buffers */
+ size_t len = req->rc->size - req->rc->offset;
+ if (req->tc->pubuf) {
+ /* User Buffer */
+ err = copy_from_user(
+ &req->rc->sdata[req->rc->offset],
+ req->tc->pubuf, len);
+ if (err) {
+ err = -EFAULT;
+ goto out_err;
+ }
+ } else {
+ /* Kernel Buffer */
+ memmove(&req->rc->sdata[req->rc->offset],
+ req->tc->pkbuf, len);
+ }
+ }
+ err = p9pdu_readf(req->rc, c->proto_version, "s?d",
+ &ename, &ecode);
+ if (err)
+ goto out_err;
- if (p9_is_proto_dotu(c))
- err = -ecode;
+ if (p9_is_proto_dotu(c))
+ err = -ecode;
- if (!err || !IS_ERR_VALUE(err)) {
- err = p9_errstr2errno(ename, strlen(ename));
+ if (!err || !IS_ERR_VALUE(err)) {
+ err = p9_errstr2errno(ename, strlen(ename));
- P9_DPRINTK(P9_DEBUG_9P, "<<< RERROR (%d) %s\n", -ecode, ename);
+ P9_DPRINTK(P9_DEBUG_9P, "<<< RERROR (%d) %s\n", -ecode,
+ ename);
- kfree(ename);
- }
- } else {
- err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
- err = -ecode;
-
- P9_DPRINTK(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
+ kfree(ename);
}
+ } else {
+ err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
+ err = -ecode;
+
+ P9_DPRINTK(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
+ }
- } else
- err = 0;
return err;
--
1.6.5.2
--
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