From 8bf9763656c9209f74cda460225da5a9939494cc Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Wed, 21 Sep 2016 14:56:04 +0200 Subject: [PATCH] sd-hwdb: fix child/value offset calculation It is not legal to use hard-coded types to calculate offsets. We must always use the offsets of the hwdb header to calculate those. Otherwise, we will break horribly if run on hwdb files written by other implementations or written with future extensions. Signed-off-by: David Herrmann --- src/libsystemd/sd-hwdb/sd-hwdb.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/src/libsystemd/sd-hwdb/sd-hwdb.c b/src/libsystemd/sd-hwdb/sd-hwdb.c index 062fa97b177..fb9522959f4 100644 --- a/src/libsystemd/sd-hwdb/sd-hwdb.c +++ b/src/libsystemd/sd-hwdb/sd-hwdb.c @@ -97,15 +97,20 @@ static void linebuf_rem_char(struct linebuf *buf) { linebuf_rem(buf, 1); } -static const struct trie_child_entry_f *trie_node_children(sd_hwdb *hwdb, const struct trie_node_f *node) { - return (const struct trie_child_entry_f *)((const char *)node + le64toh(hwdb->head->node_size)); +static const struct trie_child_entry_f *trie_node_child(sd_hwdb *hwdb, const struct trie_node_f *node, size_t idx) { + const char *base = (const char *)node; + + base += le64toh(hwdb->head->node_size); + base += idx * le64toh(hwdb->head->child_entry_size); + return (const struct trie_child_entry_f *)base; } -static const struct trie_value_entry_f *trie_node_values(sd_hwdb *hwdb, const struct trie_node_f *node) { +static const struct trie_value_entry_f *trie_node_value(sd_hwdb *hwdb, const struct trie_node_f *node, size_t idx) { const char *base = (const char *)node; base += le64toh(hwdb->head->node_size); base += node->children_count * le64toh(hwdb->head->child_entry_size); + base += idx * le64toh(hwdb->head->value_entry_size); return (const struct trie_value_entry_f *)base; } @@ -129,7 +134,7 @@ static const struct trie_node_f *node_lookup_f(sd_hwdb *hwdb, const struct trie_ struct trie_child_entry_f search; search.c = c; - child = bsearch(&search, trie_node_children(hwdb, node), node->children_count, + child = bsearch(&search, (const char *)node + le64toh(hwdb->head->node_size), node->children_count, le64toh(hwdb->head->child_entry_size), trie_children_cmp_f); if (child) return trie_node_from_off(hwdb, child->child_off); @@ -177,7 +182,7 @@ static int trie_fnmatch_f(sd_hwdb *hwdb, const struct trie_node_f *node, size_t linebuf_add(buf, prefix + p, len); for (i = 0; i < node->children_count; i++) { - const struct trie_child_entry_f *child = &trie_node_children(hwdb, node)[i]; + const struct trie_child_entry_f *child = trie_node_child(hwdb, node, i); linebuf_add_char(buf, child->c); err = trie_fnmatch_f(hwdb, trie_node_from_off(hwdb, child->child_off), 0, buf, search); @@ -188,8 +193,8 @@ static int trie_fnmatch_f(sd_hwdb *hwdb, const struct trie_node_f *node, size_t if (le64toh(node->values_count) && fnmatch(linebuf_get(buf), search, 0) == 0) for (i = 0; i < le64toh(node->values_count); i++) { - err = hwdb_add_property(hwdb, trie_string(hwdb, trie_node_values(hwdb, node)[i].key_off), - trie_string(hwdb, trie_node_values(hwdb, node)[i].value_off)); + err = hwdb_add_property(hwdb, trie_string(hwdb, trie_node_value(hwdb, node, i)->key_off), + trie_string(hwdb, trie_node_value(hwdb, node, i)->value_off)); if (err < 0) return err; } @@ -254,8 +259,8 @@ static int trie_search_f(sd_hwdb *hwdb, const char *search) { size_t n; for (n = 0; n < le64toh(node->values_count); n++) { - err = hwdb_add_property(hwdb, trie_string(hwdb, trie_node_values(hwdb, node)[n].key_off), - trie_string(hwdb, trie_node_values(hwdb, node)[n].value_off)); + err = hwdb_add_property(hwdb, trie_string(hwdb, trie_node_value(hwdb, node, n)->key_off), + trie_string(hwdb, trie_node_value(hwdb, node, n)->value_off)); if (err < 0) return err; } -- 2.39.2