[Qemu-devel] [PATCH] ppc405_uc: Fix buffer overflow

[Stefan Weil <sw@weilnetz.de>]

Report from smatch:

ppc405_uc.c:209 dcr_read_pob(12) error: buffer overflow 'pob->besr' 2 <= 2
ppc405_uc.c:232 dcr_write_pob(12) error: buffer overflow 'pob->besr' 2 <= 2

The old code reads and writes besr[POB0_BESR1 - POB0_BESR0] or besr[2]
which is one too much.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
---

As this code was wrong for more than 5 years, there is no urgent need to
fix it now for QEMU 1.2.

Regards,

Stefan Weil

 hw/ppc405_uc.c |   16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/hw/ppc405_uc.c b/hw/ppc405_uc.c
index 89e5013..b52ab2f 100644
--- a/hw/ppc405_uc.c
+++ b/hw/ppc405_uc.c
@@ -191,7 +191,8 @@ enum {
 typedef struct ppc4xx_pob_t ppc4xx_pob_t;
 struct ppc4xx_pob_t {
     uint32_t bear;
-    uint32_t besr[2];
+    uint32_t besr0;
+    uint32_t besr1;
 };
 
 static uint32_t dcr_read_pob (void *opaque, int dcrn)
@@ -205,8 +206,10 @@ static uint32_t dcr_read_pob (void *opaque, int dcrn)
         ret = pob->bear;
         break;
     case POB0_BESR0:
+        ret = pob->besr0;
+        break;
     case POB0_BESR1:
-        ret = pob->besr[dcrn - POB0_BESR0];
+        ret = pob->besr1;
         break;
     default:
         /* Avoid gcc warning */
@@ -227,9 +230,12 @@ static void dcr_write_pob (void *opaque, int dcrn, uint32_t val)
         /* Read only */
         break;
     case POB0_BESR0:
+        /* Write-clear */
+        pob->besr0 &= ~val;
+        break;
     case POB0_BESR1:
         /* Write-clear */
-        pob->besr[dcrn - POB0_BESR0] &= ~val;
+        pob->besr1 &= ~val;
         break;
     }
 }
@@ -241,8 +247,8 @@ static void ppc4xx_pob_reset (void *opaque)
     pob = opaque;
     /* No error */
     pob->bear = 0x00000000;
-    pob->besr[0] = 0x0000000;
-    pob->besr[1] = 0x0000000;
+    pob->besr0 = 0x0000000;
+    pob->besr1 = 0x0000000;
 }
 
 static void ppc4xx_pob_init(CPUPPCState *env)
-- 
1.7.10