From b8f1b4c9b03d2ec06ed69d0f6769499d197eccd8 Mon Sep 17 00:00:00 2001

From: John Snow <jsnow@redhat.com>

Date: Tue, 24 Jul 2018 12:50:06 +0200

Subject: [PATCH 65/89] block: Fix parameter checking in

 bdrv_co_copy_range_internal

RH-Author: John Snow <jsnow@redhat.com>

Message-id: <20180718225511.14878-15-jsnow@redhat.com>

Patchwork-id: 81411

O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH 14/35] block: Fix parameter checking in bdrv_co_copy_range_internal

Bugzilla: 1207657

RH-Acked-by: Eric Blake <eblake@redhat.com>

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Fam Zheng <famz@redhat.com>

From: Fam Zheng <famz@redhat.com>

src may be NULL if BDRV_REQ_ZERO_WRITE flag is set, in this case only

check dst and dst->bs. This bug was introduced when moving in the

request tracking code from bdrv_co_copy_range, in 37aec7d75eb.

This especially fixes the possible segfault when initializing src_bs

with a NULL src.

Signed-off-by: Fam Zheng <famz@redhat.com>

Message-id: 20180703023758.14422-2-famz@redhat.com

Reviewed-by: Jeff Cody <jcody@redhat.com>

Signed-off-by: Jeff Cody <jcody@redhat.com>

(cherry picked from commit d4d3e5a0d53a57282955e8a3ed7acc1ca90552d9)

Signed-off-by: John Snow <jsnow@redhat.com>

---

 block/io.c | 28 +++++++++++++++-------------

 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/block/io.c b/block/io.c

index 136a5d0..7981239 100644

--- a/block/io.c

+++ b/block/io.c

@@ -2848,17 +2848,11 @@ static int coroutine_fn bdrv_co_copy_range_internal(BdrvChild *src,

                                                     bool recurse_src)

 {

     BdrvTrackedRequest src_req, dst_req;

-    BlockDriverState *src_bs = src->bs;

-    BlockDriverState *dst_bs = dst->bs;

     int ret;

-    if (!src || !dst || !src->bs || !dst->bs) {

+    if (!dst || !dst->bs) {

         return -ENOMEDIUM;

     }

-    ret = bdrv_check_byte_request(src->bs, src_offset, bytes);

-    if (ret) {

-        return ret;

-    }

     ret = bdrv_check_byte_request(dst->bs, dst_offset, bytes);

     if (ret) {

@@ -2868,17 +2862,25 @@ static int coroutine_fn bdrv_co_copy_range_internal(BdrvChild *src,

         return bdrv_co_pwrite_zeroes(dst, dst_offset, bytes, flags);

     }

+    if (!src || !src->bs) {

+        return -ENOMEDIUM;

+    }

+    ret = bdrv_check_byte_request(src->bs, src_offset, bytes);

+    if (ret) {

+        return ret;

+    }

+    

     if (!src->bs->drv->bdrv_co_copy_range_from

         || !dst->bs->drv->bdrv_co_copy_range_to

         || src->bs->encrypted || dst->bs->encrypted) {

         return -ENOTSUP;

     }

-    bdrv_inc_in_flight(src_bs);

-    bdrv_inc_in_flight(dst_bs);

-    tracked_request_begin(&src_req, src_bs, src_offset,

+    bdrv_inc_in_flight(src->bs);

+    bdrv_inc_in_flight(dst->bs);

+    tracked_request_begin(&src_req, src->bs, src_offset,

                           bytes, BDRV_TRACKED_READ);

-    tracked_request_begin(&dst_req, dst_bs, dst_offset,

+    tracked_request_begin(&dst_req, dst->bs, dst_offset,

                           bytes, BDRV_TRACKED_WRITE);

     wait_serialising_requests(&src_req);

@@ -2896,8 +2898,8 @@ static int coroutine_fn bdrv_co_copy_range_internal(BdrvChild *src,

     }

     tracked_request_end(&src_req);

     tracked_request_end(&dst_req);

-    bdrv_dec_in_flight(src_bs);

-    bdrv_dec_in_flight(dst_bs);

+    bdrv_dec_in_flight(src->bs);

+    bdrv_dec_in_flight(dst->bs);

     return ret;

 }

-- 

1.8.3.1