From 03c3359dfc490eaf922f88955d6a8cc51a37ce92 Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Thu, 4 Dec 2014 07:28:32 +0800 Subject: [PATCH] vmdk: Check descriptor file length when reading it Since a too small file cannot be a valid VMDK image, and also since the buffer's first 4 bytes will be unconditionally examined by vmdk_open_sparse, let's error out the small file case to be clear. Signed-off-by: Fam Zheng Reviewed-by: Max Reitz Reviewed-by: Markus Armbruster Reviewed-by: Don Koch Message-id: 1417649314-13704-5-git-send-email-famz@redhat.com Signed-off-by: Max Reitz Signed-off-by: Kevin Wolf --- block/vmdk.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/block/vmdk.c b/block/vmdk.c index 5f43226b35..b703395504 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -557,6 +557,14 @@ static char *vmdk_read_desc(BlockDriverState *file, uint64_t desc_offset, return NULL; } + if (size < 4) { + /* Both descriptor file and sparse image must be much larger than 4 + * bytes, also callers of vmdk_read_desc want to compare the first 4 + * bytes with VMDK4_MAGIC, let's error out if less is read. */ + error_setg(errp, "File is too small, not a valid image"); + return NULL; + } + size = MIN(size, (1 << 20) - 1); /* avoid unbounded allocation */ buf = g_malloc(size + 1);