From 689898009c6930b8a9ce598e85678bfc0f131594 Mon Sep 17 00:00:00 2001
From: Markus Armbruster <armbru@redhat.com>
Date: Fri, 17 May 2019 06:50:51 +0200
Subject: [PATCH 24/53] block/pflash_cfi02: Fix memory leak and potential
 use-after-free
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RH-Author: Markus Armbruster <armbru@redhat.com>
Message-id: <20190517065120.12028-3-armbru@redhat.com>
Patchwork-id: 87984
O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH v3 02/31] block/pflash_cfi02: Fix memory leak and potential use-after-free
Bugzilla: 1624009
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

From: Stephen Checkoway <stephen.checkoway@oberlin.edu>

Don't dynamically allocate the pflash's timer. But do use timer_del in
an unrealize function to make sure that the timer can't fire after the
pflash_t has been freed.

Signed-off-by: Stephen Checkoway <stephen.checkoway@oberlin.edu>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Wei Yang <richardw.yang@linux.intel.com>
Message-Id: <20190219153727.62279-1-stephen.checkoway@oberlin.edu>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
(cherry picked from commit d80cf1eb2e87df3a9bfb226bcc7fb3a1aa858817)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/block/pflash_cfi02.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/hw/block/pflash_cfi02.c b/hw/block/pflash_cfi02.c
index 75d1ae1..cbc3d4d 100644
--- a/hw/block/pflash_cfi02.c
+++ b/hw/block/pflash_cfi02.c
@@ -84,7 +84,7 @@ struct pflash_t {
     uint16_t unlock_addr0;
     uint16_t unlock_addr1;
     uint8_t cfi_table[0x52];
-    QEMUTimer *timer;
+    QEMUTimer timer;
     /* The device replicates the flash memory across its memory space.  Emulate
      * that by having a container (.mem) filled with an array of aliases
      * (.mem_mappings) pointing to the flash memory (.orig_mem).
@@ -431,7 +431,7 @@ static void pflash_write (pflash_t *pfl, hwaddr offset,
             }
             pfl->status = 0x00;
             /* Let's wait 5 seconds before chip erase is done */
-            timer_mod(pfl->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
+            timer_mod(&pfl->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
                       (NANOSECONDS_PER_SECOND * 5));
             break;
         case 0x30:
@@ -446,7 +446,7 @@ static void pflash_write (pflash_t *pfl, hwaddr offset,
             }
             pfl->status = 0x00;
             /* Let's wait 1/2 second before sector erase is done */
-            timer_mod(pfl->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
+            timer_mod(&pfl->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
                       (NANOSECONDS_PER_SECOND / 2));
             break;
         default:
@@ -658,7 +658,7 @@ static void pflash_cfi02_realize(DeviceState *dev, Error **errp)
     pfl->rom_mode = 1;
     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &pfl->mem);
 
-    pfl->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, pflash_timer, pfl);
+    timer_init_ns(&pfl->timer, QEMU_CLOCK_VIRTUAL, pflash_timer, pfl);
     pfl->wcycle = 0;
     pfl->cmd = 0;
     pfl->status = 0;
@@ -757,11 +757,18 @@ static Property pflash_cfi02_properties[] = {
     DEFINE_PROP_END_OF_LIST(),
 };
 
+static void pflash_cfi02_unrealize(DeviceState *dev, Error **errp)
+{
+    pflash_t *pfl = CFI_PFLASH02(dev);
+    timer_del(&pfl->timer);
+}
+
 static void pflash_cfi02_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = pflash_cfi02_realize;
+    dc->unrealize = pflash_cfi02_unrealize;
     dc->props = pflash_cfi02_properties;
     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 }
-- 
1.8.3.1