Messages in this thread Patch in this message | | | Date | Mon, 21 Mar 2011 16:06:51 -0700 | From | Greg KH <> | Subject | [52/87] NFS: Fix a decoding problem in nfs3_decode_dirent |
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2.6.37-stable review patch. If anyone has any objections, please let us know.
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[This needs to be applied to 2.6.37 only. The bug in question was inadvertently fixed by a series of cleanups in 2.6.38, but the patches in question are too large to be backported. This patch is a minimal fix that serves the same purpose.]
When we decode a filename followed by an 8-byte cookie, we need to consider the fact that the filename and cookie are 32-bit word aligned. Presently, we may end up copying insufficient amounts of data when xdr_inline_decode() needs to invoke xdr_copy_to_scratch to deal with a page boundary.
The following patch fixes the issue by first decoding the filename, and then decoding the cookie.
Reported-by: Neil Brown <neilb@suse.de> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Reviewed-by: NeilBrown <neilb@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/nfs/nfs2xdr.c | 6 ++++-- fs/nfs/nfs3xdr.c | 6 ++++-- 2 files changed, 8 insertions(+), 4 deletions(-)
--- a/fs/nfs/nfs2xdr.c +++ b/fs/nfs/nfs2xdr.c @@ -477,11 +477,13 @@ nfs_decode_dirent(struct xdr_stream *xdr entry->ino = ntohl(*p++); entry->len = ntohl(*p++); - p = xdr_inline_decode(xdr, entry->len + 4); + p = xdr_inline_decode(xdr, entry->len); if (unlikely(!p)) goto out_overflow; entry->name = (const char *) p; - p += XDR_QUADLEN(entry->len); + p = xdr_inline_decode(xdr, 4); + if (unlikely(!p)) + goto out_overflow; entry->prev_cookie = entry->cookie; entry->cookie = ntohl(*p++); --- a/fs/nfs/nfs3xdr.c +++ b/fs/nfs/nfs3xdr.c @@ -614,11 +614,13 @@ nfs3_decode_dirent(struct xdr_stream *xd p = xdr_decode_hyper(p, &entry->ino); entry->len = ntohl(*p++); - p = xdr_inline_decode(xdr, entry->len + 8); + p = xdr_inline_decode(xdr, entry->len); if (unlikely(!p)) goto out_overflow; entry->name = (const char *) p; - p += XDR_QUADLEN(entry->len); + p = xdr_inline_decode(xdr, 8); + if (unlikely(!p)) + goto out_overflow; entry->prev_cookie = entry->cookie; p = xdr_decode_hyper(p, &entry->cookie);
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