From ddbc22e27e672b6b180757ea1d7f8481dbb88128 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Wed, 10 Dec 2014 15:54:37 -0800 Subject: fs/hfs/catalog.c: fix comparison bug in hfs_cat_keycmp Relying on the sign (after casting to int) of the difference of two quantities for comparison is usually wrong. For example, should a-b turn out to be 2^31, the return value of cmp(a,b) is -2^31; but that would also be the return value from cmp(b, a). So a compares less than b and b compares less than a. One can also easily find three values a,b,c such that a compares less than b, b compares less than c, but a does not compare less than c. Signed-off-by: Rasmus Villemoes Reviewed-by: Vyacheslav Dubeyko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/hfs/catalog.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) (limited to 'fs') diff --git a/fs/hfs/catalog.c b/fs/hfs/catalog.c index ff0316b..db458ee 100644 --- a/fs/hfs/catalog.c +++ b/fs/hfs/catalog.c @@ -162,14 +162,16 @@ err2: */ int hfs_cat_keycmp(const btree_key *key1, const btree_key *key2) { - int retval; + __be32 k1p, k2p; - retval = be32_to_cpu(key1->cat.ParID) - be32_to_cpu(key2->cat.ParID); - if (!retval) - retval = hfs_strcmp(key1->cat.CName.name, key1->cat.CName.len, - key2->cat.CName.name, key2->cat.CName.len); + k1p = key1->cat.ParID; + k2p = key2->cat.ParID; - return retval; + if (k1p != k2p) + return be32_to_cpu(k1p) < be32_to_cpu(k2p) ? -1 : 1; + + return hfs_strcmp(key1->cat.CName.name, key1->cat.CName.len, + key2->cat.CName.name, key2->cat.CName.len); } /* Try to get a catalog entry for given catalog id */ -- cgit v1.1