From 62d98c935456ee121b03d6a68aa3091a04085b7e Mon Sep 17 00:00:00 2001 From: NeilBrown <neilb@suse.de> Date: Mon, 17 Sep 2012 16:46:34 +1000 Subject: [PATCH] NFS4: avoid underflow when converting error to pointer. In nfs4_create_sec_client, 'flavor' can hold a negative error code (returned from nfs4_negotiate_security), even though it is an 'enum' and hence unsigned. The code is careful to cast it to an (int) before testing if it is negative, however it doesn't cast to an (int) before calling ERR_PTR. On a machine where "void*" is larger than "int", this results in the unsigned equivalent of -1 (e.g. 0xffffffff) being converted to a pointer. Subsequent code determines that this is not negative, and so dereferences it with predictable results. So: cast 'flavor' to a (signed) int before passing to ERR_PTR. cc: Benny Halevy <bhalevy@tonian.com> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> --- fs/nfs/nfs4namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c index 398d5fd74157..4fdeb1b7042e 100644 --- a/fs/nfs/nfs4namespace.c +++ b/fs/nfs/nfs4namespace.c @@ -198,7 +198,7 @@ struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *clnt, struct inode *ino flavor = nfs4_negotiate_security(inode, name); if ((int)flavor < 0) - return ERR_PTR(flavor); + return ERR_PTR((int)flavor); clone = rpc_clone_client(clnt); if (IS_ERR(clone)) -- GitLab