[Qemu-devel] [PATCH] i2c: pm_smbus: check smb_index before block transfer write

[P J P]

From: Prasad J Pandit <p...@fedoraproject.org>

While performing block transfer write in smb_ioport_writeb(),
'smb_index' is incremented and used to index smb_data[] array.
Check 'smb_index' value to avoid OOB access.

Reported-by: Michael Hanselmann <pub...@hansmi.ch>
Signed-off-by: Prasad J Pandit <p...@fedoraproject.org>
---
 hw/i2c/pm_smbus.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/hw/i2c/pm_smbus.c b/hw/i2c/pm_smbus.c
index 685a2378ed..03062740cc 100644
--- a/hw/i2c/pm_smbus.c
+++ b/hw/i2c/pm_smbus.c
@@ -240,6 +240,9 @@ static void smb_ioport_writeb(void *opaque, hwaddr addr, 
uint64_t val,
             uint8_t read = s->smb_addr & 0x01;
 
             s->smb_index++;
+            if (s->smb_index >= PM_SMBUS_MAX_MSG_SIZE) {
+                s->smb_index = 0;
+            }
             if (!read && s->smb_index == s->smb_data0) {
                 uint8_t prot = (s->smb_ctl >> 2) & 0x07;
                 uint8_t cmd = s->smb_cmd;
-- 
2.19.2