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authorDavid Howells <dhowells@redhat.com>2006-08-24 15:44:19 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2006-08-24 15:53:34 -0400
commite8896495bca8490a427409e0886d63d05419ec65 (patch)
treeb402c7c7a868501e3c6dbcf1874ead3368152ea4
parent3cedf13af9f7e61aca0dbbd11b601ac93bf93a9f (diff)
downloadlinux-stericsson-e8896495bca8490a427409e0886d63d05419ec65.tar.gz
NFS: Check lengths more thoroughly in NFS4 readdir XDR decode
Check the bounds of length specifiers more thoroughly in the XDR decoding of NFS4 readdir reply data. Currently, if the server returns a bitmap or attr length that causes the current decode point pointer to wrap, this could go undetected (consider a small "negative" length on a 32-bit machine). Also add a check into the main XDR decode handler to make sure that the amount of data is a multiple of four bytes (as specified by RFC-1014). This makes sure that we can do u32* pointer subtraction in the NFS client without risking an undefined result (the result is undefined if the pointers are not correctly aligned with respect to one another). Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> (cherry picked from 5861fddd64a7eaf7e8b1a9997455a24e7f688092 commit)
-rw-r--r--fs/nfs/nfs4xdr.c21
-rw-r--r--net/sunrpc/clnt.c11
2 files changed, 22 insertions, 10 deletions
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 1750d996f49f..730ec8fb31c6 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -3355,7 +3355,7 @@ static int decode_readdir(struct xdr_stream *xdr, struct rpc_rqst *req, struct n
struct kvec *iov = rcvbuf->head;
unsigned int nr, pglen = rcvbuf->page_len;
uint32_t *end, *entry, *p, *kaddr;
- uint32_t len, attrlen;
+ uint32_t len, attrlen, xlen;
int hdrlen, recvd, status;
status = decode_op_hdr(xdr, OP_READDIR);
@@ -3377,10 +3377,10 @@ static int decode_readdir(struct xdr_stream *xdr, struct rpc_rqst *req, struct n
BUG_ON(pglen + readdir->pgbase > PAGE_CACHE_SIZE);
kaddr = p = (uint32_t *) kmap_atomic(page, KM_USER0);
- end = (uint32_t *) ((char *)p + pglen + readdir->pgbase);
+ end = p + ((pglen + readdir->pgbase) >> 2);
entry = p;
for (nr = 0; *p++; nr++) {
- if (p + 3 > end)
+ if (end - p < 3)
goto short_pkt;
dprintk("cookie = %Lu, ", *((unsigned long long *)p));
p += 2; /* cookie */
@@ -3389,18 +3389,19 @@ static int decode_readdir(struct xdr_stream *xdr, struct rpc_rqst *req, struct n
printk(KERN_WARNING "NFS: giant filename in readdir (len 0x%x)\n", len);
goto err_unmap;
}
- dprintk("filename = %*s\n", len, (char *)p);
- p += XDR_QUADLEN(len);
- if (p + 1 > end)
+ xlen = XDR_QUADLEN(len);
+ if (end - p < xlen + 1)
goto short_pkt;
+ dprintk("filename = %*s\n", len, (char *)p);
+ p += xlen;
len = ntohl(*p++); /* bitmap length */
- p += len;
- if (p + 1 > end)
+ if (end - p < len + 1)
goto short_pkt;
+ p += len;
attrlen = XDR_QUADLEN(ntohl(*p++));
- p += attrlen; /* attributes */
- if (p + 2 > end)
+ if (end - p < attrlen + 2)
goto short_pkt;
+ p += attrlen; /* attributes */
entry = p;
}
if (!nr && (entry[0] != 0 || entry[1] == 0))
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index d9eac7069101..3e19d321067a 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1181,6 +1181,17 @@ call_verify(struct rpc_task *task)
u32 *p = iov->iov_base, n;
int error = -EACCES;
+ if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
+ /* RFC-1014 says that the representation of XDR data must be a
+ * multiple of four bytes
+ * - if it isn't pointer subtraction in the NFS client may give
+ * undefined results
+ */
+ printk(KERN_WARNING
+ "call_verify: XDR representation not a multiple of"
+ " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
+ goto out_eio;
+ }
if ((len -= 3) < 0)
goto out_overflow;
p += 1; /* skip XID */