From: Frank Lichtenheld Date: Fri, 12 Dec 2025 10:09:14 +0000 (+0100) Subject: buffer: Change limits for array_mult_safe X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2b8149a4fe0d73ea0bedf2e282188d55c8511c45;p=thirdparty%2Fopenvpn.git buffer: Change limits for array_mult_safe - Lower the limit to 1GB on 32bit systems. The limit of 4GB-1 makes no sense on systems that usually don't allow a single process to allocate anything near to this limit. - Increate the limit from 4GB-1 to 4GB on other systems. It makes no difference in protection but makes it much easier to use the limit in other contexts, e.g. if dividing it. Change-Id: I4f95edd7ce2098180aa620a231727217f333a12d Signed-off-by: Frank Lichtenheld Acked-by: Gert Doering Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1436 Message-Id: <20251212100920.7671-1-gert@greenie.muc.de> URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg35044.html Signed-off-by: Gert Doering --- diff --git a/src/openvpn/buffer.c b/src/openvpn/buffer.c index 293622f98..40baca6f2 100644 --- a/src/openvpn/buffer.c +++ b/src/openvpn/buffer.c @@ -39,7 +39,7 @@ size_t array_mult_safe(const size_t m1, const size_t m2, const size_t extra) { - const size_t limit = 0xFFFFFFFF; + const size_t limit = ALLOC_SIZE_MAX; unsigned long long res = (unsigned long long)m1 * (unsigned long long)m2 + (unsigned long long)extra; if (unlikely(m1 > limit) || unlikely(m2 > limit) || unlikely(extra > limit) diff --git a/src/openvpn/buffer.h b/src/openvpn/buffer.h index ab2a29dc9..1dbe0b2b0 100644 --- a/src/openvpn/buffer.h +++ b/src/openvpn/buffer.h @@ -1044,6 +1044,18 @@ gc_reset(struct gc_arena *a) * Allocate memory to hold a structure */ +/* When allocating arrays make sure we do not use a excessive amount + * of memory. + */ +#if UINTPTR_MAX <= UINT32_MAX +/* 1 GB on 32bit systems, they usually can only allocate 2 GB for the + * whole process. + */ +#define ALLOC_SIZE_MAX (1u << 30) +#else +#define ALLOC_SIZE_MAX ((size_t)1 << 32) /* 4 GB */ +#endif + #define ALLOC_OBJ(dptr, type) \ { \ check_malloc_return((dptr) = (type *)malloc(sizeof(type))); \