From 0ba7536d5d47e4ecf2259a80b207158dc4e711eb Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@cse.unsw.edu.au>
Date: Mon, 7 Nov 2005 01:00:26 -0800
Subject: [PATCH] knfsd: Fix some minor sign problems in nfsd/xdr
There are a couple of tests which could possibly be confused by extremely
large numbers appearing in 'xdr' packets. I think the closest to an exploit
you could get would be writing random data from a free page into a file - i.e.
leak data out of kernel space.
I'm fairly sure they cannot be used for remote compromise.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
fs/nfsd/nfs3xdr.c | 3 ++-
include/linux/nfsd/xdr3.h | 2 +-
include/linux/sunrpc/svc.h | 3 ++-
3 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index e0e134d..9147b85 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -366,7 +366,8 @@ nfs3svc_decode_writeargs(struct svc_rqst *rqstp, u32 *p,
len = args->len = ntohl(*p++);
hdr = (void*)p - rqstp->rq_arg.head[0].iov_base;
- if (rqstp->rq_arg.len < len + hdr)
+ if (rqstp->rq_arg.len < hdr ||
+ rqstp->rq_arg.len - hdr < len)
return 0;
args->vec[0].iov_base = (void*)p;
diff --git a/include/linux/nfsd/xdr3.h b/include/linux/nfsd/xdr3.h
index 21e18ce..3c2a71b 100644
--- a/include/linux/nfsd/xdr3.h
+++ b/include/linux/nfsd/xdr3.h
@@ -42,7 +42,7 @@ struct nfsd3_writeargs {
__u64 offset;
__u32 count;
int stable;
- int len;
+ __u32 len;
struct kvec vec[RPCSVC_MAXPAGES];
int vlen;
};
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 5af8800..e4086ec 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -171,7 +171,8 @@ xdr_argsize_check(struct svc_rqst *rqstp, u32 *p)
{
char *cp = (char *)p;
struct kvec *vec = &rqstp->rq_arg.head[0];
- return cp - (char*)vec->iov_base <= vec->iov_len;
+ return cp >= (char*)vec->iov_base
+ && cp <= (char*)vec->iov_base + vec->iov_len;
}
static inline int
--
cgit v1.1