From 57fbcd2b29aa74423d47a9efd783a1508ab1bfc5 Mon Sep 17 00:00:00 2001 From: Simon Tatham Date: Sat, 11 Dec 2021 11:13:00 +0000 Subject: malloc.c: check allocation sizes against PTRDIFF_MAX. I don't expect this to actually come up in any circumstance, but it prevents a warning in some versions of gcc that would otherwise arise from the use of 'int' to compute the input size: if gcc isn't confident that the int is positive, then it complains that possible inputs to malloc might be in the region of 2^64 - (small multiple of a negative 32-bit int). I would hope malloc would fail in any case on such an input, so failing a couple of lines earlier makes no important difference. Annoyingly, stdint.h is missing in my NestedVM build setup (though it has stdbool.h - it's not _totally_ C90). So I have to check that at cmake time. Also, removed the #defines for smalloc and friends from the tree234 test mode. These were needed in the old build system, when tree234-test was built ad-hoc without being linked against malloc.c. But now tree234-test links against the same utils library as everything else, and can use the real smalloc - and doing so prevents another of these warnings when compiling with -flto. --- malloc.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'malloc.c') diff --git a/malloc.c b/malloc.c index 7e5b87e..39bcfac 100644 --- a/malloc.c +++ b/malloc.c @@ -2,6 +2,9 @@ * malloc.c: safe wrappers around malloc, realloc, free, strdup */ +#ifndef NO_STDINT_H +#include +#endif #include #include #include "puzzles.h" @@ -12,6 +15,10 @@ */ void *smalloc(size_t size) { void *p; +#ifdef PTRDIFF_MAX + if (size > PTRDIFF_MAX) + fatal("allocation too large"); +#endif p = malloc(size); if (!p) fatal("out of memory"); @@ -32,6 +39,10 @@ void sfree(void *p) { */ void *srealloc(void *p, size_t size) { void *q; +#ifdef PTRDIFF_MAX + if (size > PTRDIFF_MAX) + fatal("allocation too large"); +#endif if (p) { q = realloc(p, size); } else { -- cgit v1.1