From: Liam Merwick Date: Mon, 5 Nov 2018 21:38:36 +0000 (+0000) Subject: block: Null pointer dereference in blk_root_get_parent_desc() X-Git-Tag: v3.1.0-rc1~4^2^2~3 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=602414d1232723d92836babe8d7014b57b93e4d9;p=thirdparty%2Fqemu.git block: Null pointer dereference in blk_root_get_parent_desc() The dev_id returned by the call to blk_get_attached_dev_id() in blk_root_get_parent_desc() can be NULL (an internal call to object_get_canonical_path may have returned NULL). Instead of just checking this case before before dereferencing, adjust blk_get_attached_dev_id() to return the empty string if no object path can be found (similar to the case when blk->dev is NULL and an empty string is returned). Signed-off-by: Liam Merwick Message-id: 1541453919-25973-3-git-send-email-Liam.Merwick@oracle.com Reviewed-by: Max Reitz Signed-off-by: Max Reitz --- diff --git a/block/block-backend.c b/block/block-backend.c index 2a8f3b55f85..60d37a0c3d4 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -918,7 +918,8 @@ char *blk_get_attached_dev_id(BlockBackend *blk) } else if (dev->id) { return g_strdup(dev->id); } - return object_get_canonical_path(OBJECT(dev)); + + return object_get_canonical_path(OBJECT(dev)) ?: g_strdup(""); } /*