LibguestFS upstream has issued the following patch:
[1] https://github.com/libguestfs/libguestfs/commit/fa6a76050d82894365dfe32916903ef7fee3ffcd
to correct a double-free flaw in the virt-inspector / other virt-* tools,
which could lead to denial of service if some of the tools were used by
3rd party applications for inspection of untrusted guest files / images:
[2] https://www.redhat.com/archives/libguestfs/2013-May/msg00079.html
[3] https://www.redhat.com/archives/libguestfs/2013-May/msg00080.html
inspect: Use CLEANUP_* macros in inspection code.
can cause a double-free along an error path when certain guest files
are empty where we expected those files to contain at least one line.
This causes virt-inspector to crash when run on these guests.
The following is a test case which demonstrates the crash.
`f20rawhidex64' is a Fedora guest, but with small adjustments to the
test you could use any Linux guest for this test.
$ qemu-img create -f qcow2 -b f20rawhidex64 /tmp/test.qcow2
Formatting '/tmp/test.qcow2', fmt=qcow2 size=21474836480 backing_file='f20rawhidex64' encryption=off cluster_size=65536 lazy_refcounts=off
$ guestfish -i -a /tmp/test.qcow2 -- rm /etc/redhat-release : touch /etc/redhat-release
$ virt-inspector /tmp/test.qcow2
*** glibc detected *** virt-inspector: double free or corruption (fasttop): 0x00007f18bc9925a0 ***
======= Backtrace: =========
/lib64/libc.so.6(+0x34ecc7ca8e)[0x7f18b8e64a8e]
/lib64/libguestfs.so.0(+0x3f91898078)[0x7f18ba13c078]
/lib64/libguestfs.so.0(+0x3f91899761)[0x7f18ba13d761]
/lib64/libguestfs.so.0(+0x3f91896d12)[0x7f18ba13ad12]
/lib64/libguestfs.so.0(+0x3f91894140)[0x7f18ba138140]
/lib64/libguestfs.so.0(guestfs_inspect_os+0x35)[0x7f18ba0bcc35]
virt-inspector(main+0x547)[0x7f18ba7c57d7]
/lib64/libc.so.6(__libc_start_main+0xf5)[0x7f18b8e09a05]
virt-inspector(+0x6665)[0x7f18ba7c7665]
This is a denial of service, but not likely to be exploitable.
