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
string-list.c
#include "cache.h"
#include "string-list.h"
void string_list_init(struct string_list *list, int strdup_strings)
{
memset(list, 0, sizeof(*list));
list->strdup_strings = strdup_strings;
}
/* if there is no exact match, point to the index where the entry could be
* inserted */
static int get_entry_index(const struct string_list *list, const char *string,
int *exact_match)
{
int left = -1, right = list->nr;
compare_strings_fn cmp = list->cmp ? list->cmp : strcmp;
while (left + 1 < right) {
int middle = left + (right - left) / 2;
int compare = cmp(string, list->items[middle].string);
if (compare < 0)
right = middle;
else if (compare > 0)
left = middle;
else {
*exact_match = 1;
return middle;
}
}
*exact_match = 0;
return right;
}
/* returns -1-index if already exists */
static int add_entry(int insert_at, struct string_list *list, const char *string)
{
int exact_match = 0;
int index = insert_at != -1 ? insert_at : get_entry_index(list, string, &exact_match);
if (exact_match)
return -1 - index;
ALLOC_GROW(list->items, list->nr+1, list->alloc);
if (index < list->nr)
MOVE_ARRAY(list->items + index + 1, list->items + index,
list->nr - index);
list->items[index].string = list->strdup_strings ?
xstrdup(string) : (char *)string;
list->items[index].util = NULL;
list->nr++;
return index;
}
struct string_list_item *string_list_insert(struct string_list *list, const char *string)
{
int index = add_entry(-1, list, string);
if (index < 0)
index = -1 - index;
return list->items + index;
}
void string_list_remove(struct string_list *list, const char *string,
int free_util)
{
int exact_match;
int i = get_entry_index(list, string, &exact_match);
if (exact_match) {
if (list->strdup_strings)
free(list->items[i].string);
if (free_util)
free(list->items[i].util);
list->nr--;
MOVE_ARRAY(list->items + i, list->items + i + 1, list->nr - i);
}
}
int string_list_has_string(const struct string_list *list, const char *string)
{
int exact_match;
get_entry_index(list, string, &exact_match);
return exact_match;
}
int string_list_find_insert_index(const struct string_list *list, const char *string,
int negative_existing_index)
{
int exact_match;
int index = get_entry_index(list, string, &exact_match);
if (exact_match)
index = -1 - (negative_existing_index ? index : 0);
return index;
}
struct string_list_item *string_list_lookup(struct string_list *list, const char *string)
{
int exact_match, i = get_entry_index(list, string, &exact_match);
if (!exact_match)
return NULL;
return list->items + i;
}
void string_list_remove_duplicates(struct string_list *list, int free_util)
{
if (list->nr > 1) {
int src, dst;
compare_strings_fn cmp = list->cmp ? list->cmp : strcmp;
for (src = dst = 1; src < list->nr; src++) {
if (!cmp(list->items[dst - 1].string, list->items[src].string)) {
if (list->strdup_strings)
free(list->items[src].string);
if (free_util)
free(list->items[src].util);
} else
list->items[dst++] = list->items[src];
}
list->nr = dst;
}
}
int for_each_string_list(struct string_list *list,
string_list_each_func_t fn, void *cb_data)
{
int i, ret = 0;
for (i = 0; i < list->nr; i++)
if ((ret = fn(&list->items[i], cb_data)))
break;
return ret;
}
void filter_string_list(struct string_list *list, int free_util,
string_list_each_func_t want, void *cb_data)
{
int src, dst = 0;
for (src = 0; src < list->nr; src++) {
if (want(&list->items[src], cb_data)) {
list->items[dst++] = list->items[src];
} else {
if (list->strdup_strings)
free(list->items[src].string);
if (free_util)
free(list->items[src].util);
}
}
list->nr = dst;
}
static int item_is_not_empty(struct string_list_item *item, void *unused)
{
return *item->string != '\0';
}
void string_list_remove_empty_items(struct string_list *list, int free_util)
{
filter_string_list(list, free_util, item_is_not_empty, NULL);
}
void string_list_clear(struct string_list *list, int free_util)
{
if (list->items) {
int i;
if (list->strdup_strings) {
for (i = 0; i < list->nr; i++)
free(list->items[i].string);
}
if (free_util) {
for (i = 0; i < list->nr; i++)
free(list->items[i].util);
}
free(list->items);
}
list->items = NULL;
list->nr = list->alloc = 0;
}
void string_list_clear_func(struct string_list *list, string_list_clear_func_t clearfunc)
{
if (list->items) {
int i;
if (clearfunc) {
for (i = 0; i < list->nr; i++)
clearfunc(list->items[i].util, list->items[i].string);
}
if (list->strdup_strings) {
for (i = 0; i < list->nr; i++)
free(list->items[i].string);
}
free(list->items);
}
list->items = NULL;
list->nr = list->alloc = 0;
}
struct string_list_item *string_list_append_nodup(struct string_list *list,
char *string)
{
struct string_list_item *retval;
ALLOC_GROW(list->items, list->nr + 1, list->alloc);
retval = &list->items[list->nr++];
retval->string = string;
retval->util = NULL;
return retval;
}
struct string_list_item *string_list_append(struct string_list *list,
const char *string)
{
return string_list_append_nodup(
list,
list->strdup_strings ? xstrdup(string) : (char *)string);
}
/*
* Encapsulate the compare function pointer because ISO C99 forbids
* casting from void * to a function pointer and vice versa.
*/
struct string_list_sort_ctx
{
compare_strings_fn cmp;
};
static int cmp_items(const void *a, const void *b, void *ctx)
{
struct string_list_sort_ctx *sort_ctx = ctx;
const struct string_list_item *one = a;
const struct string_list_item *two = b;
return sort_ctx->cmp(one->string, two->string);
}
void string_list_sort(struct string_list *list)
{
struct string_list_sort_ctx sort_ctx = {list->cmp ? list->cmp : strcmp};
QSORT_S(list->items, list->nr, cmp_items, &sort_ctx);
}
struct string_list_item *unsorted_string_list_lookup(struct string_list *list,
const char *string)
{
struct string_list_item *item;
compare_strings_fn cmp = list->cmp ? list->cmp : strcmp;
for_each_string_list_item(item, list)
if (!cmp(string, item->string))
return item;
return NULL;
}
int unsorted_string_list_has_string(struct string_list *list,
const char *string)
{
return unsorted_string_list_lookup(list, string) != NULL;
}
void unsorted_string_list_delete_item(struct string_list *list, int i, int free_util)
{
if (list->strdup_strings)
free(list->items[i].string);
if (free_util)
free(list->items[i].util);
list->items[i] = list->items[list->nr-1];
list->nr--;
}
int string_list_split(struct string_list *list, const char *string,
int delim, int maxsplit)
{
int count = 0;
const char *p = string, *end;
if (!list->strdup_strings)
die("internal error in string_list_split(): "
"list->strdup_strings must be set");
for (;;) {
count++;
if (maxsplit >= 0 && count > maxsplit) {
string_list_append(list, p);
return count;
}
end = strchr(p, delim);
if (end) {
string_list_append_nodup(list, xmemdupz(p, end - p));
p = end + 1;
} else {
string_list_append(list, p);
return count;
}
}
}
int string_list_split_in_place(struct string_list *list, char *string,
int delim, int maxsplit)
{
int count = 0;
char *p = string, *end;
if (list->strdup_strings)
die("internal error in string_list_split_in_place(): "
"list->strdup_strings must not be set");
for (;;) {
count++;
if (maxsplit >= 0 && count > maxsplit) {
string_list_append(list, p);
return count;
}
end = strchr(p, delim);
if (end) {
*end = '\0';
string_list_append(list, p);
p = end + 1;
} else {
string_list_append(list, p);
return count;
}
}
}
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