The patch titled
NFS: Check lengths more thoroughly in NFS4 readdir XDR decode
has been added to the -mm tree. Its filename is
nfs-check-lengths-more-thoroughly-in-nfs4-readdir-xdr-decode.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: NFS: Check lengths more thoroughly in NFS4 readdir XDR decode
From: David Howells <dhowells@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: Trond Myklebust <trond.myklebust@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
fs/nfs/nfs4xdr.c | 22 +++++++++++-----------
net/sunrpc/clnt.c | 11 +++++++++++
2 files changed, 22 insertions(+), 11 deletions(-)
diff -puN fs/nfs/nfs4xdr.c~nfs-check-lengths-more-thoroughly-in-nfs4-readdir-xdr-decode fs/nfs/nfs4xdr.c
--- a/fs/nfs/nfs4xdr.c~nfs-check-lengths-more-thoroughly-in-nfs4-readdir-xdr-decode
+++ a/fs/nfs/nfs4xdr.c
@@ -3355,7 +3355,7 @@ static int decode_readdir(struct xdr_str
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);
@@ -3374,13 +3374,12 @@ static int decode_readdir(struct xdr_str
if (pglen > recvd)
pglen = recvd;
xdr_read_pages(xdr, pglen);
-
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 +3388,19 @@ static int decode_readdir(struct xdr_str
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)
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)
goto short_pkt;
+ p += len;
attrlen = XDR_QUADLEN(ntohl(*p++));
- p += attrlen; /* attributes */
- if (p + 2 > end)
+ if (end - p < attrlen + 1)
goto short_pkt;
+ p += attrlen; /* attributes */
entry = p;
}
if (!nr && (entry[0] != 0 || entry[1] == 0))
diff -puN net/sunrpc/clnt.c~nfs-check-lengths-more-thoroughly-in-nfs4-readdir-xdr-decode net/sunrpc/clnt.c
--- a/net/sunrpc/clnt.c~nfs-check-lengths-more-thoroughly-in-nfs4-readdir-xdr-decode
+++ a/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 */
_
Patches currently in -mm which might be from dhowells@xxxxxxxxxx are
git-gfs2.patch
git-nfs.patch
nfs-replace-null-dentries-that-appear-in-readdirs-list-2.patch
nfs-fix-up-warnings.patch
nfs-check-lengths-more-thoroughly-in-nfs4-readdir-xdr-decode.patch
binfmt_elf-consistently-use-loff_t.patch
afs-add-lock-annotations-to-afs_proc_cell_servers_startstop.patch
elf_fdpic_core_dump-dont-take-tasklist_lock.patch
reiserfs-make-sure-all-dentries-refs-are-released-before-calling-kill_block_super-try-2.patch
fs-cache-provide-a-filesystem-specific-syncable-page-bit.patch
fs-cache-generic-filesystem-caching-facility.patch
fs-cache-release-page-private-in-failed-readahead.patch
fs-cache-release-page-private-after-failed-readahead-12.patch
fs-cache-make-kafs-use-fs-cache.patch
fs-cache-make-kafs-use-fs-cache-fix.patch
fs-cache-make-kafs-use-fs-cache-12.patch
fs-cache-make-kafs-use-fs-cache-12-fix.patch
fs-cache-make-kafs-use-fs-cache-vs-streamline-generic_file_-interfaces-and-filemap.patch
nfs-use-local-caching.patch
nfs-use-local-caching-12.patch
nfs-use-local-caching-12-fix.patch
fs-cache-cachefiles-ia64-missing-copy_page-export.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem-cachefiles-printk-format-warning.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem-warning-fixes.patch
autofs-make-sure-all-dentries-refs-are-released-before-calling-kill_anon_super.patch
vfs-destroy-the-dentries-contributed-by-a-superblock-on-unmounting.patch
vfs-make-filldir_t-and-struct-kstat-deal-in-64-bit-inode-numbers.patch
vfs-make-filldir_t-and-struct-kstat-deal-in-64-bit-inode-numbers-alpha-fix.patch
nfs-represent-64-bit-fileids-as-64-bit-inode-numbers-on-32-bit-systems.patch
ecryptfs-get_sb_dev-fix.patch
reiser4-get_sb_dev-fix.patch
mutex-subsystem-synchro-test-module.patch
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