Revision 513dc792d6060d5ef572e43852683097a8420f56 authored by Zhang Xiaoxu on 04 March 2020, 02:24:29 UTC, committed by Daniel Vetter on 06 March 2020, 20:06:34 UTC
When syzkaller tests, there is a UAF: BUG: KASan: use after free in vgacon_invert_region+0x9d/0x110 at addr ffff880000100000 Read of size 2 by task syz-executor.1/16489 page:ffffea0000004000 count:0 mapcount:-127 mapping: (null) index:0x0 page flags: 0xfffff00000000() page dumped because: kasan: bad access detected CPU: 1 PID: 16489 Comm: syz-executor.1 Not tainted Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014 Call Trace: [<ffffffffb119f309>] dump_stack+0x1e/0x20 [<ffffffffb04af957>] kasan_report+0x577/0x950 [<ffffffffb04ae652>] __asan_load2+0x62/0x80 [<ffffffffb090f26d>] vgacon_invert_region+0x9d/0x110 [<ffffffffb0a39d95>] invert_screen+0xe5/0x470 [<ffffffffb0a21dcb>] set_selection+0x44b/0x12f0 [<ffffffffb0a3bfae>] tioclinux+0xee/0x490 [<ffffffffb0a1d114>] vt_ioctl+0xff4/0x2670 [<ffffffffb0a0089a>] tty_ioctl+0x46a/0x1a10 [<ffffffffb052db3d>] do_vfs_ioctl+0x5bd/0xc40 [<ffffffffb052e2f2>] SyS_ioctl+0x132/0x170 [<ffffffffb11c9b1b>] system_call_fastpath+0x22/0x27 Memory state around the buggy address: ffff8800000fff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8800000fff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff880000100000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff It can be reproduce in the linux mainline by the program: #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/ioctl.h> #include <linux/vt.h> struct tiocl_selection { unsigned short xs; /* X start */ unsigned short ys; /* Y start */ unsigned short xe; /* X end */ unsigned short ye; /* Y end */ unsigned short sel_mode; /* selection mode */ }; #define TIOCL_SETSEL 2 struct tiocl { unsigned char type; unsigned char pad; struct tiocl_selection sel; }; int main() { int fd = 0; const char *dev = "/dev/char/4:1"; struct vt_consize v = {0}; struct tiocl tioc = {0}; fd = open(dev, O_RDWR, 0); v.v_rows = 3346; ioctl(fd, VT_RESIZEX, &v); tioc.type = TIOCL_SETSEL; ioctl(fd, TIOCLINUX, &tioc); return 0; } When resize the screen, update the 'vc->vc_size_row' to the new_row_size, but when 'set_origin' in 'vgacon_set_origin', vgacon use 'vga_vram_base' for 'vc_origin' and 'vc_visible_origin', not 'vc_screenbuf'. It maybe smaller than 'vc_screenbuf'. When TIOCLINUX, use the new_row_size to calc the offset, it maybe larger than the vga_vram_size in vgacon driver, then bad access. Also, if set an larger screenbuf firstly, then set an more larger screenbuf, when copy old_origin to new_origin, a bad access may happen. So, If the screen size larger than vga_vram, resize screen should be failed. This alse fix CVE-2020-8649 and CVE-2020-8647. Linus pointed out that overflow checking seems absent. We're saved by the existing bounds checks in vc_do_resize() with rather strict limits: if (cols > VC_RESIZE_MAXCOL || lines > VC_RESIZE_MAXROW) return -EINVAL; Fixes: 0aec4867dca14 ("[PATCH] SVGATextMode fix") Reference: CVE-2020-8647 and CVE-2020-8649 Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com> [danvet: augment commit message to point out overflow safety] Cc: stable@vger.kernel.org Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20200304022429.37738-1-zhangxiaoxu5@huawei.com
1 parent 2ac4853
rtc-max8925.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* RTC driver for Maxim MAX8925
*
* Copyright (C) 2009-2010 Marvell International Ltd.
* Haojian Zhuang <haojian.zhuang@marvell.com>
*/
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/mfd/max8925.h>
enum {
RTC_SEC = 0,
RTC_MIN,
RTC_HOUR,
RTC_WEEKDAY,
RTC_DATE,
RTC_MONTH,
RTC_YEAR1,
RTC_YEAR2,
};
#define MAX8925_RTC_SEC 0x00
#define MAX8925_RTC_MIN 0x01
#define MAX8925_RTC_HOUR 0x02
#define MAX8925_RTC_WEEKDAY 0x03
#define MAX8925_RTC_DATE 0x04
#define MAX8925_RTC_MONTH 0x05
#define MAX8925_RTC_YEAR1 0x06
#define MAX8925_RTC_YEAR2 0x07
#define MAX8925_ALARM0_SEC 0x08
#define MAX8925_ALARM0_MIN 0x09
#define MAX8925_ALARM0_HOUR 0x0a
#define MAX8925_ALARM0_WEEKDAY 0x0b
#define MAX8925_ALARM0_DATE 0x0c
#define MAX8925_ALARM0_MON 0x0d
#define MAX8925_ALARM0_YEAR1 0x0e
#define MAX8925_ALARM0_YEAR2 0x0f
#define MAX8925_ALARM1_SEC 0x10
#define MAX8925_ALARM1_MIN 0x11
#define MAX8925_ALARM1_HOUR 0x12
#define MAX8925_ALARM1_WEEKDAY 0x13
#define MAX8925_ALARM1_DATE 0x14
#define MAX8925_ALARM1_MON 0x15
#define MAX8925_ALARM1_YEAR1 0x16
#define MAX8925_ALARM1_YEAR2 0x17
#define MAX8925_RTC_CNTL 0x1b
#define MAX8925_RTC_STATUS 0x20
#define TIME_NUM 8
#define ALARM_1SEC (1 << 7)
#define HOUR_12 (1 << 7)
#define HOUR_AM_PM (1 << 5)
#define ALARM0_IRQ (1 << 3)
#define ALARM1_IRQ (1 << 2)
#define ALARM0_STATUS (1 << 2)
#define ALARM1_STATUS (1 << 1)
struct max8925_rtc_info {
struct rtc_device *rtc_dev;
struct max8925_chip *chip;
struct i2c_client *rtc;
struct device *dev;
int irq;
};
static irqreturn_t rtc_update_handler(int irq, void *data)
{
struct max8925_rtc_info *info = (struct max8925_rtc_info *)data;
/* disable ALARM0 except for 1SEC alarm */
max8925_set_bits(info->rtc, MAX8925_ALARM0_CNTL, 0x7f, 0);
rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static int tm_calc(struct rtc_time *tm, unsigned char *buf, int len)
{
if (len < TIME_NUM)
return -EINVAL;
tm->tm_year = (buf[RTC_YEAR2] >> 4) * 1000
+ (buf[RTC_YEAR2] & 0xf) * 100
+ (buf[RTC_YEAR1] >> 4) * 10
+ (buf[RTC_YEAR1] & 0xf);
tm->tm_year -= 1900;
tm->tm_mon = ((buf[RTC_MONTH] >> 4) & 0x01) * 10
+ (buf[RTC_MONTH] & 0x0f);
tm->tm_mday = ((buf[RTC_DATE] >> 4) & 0x03) * 10
+ (buf[RTC_DATE] & 0x0f);
tm->tm_wday = buf[RTC_WEEKDAY] & 0x07;
if (buf[RTC_HOUR] & HOUR_12) {
tm->tm_hour = ((buf[RTC_HOUR] >> 4) & 0x1) * 10
+ (buf[RTC_HOUR] & 0x0f);
if (buf[RTC_HOUR] & HOUR_AM_PM)
tm->tm_hour += 12;
} else
tm->tm_hour = ((buf[RTC_HOUR] >> 4) & 0x03) * 10
+ (buf[RTC_HOUR] & 0x0f);
tm->tm_min = ((buf[RTC_MIN] >> 4) & 0x7) * 10
+ (buf[RTC_MIN] & 0x0f);
tm->tm_sec = ((buf[RTC_SEC] >> 4) & 0x7) * 10
+ (buf[RTC_SEC] & 0x0f);
return 0;
}
static int data_calc(unsigned char *buf, struct rtc_time *tm, int len)
{
unsigned char high, low;
if (len < TIME_NUM)
return -EINVAL;
high = (tm->tm_year + 1900) / 1000;
low = (tm->tm_year + 1900) / 100;
low = low - high * 10;
buf[RTC_YEAR2] = (high << 4) + low;
high = (tm->tm_year + 1900) / 10;
low = tm->tm_year + 1900;
low = low - high * 10;
high = high - (high / 10) * 10;
buf[RTC_YEAR1] = (high << 4) + low;
high = tm->tm_mon / 10;
low = tm->tm_mon;
low = low - high * 10;
buf[RTC_MONTH] = (high << 4) + low;
high = tm->tm_mday / 10;
low = tm->tm_mday;
low = low - high * 10;
buf[RTC_DATE] = (high << 4) + low;
buf[RTC_WEEKDAY] = tm->tm_wday;
high = tm->tm_hour / 10;
low = tm->tm_hour;
low = low - high * 10;
buf[RTC_HOUR] = (high << 4) + low;
high = tm->tm_min / 10;
low = tm->tm_min;
low = low - high * 10;
buf[RTC_MIN] = (high << 4) + low;
high = tm->tm_sec / 10;
low = tm->tm_sec;
low = low - high * 10;
buf[RTC_SEC] = (high << 4) + low;
return 0;
}
static int max8925_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct max8925_rtc_info *info = dev_get_drvdata(dev);
unsigned char buf[TIME_NUM];
int ret;
ret = max8925_bulk_read(info->rtc, MAX8925_RTC_SEC, TIME_NUM, buf);
if (ret < 0)
goto out;
ret = tm_calc(tm, buf, TIME_NUM);
out:
return ret;
}
static int max8925_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct max8925_rtc_info *info = dev_get_drvdata(dev);
unsigned char buf[TIME_NUM];
int ret;
ret = data_calc(buf, tm, TIME_NUM);
if (ret < 0)
goto out;
ret = max8925_bulk_write(info->rtc, MAX8925_RTC_SEC, TIME_NUM, buf);
out:
return ret;
}
static int max8925_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct max8925_rtc_info *info = dev_get_drvdata(dev);
unsigned char buf[TIME_NUM];
int ret;
ret = max8925_bulk_read(info->rtc, MAX8925_ALARM0_SEC, TIME_NUM, buf);
if (ret < 0)
goto out;
ret = tm_calc(&alrm->time, buf, TIME_NUM);
if (ret < 0)
goto out;
ret = max8925_reg_read(info->rtc, MAX8925_RTC_IRQ_MASK);
if (ret < 0)
goto out;
if (ret & ALARM0_IRQ) {
alrm->enabled = 0;
} else {
ret = max8925_reg_read(info->rtc, MAX8925_ALARM0_CNTL);
if (ret < 0)
goto out;
if (!ret)
alrm->enabled = 0;
else
alrm->enabled = 1;
}
ret = max8925_reg_read(info->rtc, MAX8925_RTC_STATUS);
if (ret < 0)
goto out;
if (ret & ALARM0_STATUS)
alrm->pending = 1;
else
alrm->pending = 0;
return 0;
out:
return ret;
}
static int max8925_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct max8925_rtc_info *info = dev_get_drvdata(dev);
unsigned char buf[TIME_NUM];
int ret;
ret = data_calc(buf, &alrm->time, TIME_NUM);
if (ret < 0)
goto out;
ret = max8925_bulk_write(info->rtc, MAX8925_ALARM0_SEC, TIME_NUM, buf);
if (ret < 0)
goto out;
if (alrm->enabled)
/* only enable alarm on year/month/day/hour/min/sec */
ret = max8925_reg_write(info->rtc, MAX8925_ALARM0_CNTL, 0x77);
else
ret = max8925_reg_write(info->rtc, MAX8925_ALARM0_CNTL, 0x0);
out:
return ret;
}
static const struct rtc_class_ops max8925_rtc_ops = {
.read_time = max8925_rtc_read_time,
.set_time = max8925_rtc_set_time,
.read_alarm = max8925_rtc_read_alarm,
.set_alarm = max8925_rtc_set_alarm,
};
static int max8925_rtc_probe(struct platform_device *pdev)
{
struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
struct max8925_rtc_info *info;
int ret;
info = devm_kzalloc(&pdev->dev, sizeof(struct max8925_rtc_info),
GFP_KERNEL);
if (!info)
return -ENOMEM;
info->chip = chip;
info->rtc = chip->rtc;
info->dev = &pdev->dev;
info->irq = platform_get_irq(pdev, 0);
ret = devm_request_threaded_irq(&pdev->dev, info->irq, NULL,
rtc_update_handler, IRQF_ONESHOT,
"rtc-alarm0", info);
if (ret < 0) {
dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
info->irq, ret);
return ret;
}
dev_set_drvdata(&pdev->dev, info);
/* XXX - isn't this redundant? */
platform_set_drvdata(pdev, info);
device_init_wakeup(&pdev->dev, 1);
info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max8925-rtc",
&max8925_rtc_ops, THIS_MODULE);
ret = PTR_ERR(info->rtc_dev);
if (IS_ERR(info->rtc_dev)) {
dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
return ret;
}
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int max8925_rtc_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
if (device_may_wakeup(dev))
chip->wakeup_flag |= 1 << MAX8925_IRQ_RTC_ALARM0;
return 0;
}
static int max8925_rtc_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
if (device_may_wakeup(dev))
chip->wakeup_flag &= ~(1 << MAX8925_IRQ_RTC_ALARM0);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(max8925_rtc_pm_ops, max8925_rtc_suspend, max8925_rtc_resume);
static struct platform_driver max8925_rtc_driver = {
.driver = {
.name = "max8925-rtc",
.pm = &max8925_rtc_pm_ops,
},
.probe = max8925_rtc_probe,
};
module_platform_driver(max8925_rtc_driver);
MODULE_DESCRIPTION("Maxim MAX8925 RTC driver");
MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
MODULE_LICENSE("GPL");
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