From: Frej Drejhammar <frej.drejhammar@gmail.com>
Date: Sun, 17 May 2015 14:34:49 +0000 (+0200)
Subject: Avoid buffer overrun on smaller AVRs
X-Git-Tag: v1.3~47^2
X-Git-Url: https://git.htl-mechatronik.at/public/?a=commitdiff_plain;h=f4a289091ee226cb9a323e2b2796ba706c2fc149;p=sx%2Fsimavr.git

Avoid buffer overrun on smaller AVRs

On smaller AVRs, such as the attiny13, MAX_IOs will be larger than the
size of SRAM which will lead to out of range writes to a malloc
allocated buffer. Therefore limit the number of bytes cleared to the
size of SRAM.
---

diff --git a/simavr/sim/sim_avr.c b/simavr/sim/sim_avr.c
index 6c985cc..3e12c74 100644
--- a/simavr/sim/sim_avr.c
+++ b/simavr/sim/sim_avr.c
@@ -118,10 +118,11 @@ void avr_terminate(avr_t * avr)
 
 void avr_reset(avr_t * avr)
 {
+	int noof_ios = MAX_IOs > avr->ramend ? avr->ramend : avr->ramend;
 	AVR_LOG(avr, LOG_TRACE, "%s reset\n", avr->mmcu);
 
 	avr->state = cpu_Running;
-	for(int i = 0x20; i <= MAX_IOs; i++)
+	for(int i = 0x20; i < noof_ios; i++)
 		avr->data[i] = 0;
 	_avr_sp_set(avr, avr->ramend);
 	avr->pc = 0;