From 07ee2ab4fd0147edb64ba88e55407dd9d6656175 Mon Sep 17 00:00:00 2001 From: David Edmondson Date: Thu, 25 Mar 2021 12:29:37 +0100 Subject: [PATCH] block/vdi: Don't assume that blocks are larger than VdiHeader Given that the block size is read from the header of the VDI file, a wide variety of sizes might be seen. Rather than re-using a block sized memory region when writing the VDI header, allocate an appropriately sized buffer. Signed-off-by: David Edmondson Signed-off-by: Paolo Bonzini Acked-by: Max Reitz Message-id: 20210325112941.365238-3-pbonzini@redhat.com Message-Id: <20210309144015.557477-3-david.edmondson@oracle.com> Acked-by: Max Reitz Signed-off-by: Paolo Bonzini Signed-off-by: Stefan Hajnoczi --- block/vdi.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/block/vdi.c b/block/vdi.c index 2a6dc26124..548f8a057b 100644 --- a/block/vdi.c +++ b/block/vdi.c @@ -696,18 +696,20 @@ nonallocating_write: if (block) { /* One or more new blocks were allocated. */ - VdiHeader *header = (VdiHeader *) block; + VdiHeader *header; uint8_t *base; uint64_t offset; uint32_t n_sectors; + g_free(block); + header = g_malloc(sizeof(*header)); + logout("now writing modified header\n"); assert(VDI_IS_ALLOCATED(bmap_first)); *header = s->header; vdi_header_to_le(header); - ret = bdrv_pwrite(bs->file, 0, block, sizeof(VdiHeader)); - g_free(block); - block = NULL; + ret = bdrv_pwrite(bs->file, 0, header, sizeof(*header)); + g_free(header); if (ret < 0) { return ret;