| From fd933d047f2c198484a337878787dfde40c8264f Mon Sep 17 00:00:00 2001 |
| From: "J. Bruce Fields" <bfields@redhat.com> |
| Date: Fri, 21 Apr 2017 15:26:30 -0400 |
| Subject: [PATCH] nfsd: stricter decoding of write-like NFSv2/v3 ops |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| commit 13bf9fbff0e5e099e2b6f003a0ab8ae145436309 upstream. |
| |
| The NFSv2/v3 code does not systematically check whether we decode past |
| the end of the buffer. This generally appears to be harmless, but there |
| are a few places where we do arithmetic on the pointers involved and |
| don't account for the possibility that a length could be negative. Add |
| checks to catch these. |
| |
| Reported-by: Tuomas Haanpää <thaan@synopsys.com> |
| Reported-by: Ari Kauppi <ari@synopsys.com> |
| Reviewed-by: NeilBrown <neilb@suse.com> |
| Cc: stable@vger.kernel.org |
| Signed-off-by: J. Bruce Fields <bfields@redhat.com> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c |
| index d18cfddbe115..452334694a5d 100644 |
| --- a/fs/nfsd/nfs3xdr.c |
| +++ b/fs/nfsd/nfs3xdr.c |
| @@ -369,6 +369,8 @@ nfs3svc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p, |
| args->count = ntohl(*p++); |
| args->stable = ntohl(*p++); |
| len = args->len = ntohl(*p++); |
| + if ((void *)p > head->iov_base + head->iov_len) |
| + return 0; |
| /* |
| * The count must equal the amount of data passed. |
| */ |
| @@ -472,6 +474,8 @@ nfs3svc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p, |
| /* first copy and check from the first page */ |
| old = (char*)p; |
| vec = &rqstp->rq_arg.head[0]; |
| + if ((void *)old > vec->iov_base + vec->iov_len) |
| + return 0; |
| avail = vec->iov_len - (old - (char*)vec->iov_base); |
| while (len && avail && *old) { |
| *new++ = *old++; |
| diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c |
| index 59bd88a23a3d..de07ff625777 100644 |
| --- a/fs/nfsd/nfsxdr.c |
| +++ b/fs/nfsd/nfsxdr.c |
| @@ -302,6 +302,8 @@ nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p, |
| * bytes. |
| */ |
| hdr = (void*)p - head->iov_base; |
| + if (hdr > head->iov_len) |
| + return 0; |
| dlen = head->iov_len + rqstp->rq_arg.page_len - hdr; |
| |
| /* |
| -- |
| 2.12.0 |
| |