From 61362b71c105ccb151ca16897a7d56534423f390 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 7 Jun 2018 17:47:05 +0200 Subject: [PATCH] exec: check that alignment is a power of two Right now we can crash QEMU using e.g. qemu-system-x86_64 -m 256M,maxmem=20G,slots=2 \ -object memory-backend-file,id=mem0,size=12288,mem-path=/dev/zero,align=12288 \ -device pc-dimm,id=dimm1,memdev=mem0 qemu-system-x86_64: util/mmap-alloc.c:115: qemu_ram_mmap: Assertion `is_power_of_2(align)' failed Fix this by adding a proper check. Signed-off-by: David Hildenbrand Message-Id: <20180607154705.6316-3-david@redhat.com> Reviewed-by: Michael S. Tsirkin Reviewed-by: Igor Mammedov Signed-off-by: Paolo Bonzini --- exec.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/exec.c b/exec.c index 610d0c0746..cdcf769daa 100644 --- a/exec.c +++ b/exec.c @@ -1841,6 +1841,10 @@ static void *file_ram_alloc(RAMBlock *block, " must be multiples of page size 0x%zx", block->mr->align, block->page_size); return NULL; + } else if (block->mr->align && !is_power_of_2(block->mr->align)) { + error_setg(errp, "alignment 0x%" PRIx64 + " must be a power of two", block->mr->align); + return NULL; } block->mr->align = MAX(block->page_size, block->mr->align); #if defined(__s390x__)