From 3c6681dc2c610038f536ad483a501e35a1a7312c Mon Sep 17 00:00:00 2001 From: davidxu Date: Thu, 27 Feb 2014 02:36:09 +0000 Subject: MFC r262277: malloc_aligned() may not leave enough space for pointer to allocated memory, saving the pointer will overwrite bytes belongs to another memory block unexpectly, to fix the problem, use (allocated address + sizeof(void *)) as initial value, and slip to next aligned address, so maximum extra bytes is sizeof(void *) + align - 1. Tested by: Andre Albsmeier < mail at ma17 dot ata dot myota dot orgndre > MFC r262334: Increase alignment to size of pointer if the alignment is too small. Some modules do not align data at least to size of pointer, they uses a smaller alignment, but our pointer should be aligned to its native boundary, otherwise on some platforms, hardware alignment checking will cause bus error. --- libexec/rtld-elf/xmalloc.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) (limited to 'libexec') diff --git a/libexec/rtld-elf/xmalloc.c b/libexec/rtld-elf/xmalloc.c index 3b3408c..ed195df 100644 --- a/libexec/rtld-elf/xmalloc.c +++ b/libexec/rtld-elf/xmalloc.c @@ -72,14 +72,12 @@ void * malloc_aligned(size_t size, size_t align) { void *mem, *res; - uintptr_t x; - size_t asize, r; - r = round(sizeof(void *), align); - asize = round(size, align) + r; - mem = xmalloc(asize); - x = (uintptr_t)mem; - res = (void *)round(x, align); + if (align < sizeof(void *)) + align = sizeof(void *); + + mem = xmalloc(size + sizeof(void *) + align - 1); + res = (void *)round((uintptr_t)mem + sizeof(void *), align); *(void **)((uintptr_t)res - sizeof(void *)) = mem; return (res); } -- cgit v1.1