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[Qemu-devel] [PATCH 2/4] cg3: add extra check to prevent CG3 register ar
From: |
Mark Cave-Ayland |
Subject: |
[Qemu-devel] [PATCH 2/4] cg3: add extra check to prevent CG3 register array overflow |
Date: |
Sat, 24 May 2014 13:44:59 +0100 |
The case statements in the CG3 read and write register routines have a maximum
value of CG3_REG_SIZE, so if a value were written to this offset then it
would overflow the register array.
Currently this cannot be exploited since the MemoryRegion restricts accesses
to the range 0 ... CG3_REG_SIZE - 1, but it seems worth clarifying this for
future review and/or static analysis.
Signed-off-by: Mark Cave-Ayland <address@hidden>
CC: Paolo Bonzini <address@hidden>
---
hw/display/cg3.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/hw/display/cg3.c b/hw/display/cg3.c
index cd9297d..65ef7a7 100644
--- a/hw/display/cg3.c
+++ b/hw/display/cg3.c
@@ -177,7 +177,7 @@ static uint64_t cg3_reg_read(void *opaque, hwaddr addr,
unsigned size)
/* monitor ID 6, board type = 1 (color) */
val = s->regs[1] | CG3_SR_1152_900_76_B | CG3_SR_ID_COLOR;
break;
- case CG3_REG_FBC_CURSTART ... CG3_REG_SIZE:
+ case CG3_REG_FBC_CURSTART ... CG3_REG_SIZE - 1:
val = s->regs[addr - 0x10];
break;
default:
@@ -247,7 +247,7 @@ static void cg3_reg_write(void *opaque, hwaddr addr,
uint64_t val,
qemu_irq_lower(s->irq);
}
break;
- case CG3_REG_FBC_CURSTART ... CG3_REG_SIZE:
+ case CG3_REG_FBC_CURSTART ... CG3_REG_SIZE - 1:
s->regs[addr - 0x10] = val;
break;
default:
--
1.7.10.4