Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit ef17af2a authored by Rasmus Villemoes's avatar Rasmus Villemoes Committed by J. Bruce Fields
Browse files

fs: nfsd: Fix signedness bug in compare_blob 



Bugs similar to the one in acbbe6fb (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: default avatarJeff Layton <jlayton@primarydata.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 83a712e0

fs/nfsd/nfs4state.c

+7 −8
Original line number Original line Diff line number Diff line
@@ -1714,15 +1714,14 @@ static int copy_cred(struct svc_cred *target, struct svc_cred *source) 
	return 0;

	return 0;

}

}





static long long

static int

compare_blob(const struct xdr_netobj *o1, const struct xdr_netobj *o2)

compare_blob(const struct xdr_netobj *o1, const struct xdr_netobj *o2)

{

{

	long long res;

	if (o1->len < o2->len)



		return -1;

	res = o1->len - o2->len;

	if (o1->len > o2->len)

	if (res)

		return 1;

		return res;

	return memcmp(o1->data, o2->data, o1->len);

	return (long long)memcmp(o1->data, o2->data, o1->len);

}

}





static int same_name(const char *n1, const char *n2)

static int same_name(const char *n1, const char *n2)
@@ -1910,7 +1909,7 @@ add_clp_to_name_tree(struct nfs4_client *new_clp, struct rb_root *root) 
static struct nfs4_client *

static struct nfs4_client *

find_clp_in_name_tree(struct xdr_netobj *name, struct rb_root *root)

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 rb_node *node = root->rb_node;

	struct nfs4_client *clp;

	struct nfs4_client *clp;