From: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Date: Thu, 29 Jul 2021 12:33:27 +0000 (+0200)
Subject: hw/net/can: sja1000 fix buff2frame_bas and buff2frame_pel when dlc is out of std... 
X-Git-Tag: v6.0.1~26
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4d3cfb2f6bb6afa07d0a9629136ae71eb6ab0268;p=thirdparty%2Fqemu.git

hw/net/can: sja1000 fix buff2frame_bas and buff2frame_pel when dlc is out of std CAN 8 bytes

Problem reported by openEuler fuzz-sig group.

The buff2frame_bas function (hw\net\can\can_sja1000.c)
infoleak(qemu5.x~qemu6.x) or stack-overflow(qemu 4.x).

Reported-by: Qiang Ning <ningqiang1@huawei.com>
Cc: qemu-stable@nongnu.org
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Signed-off-by: Jason Wang <jasowang@redhat.com>
(cherry picked from commit 11744862f27b9ba6488a247d2fd6bb83d9bc3c8d)
Signed-off-by: Michael Roth <michael.roth@amd.com>
---

diff --git a/hw/net/can/can_sja1000.c b/hw/net/can/can_sja1000.c
index 42d2f99dfb1..34eea684ced 100644
--- a/hw/net/can/can_sja1000.c
+++ b/hw/net/can/can_sja1000.c
@@ -275,6 +275,10 @@ static void buff2frame_pel(const uint8_t *buff, qemu_can_frame *frame)
     }
     frame->can_dlc = buff[0] & 0x0f;
 
+    if (frame->can_dlc > 8) {
+        frame->can_dlc = 8;
+    }
+
     if (buff[0] & 0x80) { /* Extended */
         frame->can_id |= QEMU_CAN_EFF_FLAG;
         frame->can_id |= buff[1] << 21; /* ID.28~ID.21 */
@@ -311,6 +315,10 @@ static void buff2frame_bas(const uint8_t *buff, qemu_can_frame *frame)
     }
     frame->can_dlc = buff[1] & 0x0f;
 
+    if (frame->can_dlc > 8) {
+        frame->can_dlc = 8;
+    }
+
     for (i = 0; i < frame->can_dlc; i++) {
         frame->data[i] = buff[2 + i];
     }