mirror of
https://github.com/Divested-Mobile/DivestOS-Build.git
synced 2024-12-30 01:46:30 -05:00
95 lines
2.8 KiB
Diff
95 lines
2.8 KiB
Diff
|
From 389b185cb2f17fff994dbdf8d4bac003d4b2b6b3 Mon Sep 17 00:00:00 2001
|
||
|
|
From: Jim Lin <jilin@nvidia.com>
|
||
|
|
Date: Fri, 13 Jan 2017 16:07:58 +0800
|
||
|
|
Subject: FROMLIST: CHROMIUM: usb: gadget: configfs: Fix KASAN use-after-free
|
||
|
|
|
||
|
|
When gadget is disconnected, running sequence is like this.
|
||
|
|
. android_work: sent uevent USB_STATE=DISCONNECTED
|
||
|
|
. Call trace:
|
||
|
|
usb_string_copy+0xd0/0x128
|
||
|
|
gadget_config_name_configuration_store+0x4
|
||
|
|
gadget_config_name_attr_store+0x40/0x50
|
||
|
|
configfs_write_file+0x198/0x1f4
|
||
|
|
vfs_write+0x100/0x220
|
||
|
|
SyS_write+0x58/0xa8
|
||
|
|
. configfs_composite_unbind
|
||
|
|
. configfs_composite_bind
|
||
|
|
|
||
|
|
In configfs_composite_bind, it has
|
||
|
|
"cn->strings.s = cn->configuration;"
|
||
|
|
|
||
|
|
When usb_string_copy is invoked. it would
|
||
|
|
allocate memory, copy input string, release previous pointed memory space,
|
||
|
|
and use new allocated memory.
|
||
|
|
|
||
|
|
When gadget is connected, host sends down request to get information.
|
||
|
|
Call trace:
|
||
|
|
usb_gadget_get_string+0xec/0x168
|
||
|
|
lookup_string+0x64/0x98
|
||
|
|
composite_setup+0xa34/0x1ee8
|
||
|
|
android_setup+0xb4/0x140
|
||
|
|
|
||
|
|
If gadget is disconnected and connected quickly, in the failed case,
|
||
|
|
cn->configuration memory has been released by usb_string_copy kfree but
|
||
|
|
configfs_composite_bind hasn't been run in time to assign new allocated
|
||
|
|
"cn->configuration" pointer to "cn->strings.s".
|
||
|
|
|
||
|
|
When "strlen(s->s) of usb_gadget_get_string is being executed, the dangling
|
||
|
|
memory is accessed, "BUG: KASAN: use-after-free" error occurs.
|
||
|
|
|
||
|
|
BUG=chrome-os-partner:58412
|
||
|
|
TEST=After smaug device was connected to ubuntu PC host, detached and attached
|
||
|
|
type-C cable quickly several times without seeing
|
||
|
|
"BUG: KASAN: use-after-free in usb_gadget_get_string".
|
||
|
|
|
||
|
|
Bug: 31614969
|
||
|
|
Change-Id: I58240ee7c55ae8f8fb8597d14f09c5ac07abb032
|
||
|
|
Signed-off-by: Jim Lin <jilin@nvidia.com>
|
||
|
|
Signed-off-by: Siqi Lin <siqilin@google.com>
|
||
|
|
(am from https://chromium-review.googlesource.com/#/c/428059/3)
|
||
|
|
---
|
||
|
|
drivers/usb/gadget/configfs.c | 17 ++++++++++++-----
|
||
|
|
1 file changed, 12 insertions(+), 5 deletions(-)
|
||
|
|
|
||
|
|
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
|
||
|
|
index c484d9a..f7d8a3d 100644
|
||
|
|
--- a/drivers/usb/gadget/configfs.c
|
||
|
|
+++ b/drivers/usb/gadget/configfs.c
|
||
|
|
@@ -130,21 +130,28 @@ struct gadget_config_name {
|
||
|
|
struct list_head list;
|
||
|
|
};
|
||
|
|
|
||
|
|
+#define MAX_USB_STRING_LEN 126
|
||
|
|
+#define MAX_USB_STRING_WITH_NULL_LEN (MAX_USB_STRING_LEN+1)
|
||
|
|
+
|
||
|
|
static int usb_string_copy(const char *s, char **s_copy)
|
||
|
|
{
|
||
|
|
int ret;
|
||
|
|
char *str;
|
||
|
|
char *copy = *s_copy;
|
||
|
|
ret = strlen(s);
|
||
|
|
- if (ret > 126)
|
||
|
|
+ if (ret > MAX_USB_STRING_LEN)
|
||
|
|
return -EOVERFLOW;
|
||
|
|
|
||
|
|
- str = kstrdup(s, GFP_KERNEL);
|
||
|
|
- if (!str)
|
||
|
|
- return -ENOMEM;
|
||
|
|
+ if (copy) {
|
||
|
|
+ str = copy;
|
||
|
|
+ } else {
|
||
|
|
+ str = kmalloc(MAX_USB_STRING_WITH_NULL_LEN, GFP_KERNEL);
|
||
|
|
+ if (!str)
|
||
|
|
+ return -ENOMEM;
|
||
|
|
+ }
|
||
|
|
+ strncpy(str, s, MAX_USB_STRING_WITH_NULL_LEN);
|
||
|
|
if (str[ret - 1] == '\n')
|
||
|
|
str[ret - 1] = '\0';
|
||
|
|
- kfree(copy);
|
||
|
|
*s_copy = str;
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
--
|
||
|
|
cgit v1.1
|
||
|
|
|