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 <[email protected]> Signed-off-by: Trond Myklebust <[email protected]> Reviewed-by: NeilBrown <[email protected]> --- Hi Greg, 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. fs/nfs/nfs2xdr.c | 6 ++++-- fs/nfs/nfs3xdr.c | 6 ++++-- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c index b382a1b..33a038d 100644 --- a/fs/nfs/nfs2xdr.c +++ b/fs/nfs/nfs2xdr.c @@ -477,11 +477,13 @@ nfs_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry, struct nfs_se 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++); diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c index ba91236..dcd934f 100644 --- a/fs/nfs/nfs3xdr.c +++ b/fs/nfs/nfs3xdr.c @@ -614,11 +614,13 @@ nfs3_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry, struct nfs_s 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); -- 1.7.4 _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
