From 7f7caec5c5a02df88ee941c1120aa4b0c8b2c1ab Mon Sep 17 00:00:00 2001
Message-Id: <7f7caec5c5a02df88ee941c1120aa4b0c8b2c1ab@dist-git>
From: John Ferlan <jferlan@redhat.com>
Date: Sat, 20 Aug 2016 09:11:45 -0400
Subject: [PATCH] qemu: Fix crash hot plugging luks volume

https://bugzilla.redhat.com/show_bug.cgi?id=1367259

Crash occurs because 'secrets' is being dereferenced in call:

        if (qemuDomainSecretSetup(conn, priv, secinfo, disk->info.alias,
                                  VIR_SECRET_USAGE_TYPE_VOLUME, NULL,
                                  &src->encryption->secrets[0]->seclookupdef,
                                  true) < 0)

(gdb) p *src->encryption
$1 = {format = 2, nsecrets = 0, secrets = 0x0, encinfo = {cipher_size = 0,
    cipher_name = 0x0, cipher_mode = 0x0, cipher_hash = 0x0, ivgen_name = 0x0,
    ivgen_hash = 0x0}}
(gdb) bt
    priv=priv@entry=0x7fffc03be160, disk=disk@entry=0x7fffb4002ae0)
    at qemu/qemu_domain.c:1087
    disk=0x7fffb4002ae0, vm=0x7fffc03a2580, driver=0x7fffc02ca390,
    conn=0x7fffb00009a0) at qemu/qemu_hotplug.c:355

Upon entry to qemuDomainAttachVirtioDiskDevice, src->encryption points
at a valid 'secret' buffer w/ nsecrets == 1; however, the call to
qemuDomainDetermineDiskChain will call virStorageFileGetMetadata
and eventually virStorageFileGetMetadataInternal where the src->encryption
was overwritten when probing the volume.

Commit id 'a48c7141' added code to virStorageFileGetMetadataInternal
to determine if the disk/volume would use/need encryption and allocated
a meta->encryption. This overwrote an existing encryption buffer
already provided by the XML

This patch adds a check for meta->encryption already present before
just allocating and overwriting an existing buffer. It then checks the
existing encryption data to ensure the XML provided format for the
disk matches the expected format read from the disk and errors if there
is a mismatch.

(cherry picked from commit b4478c16c02f28d88673709947124c6ea2fb4c7b)
Signed-off-by: John Ferlan <jferlan@redhat.com>
---
 src/util/virstoragefile.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c
index 471aa1f..feeb061 100644
--- a/src/util/virstoragefile.c
+++ b/src/util/virstoragefile.c
@@ -950,10 +950,21 @@ virStorageFileGetMetadataInternal(virStorageSourcePtr meta,
         for (i = 0; fileTypeInfo[meta->format].cryptInfo[i].format != 0; i++) {
             if (virStorageFileHasEncryptionFormat(&fileTypeInfo[meta->format].cryptInfo[i],
                                                   buf, len)) {
-                if (VIR_ALLOC(meta->encryption) < 0)
-                    goto cleanup;
+                int expt_fmt = fileTypeInfo[meta->format].cryptInfo[i].format;
+                if (!meta->encryption) {
+                    if (VIR_ALLOC(meta->encryption) < 0)
+                        goto cleanup;
 
-                meta->encryption->format = fileTypeInfo[meta->format].cryptInfo[i].format;
+                    meta->encryption->format = expt_fmt;
+                } else {
+                    if (meta->encryption->format != expt_fmt) {
+                        virReportError(VIR_ERR_XML_ERROR,
+                                       _("encryption format %d doesn't match "
+                                         "expected format %d"),
+                                       meta->encryption->format, expt_fmt);
+                        goto cleanup;
+                    }
+                }
             }
         }
     }
-- 
2.9.2