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 427933fa4ae3ac62de3c0c68595c11f590761675..0f6fbe2303868949205aa0e5558e5004828640ab 100644 (file)
--- 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;