From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
If you see a problem with using this for longterm, please comment.
-------------------
commit d5f50b0c290431c65377c4afa1c764e2c3fe5305 upstream.
If the argument and reply together exceed the maximum payload size, then
a reply with a read-like operation can overlow the rq_pages array.
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
fs/nfsd/nfs4xdr.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 28d586a5e77e..3800e7680037 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2607,11 +2607,16 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
len = maxcount;
v = 0;
while (len > 0) {
- pn = resp->rqstp->rq_resused++;
+ pn = resp->rqstp->rq_resused;
+ if (!resp->rqstp->rq_respages[pn]) { /* ran out of pages */
+ maxcount -= len;
+ break;
+ }
resp->rqstp->rq_vec[v].iov_base =
page_address(resp->rqstp->rq_respages[pn]);
resp->rqstp->rq_vec[v].iov_len =
len < PAGE_SIZE ? len : PAGE_SIZE;
+ resp->rqstp->rq_resused++;
v++;
len -= PAGE_SIZE;
}
@@ -2659,6 +2664,8 @@ nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd
return nfserr;
if (resp->xbuf->page_len)
return nfserr_resource;
+ if (!resp->rqstp->rq_respages[resp->rqstp->rq_resused])
+ return nfserr_resource;
page = page_address(resp->rqstp->rq_respages[resp->rqstp->rq_resused++]);
@@ -2708,6 +2715,8 @@ nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
return nfserr;
if (resp->xbuf->page_len)
return nfserr_resource;
+ if (!resp->rqstp->rq_respages[resp->rqstp->rq_resused])
+ return nfserr_resource;
RESERVE_SPACE(8); /* verifier */
savep = p;
--
1.8.5.2
--
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