path: root/fs
diff options
authorRasmus Villemoes <linux@rasmusvillemoes.dk>2014-12-05 16:40:07 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-01-16 06:59:02 -0800
commit11e404024797de1db3cbc2479a2f7e89b2a14ad8 (patch)
tree669cf2c5a04be16e2a52d456ce644d7628660ea1 /fs
parent6a388a8350c86335b940dea0a3cc63bdbcc238ca (diff)
fs: nfsd: Fix signedness bug in compare_blob
commit ef17af2a817db97d42dd2ec0a425231748e23dbc upstream. Bugs similar to the one in acbbe6fbb240 (kcmp: fix standard comparison bug) are in rich supply. In this variant, the problem is that struct xdr_netobj::len has type unsigned int, so the expression o1->len - o2->len _also_ has type unsigned int; it has completely well-defined semantics, and the result is some non-negative integer, which is always representable in a long long. But this means that if the conditional triggers, we are guaranteed to return a positive value from compare_blob. In this case it could be fixed by - res = o1->len - o2->len; + res = (long long)o1->len - (long long)o2->len; but I'd rather eliminate the usually broken 'return a - b;' idiom. Reviewed-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
1 files changed, 7 insertions, 8 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 836307ae1f08..4a58afa99654 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1200,15 +1200,14 @@ static int copy_cred(struct svc_cred *target, struct svc_cred *source)
return 0;
-static long long
+static int
compare_blob(const struct xdr_netobj *o1, const struct xdr_netobj *o2)
- long long res;
- res = o1->len - o2->len;
- if (res)
- return res;
- return (long long)memcmp(o1->data, o2->data, o1->len);
+ if (o1->len < o2->len)
+ return -1;
+ if (o1->len > o2->len)
+ return 1;
+ return memcmp(o1->data, o2->data, o1->len);
static int same_name(const char *n1, const char *n2)
@@ -1365,7 +1364,7 @@ add_clp_to_name_tree(struct nfs4_client *new_clp, struct rb_root *root)
static struct nfs4_client *
find_clp_in_name_tree(struct xdr_netobj *name, struct rb_root *root)
- long long cmp;
+ int cmp;
struct rb_node *node = root->rb_node;
struct nfs4_client *clp;