git__*allocarray: safer realloc and malloc

Introduce git__reallocarray that checks the product of the number
of elements and element size for overflow before allocation.  Also
introduce git__mallocarray that behaves like calloc, but without the
`c`.  (It does not zero memory, for those truly worried about every
cycle.)

1 files changed, 1 insertions, 6 deletions

diff --git a/src/vector.c b/src/vector.c
index b636032b1..27eafebc8 100644
--- a/src/vector.c
+++ b/src/vector.c
@@ -29,14 +29,9 @@ GIT_INLINE(size_t) compute_new_size(git_vector *v)
 
 GIT_INLINE(int) resize_vector(git_vector *v, size_t new_size)
 {
-	size_t new_bytes;
 	void *new_contents;
 
-	/* Check for overflow */
-	GITERR_CHECK_ALLOC_MULTIPLY(new_size, sizeof(void *));
-	new_bytes = new_size * sizeof(void *);
-
-	new_contents = git__realloc(v->contents, new_bytes);
+	new_contents = git__reallocarray(v->contents, new_size, sizeof(void *));
 	GITERR_CHECK_ALLOC(new_contents);
 
 	v->_alloc_size = new_size;