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Merge pull request #509 from JL2210/zero-alloc-use-fix-3

Fix use of zero-allocated memory

--- a/src/link/patch.c

+++ b/src/link/patch.c

@@ -82,10 +82,20 @@

 static void pushRPN(int32_t value)

 {

 	if (stack.size >= stack.capacity) {

-		stack.capacity *= 2;

+		static const size_t increase_factor = 2;

+

+		if (stack.capacity > SIZE_MAX / increase_factor)

+			errx(1, "Overflow in RPN stack resize");

+

+		stack.capacity *= increase_factor;

 		stack.buf =

 			realloc(stack.buf, sizeof(*stack.buf) * stack.capacity);

-		if (!stack.buf)

+		/*

+		 * Static analysis tools complain that the capacity might become

+		 * zero due to overflow, but fail to realize that it's caught by

+		 * the overflow check above. Hence the stringent check below.

+		 */

+		if (!stack.buf || !stack.capacity)

 			err(1, "Failed to resize RPN stack");

 	}