From f5eecfb16d182d3c37df06bf20e6843f126b33fe Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Fri, 21 Sep 2018 10:18:00 +0100 Subject: [PATCH 3/4] exec: check that alignment is a power of two RH-Author: David Hildenbrand Message-id: <20180921101800.27360-1-david@redhat.com> Patchwork-id: 82229 O-Subject: [RHEL-8.0 qemu-kvm PATCH] exec: check that alignment is a power of two Bugzilla: 1630746 RH-Acked-by: Dr. David Alan Gilbert RH-Acked-by: Pankaj Gupta RH-Acked-by: Igor Mammedov RH-Acked-by: Paolo Bonzini BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1630746 Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=18439951 Branch: rhel8/master-2.12.0 Upstream: 61362b71c105ccb151ca16897a7d56534423f390 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 (cherry picked from commit 61362b71c105ccb151ca16897a7d56534423f390) Signed-off-by: David Hildenbrand Signed-off-by: Danilo C. L. de Paula --- exec.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/exec.c b/exec.c index 02b1efe..22cc7ef 100644 --- a/exec.c +++ b/exec.c @@ -1646,6 +1646,10 @@ 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__) -- 1.8.3.1