File scsi-lsi53c895a-really-fix-use-after-fre.patch of Package qemu.26285

From: Mauro Matteo Cascella <mcascell@redhat.com>
Date: Mon, 11 Jul 2022 14:33:16 +0200
Subject: scsi/lsi53c895a: really fix use-after-free in lsi_do_msgout
 (CVE-2022-0216)

Git-commit: 4367a20cc442c56b05611b4224de9a61908f9eac
References: bsc#1198038, CVE-2022-0216

Set current_req to NULL, not current_req->req, to prevent reusing a free'd
buffer in case of repeated SCSI cancel requests.  Also apply the fix to
CLEAR QUEUE and BUS DEVICE RESET messages as well, since they also cancel
the request.

Thanks to Alexander Bulekov for providing a reproducer.

Fixes: CVE-2022-0216
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/972
Signed-off-by: Mauro Matteo Cascella <mcascell@redhat.com>
Tested-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20220711123316.421279-1-mcascell@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Dario Faggioli <dfaggioli@suse.com>
---
 hw/scsi/lsi53c895a.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c
index 8033cf05023de397e91a0a121449..fbe3fa3dd282177057473816b812 100644
--- a/hw/scsi/lsi53c895a.c
+++ b/hw/scsi/lsi53c895a.c
@@ -1031,7 +1031,7 @@ static void lsi_do_msgout(LSIState *s)
             trace_lsi_do_msgout_abort(current_tag);
             if (current_req && current_req->req) {
                 scsi_req_cancel(current_req->req);
-                current_req->req = NULL;
+                current_req = NULL;
             }
             lsi_disconnect(s);
             break;
@@ -1057,6 +1057,7 @@ static void lsi_do_msgout(LSIState *s)
             /* clear the current I/O process */
             if (s->current) {
                 scsi_req_cancel(s->current->req);
+                current_req = NULL;
             }
 
             /* As the current implemented devices scsi_disk and scsi_generic