diff options
| author | Trond Myklebust <Trond.Myklebust@netapp.com> | 2012-08-14 17:30:10 -0400 |
|---|---|---|
| committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2012-08-16 16:15:50 -0400 |
| commit | 519d3959e30a98f8e135e7a16647c10af5ad63d5 (patch) | |
| tree | 95d4ba3b32892b4145f6054684102c83aca65025 | |
| parent | 425e776d93a7a5070b77d4f458a5bab0f924652c (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
| -rw-r--r-- | fs/nfs/nfs4proc.c | 2 | ||||
| -rw-r--r-- | fs/nfs/nfs4xdr.c | 21 |
2 files changed, 8 insertions, 15 deletions
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index c77d296bdaa..286ab707841 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -3819,7 +3819,7 @@ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t bu if (ret) goto out_free; - acl_len = res.acl_len - res.acl_data_offset; + acl_len = res.acl_len; if (acl_len > args.acl_len) nfs4_write_cached_acl(inode, NULL, 0, acl_len); else diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c index ca13483edd6..54d3f5a9faa 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; |