Revision 447ac906e189535e77dcb1f4bbe3f1bc917d4c12 authored by Patrick Steinhardt on 01 December 2022, 14:45:31 UTC, committed by Junio C Hamano on 05 December 2022, 06:14:16 UTC
The `struct attr_stack` tracks the stack of all patterns together with their attributes. When parsing a gitattributes file that has more than 2^31 such patterns though we may trigger multiple out-of-bounds reads on 64 bit platforms. This is because while the `num_matches` variable is an unsigned integer, we always use a signed integer to iterate over them. I have not been able to reproduce this issue due to memory constraints on my systems. But despite the out-of-bounds reads, the worst thing that can seemingly happen is to call free(3P) with a garbage pointer when calling `attr_stack_free()`. Fix this bug by using unsigned integers to iterate over the array. While this makes the iteration somewhat awkward when iterating in reverse, it is at least better than knowingly running into an out-of-bounds read. While at it, convert the call to `ALLOC_GROW` to use `ALLOC_GROW_BY` instead. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 34ace8b
strmap.c
#include "git-compat-util.h"
#include "strmap.h"
#include "mem-pool.h"
int cmp_strmap_entry(const void *hashmap_cmp_fn_data,
const struct hashmap_entry *entry1,
const struct hashmap_entry *entry2,
const void *keydata)
{
const struct strmap_entry *e1, *e2;
e1 = container_of(entry1, const struct strmap_entry, ent);
e2 = container_of(entry2, const struct strmap_entry, ent);
return strcmp(e1->key, e2->key);
}
static struct strmap_entry *find_strmap_entry(struct strmap *map,
const char *str)
{
struct strmap_entry entry;
hashmap_entry_init(&entry.ent, strhash(str));
entry.key = str;
return hashmap_get_entry(&map->map, &entry, ent, NULL);
}
void strmap_init(struct strmap *map)
{
strmap_init_with_options(map, NULL, 1);
}
void strmap_init_with_options(struct strmap *map,
struct mem_pool *pool,
int strdup_strings)
{
hashmap_init(&map->map, cmp_strmap_entry, NULL, 0);
map->pool = pool;
map->strdup_strings = strdup_strings;
}
static void strmap_free_entries_(struct strmap *map, int free_values)
{
struct hashmap_iter iter;
struct strmap_entry *e;
if (!map)
return;
if (!free_values && map->pool)
/* Memory other than util is owned by and freed with the pool */
return;
/*
* We need to iterate over the hashmap entries and free
* e->key and e->value ourselves; hashmap has no API to
* take care of that for us. Since we're already iterating over
* the hashmap, though, might as well free e too and avoid the need
* to make some call into the hashmap API to do that.
*/
hashmap_for_each_entry(&map->map, &iter, e, ent) {
if (free_values)
free(e->value);
if (!map->pool)
free(e);
}
}
void strmap_clear(struct strmap *map, int free_values)
{
strmap_free_entries_(map, free_values);
hashmap_clear(&map->map);
}
void strmap_partial_clear(struct strmap *map, int free_values)
{
strmap_free_entries_(map, free_values);
hashmap_partial_clear(&map->map);
}
static struct strmap_entry *create_entry(struct strmap *map,
const char *str,
void *data)
{
struct strmap_entry *entry;
if (map->strdup_strings) {
if (!map->pool) {
FLEXPTR_ALLOC_STR(entry, key, str);
} else {
size_t len = st_add(strlen(str), 1); /* include NUL */
entry = mem_pool_alloc(map->pool,
st_add(sizeof(*entry), len));
memcpy(entry + 1, str, len);
entry->key = (void *)(entry + 1);
}
} else if (!map->pool) {
entry = xmalloc(sizeof(*entry));
} else {
entry = mem_pool_alloc(map->pool, sizeof(*entry));
}
hashmap_entry_init(&entry->ent, strhash(str));
if (!map->strdup_strings)
entry->key = str;
entry->value = data;
return entry;
}
void *strmap_put(struct strmap *map, const char *str, void *data)
{
struct strmap_entry *entry = find_strmap_entry(map, str);
if (entry) {
void *old = entry->value;
entry->value = data;
return old;
}
entry = create_entry(map, str, data);
hashmap_add(&map->map, &entry->ent);
return NULL;
}
struct strmap_entry *strmap_get_entry(struct strmap *map, const char *str)
{
return find_strmap_entry(map, str);
}
void *strmap_get(struct strmap *map, const char *str)
{
struct strmap_entry *entry = find_strmap_entry(map, str);
return entry ? entry->value : NULL;
}
int strmap_contains(struct strmap *map, const char *str)
{
return find_strmap_entry(map, str) != NULL;
}
void strmap_remove(struct strmap *map, const char *str, int free_value)
{
struct strmap_entry entry, *ret;
hashmap_entry_init(&entry.ent, strhash(str));
entry.key = str;
ret = hashmap_remove_entry(&map->map, &entry, ent, NULL);
if (!ret)
return;
if (free_value)
free(ret->value);
if (!map->pool)
free(ret);
}
void strintmap_incr(struct strintmap *map, const char *str, intptr_t amt)
{
struct strmap_entry *entry = find_strmap_entry(&map->map, str);
if (entry) {
intptr_t *whence = (intptr_t*)&entry->value;
*whence += amt;
}
else
strintmap_set(map, str, map->default_value + amt);
}
int strset_add(struct strset *set, const char *str)
{
/*
* Cannot use strmap_put() because it'll return NULL in both cases:
* - cannot find str: NULL means "not found"
* - does find str: NULL is the value associated with str
*/
struct strmap_entry *entry = find_strmap_entry(&set->map, str);
if (entry)
return 0;
entry = create_entry(&set->map, str, NULL);
hashmap_add(&set->map.map, &entry->ent);
return 1;
}
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