File block-qcow2-simplify-qcow2_co_invalidate.patch of Package qemu.37352

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Date: Tue, 2 Feb 2021 15:49:54 +0300
Subject: block/qcow2: simplify qcow2_co_invalidate_cache() (bsc#1227322,
 CVE-2024-4467)

qcow2_do_open correctly sets errp on each failure path. So, we can
simplify code in qcow2_co_invalidate_cache() and drop explicit error
propagation.

Add ERRP_GUARD() as mandated by the documentation in
include/qapi/error.h so that error_prepend() is actually called even if
errp is &error_fatal.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Message-Id: <20210202124956.63146-13-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
(cherry picked from commit e6247c9c9f9e4d01b00036f017da53d130981727)
References: bsc#1227322
References: CVE-2024-4467
Signed-off-by: Dario Faggioli <dfaggioli@suse.com>
---
 block/qcow2.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index de4fd451a68e4ae214b3f4833276..193fe2332c1b53095b600899153d 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2720,11 +2720,11 @@ static void qcow2_close(BlockDriverState *bs)
 static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs,
                                                    Error **errp)
 {
+    ERRP_GUARD();
     BDRVQcow2State *s = bs->opaque;
     int flags = s->flags;
     QCryptoBlock *crypto = NULL;
     QDict *options;
-    Error *local_err = NULL;
     int ret;
 
     /*
@@ -2742,16 +2742,11 @@ static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs,
 
     flags &= ~BDRV_O_INACTIVE;
     qemu_co_mutex_lock(&s->lock);
-    ret = qcow2_do_open(bs, options, flags, &local_err);
+    ret = qcow2_do_open(bs, options, flags, errp);
     qemu_co_mutex_unlock(&s->lock);
     qobject_unref(options);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "Could not reopen qcow2 layer: ");
-        bs->drv = NULL;
-        return;
-    } else if (ret < 0) {
-        error_setg_errno(errp, -ret, "Could not reopen qcow2 layer");
+    if (ret < 0) {
+        error_prepend(errp, "Could not reopen qcow2 layer: ");
         bs->drv = NULL;
         return;
     }