From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: v9fs-developer@lists.sourceforge.net
Cc: linux-kernel@vger.kernel.org,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Subject: [PATCH] net/9p: Handle error in zero copy request correctly for 9p2000.u
Date: Mon, 20 May 2013 23:05:15 +0530 [thread overview]
Message-ID: <1369071315-26047-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> (raw)
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
For zero copy request, error will be encoded in the user space buffer.
So copy the error code correctly using copy_from_user. Here we use the
extra bytes we allocate for zero copy request. If total error details
are more than P9_ZC_HDR_SZ - 7 bytes, we return -EFAULT. The patch also
avoid a memory allocation in the error path.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
net/9p/client.c | 55 ++++++++++++++++++-------------------------------------
1 file changed, 18 insertions(+), 37 deletions(-)
diff --git a/net/9p/client.c b/net/9p/client.c
index 5e94dab..01f1779 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -562,36 +562,19 @@ static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
if (!p9_is_proto_dotl(c)) {
/* Error is reported in string format */
- uint16_t len;
- /* 7 = header size for RERROR, 2 is the size of string len; */
- int inline_len = in_hdrlen - (7 + 2);
+ int len;
+ /* 7 = header size for RERROR; */
+ int inline_len = in_hdrlen - 7;
- /* Read the size of error string */
- err = p9pdu_readf(req->rc, c->proto_version, "w", &len);
- if (err)
- goto out_err;
-
- ename = kmalloc(len + 1, GFP_NOFS);
- if (!ename) {
- err = -ENOMEM;
+ len = req->rc->size - req->rc->offset;
+ if (len > (P9_ZC_HDR_SZ - 7)) {
+ err = -EFAULT;
goto out_err;
}
- if (len <= inline_len) {
- /* We have error in protocol buffer itself */
- if (pdu_read(req->rc, ename, len)) {
- err = -EFAULT;
- goto out_free;
- }
- } else {
- /*
- * Part of the data is in user space buffer.
- */
- if (pdu_read(req->rc, ename, inline_len)) {
- err = -EFAULT;
- goto out_free;
-
- }
+ ename = &req->rc->sdata[req->rc->offset];
+ if (len > inline_len) {
+ /* We have error in external buffer */
if (kern_buf) {
memcpy(ename + inline_len, uidata,
len - inline_len);
@@ -600,19 +583,19 @@ static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
uidata, len - inline_len);
if (err) {
err = -EFAULT;
- goto out_free;
+ goto out_err;
}
}
}
- ename[len] = 0;
- if (p9_is_proto_dotu(c)) {
- /* For dotu we also have error code */
- err = p9pdu_readf(req->rc,
- c->proto_version, "d", &ecode);
- if (err)
- goto out_free;
+ ename = NULL;
+ 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 (!err || !IS_ERR_VALUE(err)) {
err = p9_errstr2errno(ename, strlen(ename));
@@ -628,8 +611,6 @@ static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
}
return err;
-out_free:
- kfree(ename);
out_err:
p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
return err;
--
1.8.1.2
reply other threads:[~2013-05-20 17:35 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1369071315-26047-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com \
--to=aneesh.kumar@linux.vnet.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=v9fs-developer@lists.sourceforge.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.