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hw/usb: Fix buffer overflow in do_token_setup

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Store calculated setup_len in a local variable, verify it, and only
write it to the struct (USBDevice->setup_len) in case it passed the
sanity checks.

This prevent other code (do_token_{in,out} functions specifically)
from working with invalid USBDevice->setup_len values and overruning
the USBDevice->setup_buf[] buffer.
Fixes: CVE-2020-14364
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This commit is contained in:
Jiajie Li 2020-08-19 17:17:48 +08:00 committed by lijiajie
parent c112ba0442
commit 0a067ff27f
1 changed files with 46 additions and 0 deletions
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46
hw-usb-core-fix-buffer-overflow.patch Normal file
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@ -0,0 +1,46 @@
hw-usb-core-fix-buffer-overflow
From 18ad0451f113ffc3a2ff59c059d189cca1e42842 Mon Sep 17 00:00:00 2001
From: root <root@localhost.localdomain>
Date: Wed, 19 Aug 2020 17:04:04 +0800
Subject: [PATCH] hw/usb/core.c fix buffer overflow
Store calculated setup_len in a local variable, verify it,
and only write it to the struct (USBDevice->setup_len) in case it passed the
sanity checks.
This prevents other code (do_token_{in,out} function specifically)
from working with invalid USBDevice->setup_len values and overruning
the USBDevice->setup_buf[] buffer.
Store
Fixes: CVE-2020-14364
Signed-off-by: Gred Hoffman <kraxel@redhat.com>
---
hw/usb/core.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/hw/usb/core.c b/hw/usb/core.c
index 5abd128b..12342f13 100644
--- a/hw/usb/core.c
+++ b/hw/usb/core.c
@@ -144,6 +144,8 @@ static void do_token_setup(USBDevice *s, USBPacket *p)
"usb_generic_handle_packet: ctrl buffer too small (%d > %zu)\n",
s->setup_len, sizeof(s->data_buf));
p->status = USB_RET_STALL;
+ s->setup_len = 0;
+ s->setup_state = SETUP_STATE_ACK;
return;
}
@@ -277,6 +279,8 @@ static void do_parameter(USBDevice *s, USBPacket *p)
"usb_generic_handle_packet: ctrl buffer too small (%d > %zu)\n",
s->setup_len, sizeof(s->data_buf));
p->status = USB_RET_STALL;
+ s->setup_len = 0;
+ s->setup_state = SETUP_STATE_ACK;
return;
}
--
2.23.0