Image files that make qemu-img info read several gigabytes into the unknown header extensions list are bad. Just fail opening the image if an extension claims to be large.
Signed-off-by: Kevin Wolf <kw...@redhat.com> --- block/qcow2.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index f68f0e1..077fe05 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -108,6 +108,11 @@ static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, #ifdef DEBUG_EXT printf("ext.magic = 0x%x\n", ext.magic); #endif + if (ext.len > 65536) { + error_report("Header extension larger than 64k - this looks wrong"); + return -ENOTSUP; + } + switch (ext.magic) { case QCOW2_EXT_MAGIC_END: return 0; -- 1.7.6.5