From a7932050f65844fb1f1145fee87c72aadaf4f995 Mon Sep 17 00:00:00 2001 From: Tavian Barnes Date: Thu, 11 May 2023 13:08:43 -0400 Subject: config: Saturate on overflow in flex_sizeof() --- src/config.h | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'src/config.h') diff --git a/src/config.h b/src/config.h index c6dcc1e..b2c58be 100644 --- a/src/config.h +++ b/src/config.h @@ -162,7 +162,17 @@ static inline size_t align_ceil(size_t align, size_t size) { flex_sizeof_impl(alignof(type), sizeof(type), offsetof(type, member), sizeof(((type *)NULL)->member[0]), count) static inline size_t flex_sizeof_impl(size_t align, size_t min, size_t offset, size_t size, size_t count) { - size_t ret = align_ceil(align, offset + size * count); + size_t ret = size * count; + size_t overflow = ret / size != count; + + ret += offset; + overflow |= ret < offset; + + size_t mask = align - 1; + ret += mask; + overflow |= ret < mask; + ret &= ~mask; + ret |= -overflow; // Make sure flex_sizeof(type, member, 0) >= sizeof(type), even if the // type has more padding than necessary for alignment -- cgit v1.2.3