[PATCH 2/6] test-hashmap: check allocation computation for overflow
- From
Jeff King <peff@peff.net>
- Date
- Feb 14, 2018, 18:06 UTC
- Message-ID
- <20180214180634.GB9919@sigill.intra.peff.net>
- In-Reply-To
- <20180214180322.GA9190@sigill.intra.peff.net>
When we allocate the test_entry flex-struct, we have to add up all of the elements that go into the flex array. If these were to overflow a size_t, this would allocate a too-small buffer, which we would then overflow in our memcpy steps.
Since this is just a test-helper, it probably doesn't matter in practice, but we should model the correct technique by using the st_add() macros.
Unfortunately, we cannot use the FLEX_ALLOC() macros here, because we are stuffing two different buffers into a single flex array.
While we're here, let's also swap out "malloc" for our error-checking "xmalloc", and use the preferred "sizeof(*var)" instead of "sizeof(type)".
Signed-off-by: Jeff King <peff@peff.net> --- t/helper/test-hashmap.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/t/helper/test-hashmap.c b/t/helper/test-hashmap.c index b36886bf35..2100877c2b 100644 --- a/t/helper/test-hashmap.c +++ b/t/helper/test-hashmap.c @@ -32,8 +32,7 @@ static int test_entry_cmp(const void *cmp_data, static struct test_entry *alloc_test_entry(int hash, char *key, int klen, char *value, int vlen) { - struct test_entry *entry = malloc(sizeof(struct test_entry) + klen - + vlen + 2); + struct test_entry *entry = xmalloc(st_add4(sizeof(*entry), klen, vlen, 2)); hashmap_entry_init(entry, hash); memcpy(entry->key, key, klen + 1); memcpy(entry->key + klen + 1, value, vlen + 1);
-- 2.16.1.464.gc4bae515b7