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| author | J. Bruce Fields <bfields@redhat.com> | 2014-12-22 16:14:51 -0500 |
|---|---|---|
| committer | J. Bruce Fields <bfields@redhat.com> | 2015-01-07 14:03:58 -0500 |
| commit | 49a068f82a1d30eb585d7804b05948376be6cf9a (patch) | |
| tree | 670d3bc2de3e9faec18f6fbc36f0a997f99a0992 /net/sunrpc/xdr.c | |
| parent | 94ae1db226a5bcbb48372d81161f084c9e283fd8 (diff) | |
| download | linux-49a068f82a1d30eb585d7804b05948376be6cf9a.tar.bz2 | |
rpc: fix xdr_truncate_encode to handle buffer ending on page boundary
A struct xdr_stream at a page boundary might point to the end of one
page or the beginning of the next, but xdr_truncate_encode isn't
prepared to handle the former.
This can cause corruption of NFSv4 READDIR replies in the case that a
readdir entry that would have exceeded the client's dircount/maxcount
limit would have ended exactly on a 4k page boundary. You're more
likely to hit this case on large directories.
Other xdr_truncate_encode callers are probably also affected.
Reported-by: Holger Hoffstätte <holger.hoffstaette@googlemail.com>
Tested-by: Holger Hoffstätte <holger.hoffstaette@googlemail.com>
Fixes: 3e19ce762b53 "rpc: xdr_truncate_encode"
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'net/sunrpc/xdr.c')
| -rw-r--r-- | net/sunrpc/xdr.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index 1cb61242e55e..4439ac4c1b53 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -606,7 +606,7 @@ void xdr_truncate_encode(struct xdr_stream *xdr, size_t len) struct kvec *head = buf->head; struct kvec *tail = buf->tail; int fraglen; - int new, old; + int new; if (len > buf->len) { WARN_ON_ONCE(1); @@ -629,8 +629,8 @@ void xdr_truncate_encode(struct xdr_stream *xdr, size_t len) buf->len -= fraglen; new = buf->page_base + buf->page_len; - old = new + fraglen; - xdr->page_ptr -= (old >> PAGE_SHIFT) - (new >> PAGE_SHIFT); + + xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT); if (buf->page_len) { xdr->p = page_address(*xdr->page_ptr); |