From: Gao Xiang <hsiangkao@linux.alibaba.com>
Date: Fri, 31 May 2024 07:13:05 +0000 (+0800)
Subject: erofs-utils: lib: fix incorrect xattr sharing
X-Git-Tag: v1.8~64
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b2f6da8ac935f44b026b01977819582d9c5831fc;p=platform%2Fupstream%2Ferofs-utils.git

erofs-utils: lib: fix incorrect xattr sharing

There are off-by-one issues after refactoring, and the size of kvbuf
should be calculated by EROFS_XATTR_KVSIZE instead.

Fixes: 5df285cf405d ("erofs-utils: lib: refactor extended attribute name prefixes")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240531071305.1183728-1-hsiangkao@linux.alibaba.com
---

diff --git a/lib/xattr.c b/lib/xattr.c
index 427933f..0f6fbe2 100644
--- a/lib/xattr.c
+++ b/lib/xattr.c
@@ -166,14 +166,6 @@ static unsigned int BKDRHash(char *str, unsigned int len)
 	return hash;
 }
 
-static unsigned int xattr_item_hash(char *buf, unsigned int len[2],
-				    unsigned int hash[2])
-{
-	hash[0] = BKDRHash(buf, len[0]);	/* key */
-	hash[1] = BKDRHash(buf + len[0], len[1]);	/* value */
-	return hash[0] ^ hash[1];
-}
-
 static unsigned int put_xattritem(struct xattr_item *item)
 {
 	if (item->count > 1)
@@ -188,11 +180,13 @@ static struct xattr_item *get_xattritem(char *kvbuf, unsigned int len[2])
 	struct ea_type_node *tnode;
 	unsigned int hash[2], hkey;
 
-	hkey = xattr_item_hash(kvbuf, len, hash);
+	hash[0] = BKDRHash(kvbuf, len[0]);
+	hash[1] = BKDRHash(kvbuf + EROFS_XATTR_KSIZE(len), len[1]);
+	hkey = hash[0] ^ hash[1];
 	hash_for_each_possible(ea_hashtable, item, node, hkey) {
 		if (item->len[0] == len[0] && item->len[1] == len[1] &&
 		    item->hash[0] == hash[0] && item->hash[1] == hash[1] &&
-		    !memcmp(kvbuf, item->kvbuf, len[0] + len[1])) {
+		    !memcmp(kvbuf, item->kvbuf, EROFS_XATTR_KVSIZE(len))) {
 			free(kvbuf);
 			++item->count;
 			return item;