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authorTrond Myklebust <Trond.Myklebust@netapp.com>2012-08-14 17:30:10 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2012-08-16 16:15:50 -0400
commit519d3959e30a98f8e135e7a16647c10af5ad63d5 (patch)
tree95d4ba3b32892b4145f6054684102c83aca65025 /fs/nfs/nfs4xdr.c
parent425e776d93a7a5070b77d4f458a5bab0f924652c (diff)
NFSv4: Fix pointer arithmetic in decode_getacl
Resetting the cursor xdr->p to a previous value is not a safe practice: if the xdr_stream has crossed out of the initial iovec, then a bunch of other fields would need to be reset too. Fix this issue by using xdr_enter_page() so that the buffer gets page aligned at the bitmap _before_ we decode it. Also fix the confusion of the ACL length with the page buffer length by not adding the base offset to the ACL length... Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: stable@vger.kernel.org
Diffstat (limited to 'fs/nfs/nfs4xdr.c')
-rw-r--r--fs/nfs/nfs4xdr.c21
1 files changed, 7 insertions, 14 deletions
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index ca13483edd60..54d3f5a9faa6 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -5049,18 +5049,14 @@ static int decode_getacl(struct xdr_stream *xdr, struct rpc_rqst *req,
uint32_t attrlen,
bitmap[3] = {0};
int status;
- size_t page_len = xdr->buf->page_len;
res->acl_len = 0;
if ((status = decode_op_hdr(xdr, OP_GETATTR)) != 0)
goto out;
+ xdr_enter_page(xdr, xdr->buf->page_len);
+
bm_p = xdr->p;
- res->acl_data_offset = be32_to_cpup(bm_p) + 2;
- res->acl_data_offset <<= 2;
- /* Check if the acl data starts beyond the allocated buffer */
- if (res->acl_data_offset > page_len)
- return -ERANGE;
if ((status = decode_attr_bitmap(xdr, bitmap)) != 0)
goto out;
@@ -5074,23 +5070,20 @@ static int decode_getacl(struct xdr_stream *xdr, struct rpc_rqst *req,
/* The bitmap (xdr len + bitmaps) and the attr xdr len words
* are stored with the acl data to handle the problem of
* variable length bitmaps.*/
- xdr->p = bm_p;
+ res->acl_data_offset = (xdr->p - bm_p) << 2;
/* We ignore &savep and don't do consistency checks on
* the attr length. Let userspace figure it out.... */
- attrlen += res->acl_data_offset;
- if (attrlen > page_len) {
+ res->acl_len = attrlen;
+ if (attrlen + res->acl_data_offset > xdr->buf->page_len) {
if (res->acl_flags & NFS4_ACL_LEN_REQUEST) {
/* getxattr interface called with a NULL buf */
- res->acl_len = attrlen;
goto out;
}
- dprintk("NFS: acl reply: attrlen %u > page_len %zu\n",
- attrlen, page_len);
+ dprintk("NFS: acl reply: attrlen %u > page_len %u\n",
+ attrlen, xdr->buf->page_len);
return -EINVAL;
}
- xdr_read_pages(xdr, attrlen);
- res->acl_len = attrlen;
} else
status = -EOPNOTSUPP;