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Message-ID: <214f1451-2406-b298-e233-4939cae9e1f2@suse.de>
Date: Mon, 12 Apr 2021 09:45:36 +0200
From: Thomas Zimmermann <tzimmermann@...e.de>
To: KuoHsiang Chou <kuohsiang_chou@...eedtech.com>,
dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Cc: airlied@...hat.com, airlied@...ux.ie, daniel@...ll.ch,
jenmin_yuan@...eedtech.com, arc_sung@...eedtech.com
Subject: Re: [PATCH v4] drm/ast: Fixed CVE for DP501
Hi
this patch produces a NULL-ptr deref as shown below. The chip is
detected as AST 2100.
Best regards
Thomas
==================================================================
[ 23.641896] BUG: KASAN: null-ptr-deref in
ast_device_create.cold+0x137/0x210 [ast]
[ 23.642257] Read of size 8 at addr 0000000000000610 by task
systemd-udevd/321
[ 23.642539]
[ 23.642696] CPU: 2 PID: 321 Comm: systemd-udevd Tainted: G
E 5.12.0-rc6-1-default+ #876
[ 23.643064] Hardware name: Sun Microsystems SUN FIRE X2270 M2/SUN
FIRE X2270 M2, BIOS 2.05 07/01/2010
[ 23.643432] Call Trace:
[ 23.643622] ? ast_device_create.cold+0x137/0x210 [ast]
[ 23.643898] dump_stack+0xa5/0xdc
[ 23.644119] kasan_report.cold+0x50/0x55
[ 23.644363] ? ast_device_create.cold+0x137/0x210 [ast]
[ 23.644657] ast_device_create.cold+0x137/0x210 [ast]
[ 23.644926] ? devres_get+0xe5/0x160
[ 23.645152] ? ast_detect_chip.isra.0+0x110/0x110 [ast]
[ 23.645474] ast_pci_probe+0x4c/0x90 [ast]
[ 23.645734] ? ast_kick_out_firmware_fb+0xd0/0xd0 [ast]
[ 23.646003] local_pci_probe+0x74/0xc0
[ 23.646249] pci_call_probe+0xb7/0x1d0
[ 23.646473] ? pci_pm_suspend_noirq+0x440/0x440
[ 23.646773] pci_device_probe+0x102/0x140
[ 23.646998] ? driver_sysfs_add+0xe2/0x150
[ 23.647245] really_probe+0x185/0x6c0
[ 23.647506] driver_probe_device+0x13f/0x1d0
[ 23.647762] device_driver_attach+0x114/0x120
[ 23.648010] ? device_driver_attach+0x120/0x120
[ 23.648254] __driver_attach+0xb0/0x1a0
[ 23.648497] ? device_driver_attach+0x120/0x120
[ 23.648739] bus_for_each_dev+0xdd/0x120
[ 23.648971] ? subsys_dev_iter_exit+0x10/0x10
[ 23.649256] bus_add_driver+0x1fb/0x2e0
[ 23.649514] driver_register+0x10f/0x190
[ 23.649752] ? 0xffffffffc05fd000
[ 23.649971] do_one_initcall+0xbb/0x3a0
[ 23.650206] ? trace_event_raw_event_initcall_finish+0x120/0x120
[ 23.650485] ? mark_held_locks+0x23/0x90
[ 23.650718] ? lock_is_held_type+0xe5/0x110
[ 23.650982] ? rcu_read_lock_sched_held+0x3f/0x80
[ 23.651223] ? kasan_unpoison+0x21/0x50
[ 23.651483] do_init_module+0xfd/0x3c0
[ 23.651720] load_module+0xcf2/0xd70
[ 23.651909] ? layout_and_allocate+0x260/0x260
[ 23.652082] ? seccomp_run_filters+0x97/0x1d0
[ 23.652309] ? kernel_read_file_from_fd+0x4b/0x90
[ 23.652584] __do_sys_finit_module+0xff/0x180
[ 23.652824] ? __ia32_sys_init_module+0x40/0x40
[ 23.653198] ? syscall_trace_enter.constprop.0+0x99/0x240
[ 23.653477] do_syscall_64+0x33/0x80
[ 23.653693] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 23.653934] RIP: 0033:0x7f793ecc23dd
[ 23.654147] Code: c2 0c 00 0f 05 eb a9 66 0f 1f 44 00 00 f3 0f 1e fa
48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f
05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 63 7a 0c 00 f7 d8 64 89 01 48
[ 23.654749] RSP: 002b:00007ffdc09a08c8 EFLAGS: 00000246 ORIG_RAX:
0000000000000139
[ 23.655092] RAX: ffffffffffffffda RBX: 000055e8dd73b8d0 RCX:
00007f793ecc23dd
[ 23.655375] RDX: 0000000000000000 RSI: 00007f793ede33a3 RDI:
0000000000000010
[ 23.655658] RBP: 0000000000020000 R08: 0000000000000000 R09:
000055e8dd746750
[ 23.655941] R10: 0000000000000010 R11: 0000000000000246 R12:
00007f793ede33a3
[ 23.656224] R13: 000055e8dd743ff0 R14: 0000000000000000 R15:
000055e8dd746a80
[ 23.656603]
==================================================================
Am 08.04.21 um 11:30 schrieb KuoHsiang Chou:
> [Bug][DP501]
> If ASPEED P2A (PCI to AHB) bridge is disabled and disallowed for
> CVE_2019_6260 item3, and then the monitor's EDID is unable read through
> Parade DP501.
> The reason is the DP501's FW is mapped to BMC addressing space rather
> than Host addressing space.
> The resolution is that using "pci_iomap_range()" maps to DP501's FW that
> stored on the end of FB (Frame Buffer).
> In this case, FrameBuffer reserves the last 2MB used for the image of
> DP501.
>
> Signed-off-by: KuoHsiang Chou <kuohsiang_chou@...eedtech.com>
> Reported-by: kernel test robot <lkp@...el.com>
> ---
> drivers/gpu/drm/ast/ast_dp501.c | 139 +++++++++++++++++++++++---------
> drivers/gpu/drm/ast/ast_drv.h | 12 +++
> drivers/gpu/drm/ast/ast_main.c | 8 ++
> 3 files changed, 123 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/gpu/drm/ast/ast_dp501.c b/drivers/gpu/drm/ast/ast_dp501.c
> index 88121c0e0..cd93c44f2 100644
> --- a/drivers/gpu/drm/ast/ast_dp501.c
> +++ b/drivers/gpu/drm/ast/ast_dp501.c
> @@ -189,6 +189,9 @@ bool ast_backup_fw(struct drm_device *dev, u8 *addr, u32 size)
> u32 i, data;
> u32 boot_address;
>
> + if (ast->config_mode != ast_use_p2a)
> + return false;
> +
> data = ast_mindwm(ast, 0x1e6e2100) & 0x01;
> if (data) {
> boot_address = get_fw_base(ast);
> @@ -207,6 +210,9 @@ static bool ast_launch_m68k(struct drm_device *dev)
> u8 *fw_addr = NULL;
> u8 jreg;
>
> + if (ast->config_mode != ast_use_p2a)
> + return false;
> +
> data = ast_mindwm(ast, 0x1e6e2100) & 0x01;
> if (!data) {
>
> @@ -271,25 +277,55 @@ u8 ast_get_dp501_max_clk(struct drm_device *dev)
> struct ast_private *ast = to_ast_private(dev);
> u32 boot_address, offset, data;
> u8 linkcap[4], linkrate, linklanes, maxclk = 0xff;
> + u32 *plinkcap;
>
> - boot_address = get_fw_base(ast);
> -
> - /* validate FW version */
> - offset = 0xf000;
> - data = ast_mindwm(ast, boot_address + offset);
> - if ((data & 0xf0) != 0x10) /* version: 1x */
> - return maxclk;
> -
> - /* Read Link Capability */
> - offset = 0xf014;
> - *(u32 *)linkcap = ast_mindwm(ast, boot_address + offset);
> - if (linkcap[2] == 0) {
> - linkrate = linkcap[0];
> - linklanes = linkcap[1];
> - data = (linkrate == 0x0a) ? (90 * linklanes) : (54 * linklanes);
> - if (data > 0xff)
> - data = 0xff;
> - maxclk = (u8)data;
> + if (ast->config_mode == ast_use_p2a) {
> + boot_address = get_fw_base(ast);
> +
> + /* validate FW version */
> + offset = AST_DP501_GBL_VERSION;
> + data = ast_mindwm(ast, boot_address + offset);
> + if ((data & AST_DP501_FW_VERSION_MASK) != AST_DP501_FW_VERSION_1) /* version: 1x */
> + return maxclk;
> +
> + /* Read Link Capability */
> + offset = AST_DP501_LINKRATE;
> + plinkcap = (u32 *)linkcap;
> + *plinkcap = ast_mindwm(ast, boot_address + offset);
> + if (linkcap[2] == 0) {
> + linkrate = linkcap[0];
> + linklanes = linkcap[1];
> + data = (linkrate == 0x0a) ? (90 * linklanes) : (54 * linklanes);
> + if (data > 0xff)
> + data = 0xff;
> + maxclk = (u8)data;
> + }
> + } else {
> + if (!ast->dp501_fw_buf)
> + return AST_DP501_DEFAULT_DCLK; /* 1024x768 as default */
> +
> + /* dummy read */
> + offset = 0x0000;
> + data = readl(ast->dp501_fw_buf + offset);
> +
> + /* validate FW version */
> + offset = AST_DP501_GBL_VERSION;
> + data = readl(ast->dp501_fw_buf + offset);
> + if ((data & AST_DP501_FW_VERSION_MASK) != AST_DP501_FW_VERSION_1) /* version: 1x */
> + return maxclk;
> +
> + /* Read Link Capability */
> + offset = AST_DP501_LINKRATE;
> + plinkcap = (u32 *)linkcap;
> + *plinkcap = readl(ast->dp501_fw_buf + offset);
> + if (linkcap[2] == 0) {
> + linkrate = linkcap[0];
> + linklanes = linkcap[1];
> + data = (linkrate == 0x0a) ? (90 * linklanes) : (54 * linklanes);
> + if (data > 0xff)
> + data = 0xff;
> + maxclk = (u8)data;
> + }
> }
> return maxclk;
> }
> @@ -298,26 +334,57 @@ bool ast_dp501_read_edid(struct drm_device *dev, u8 *ediddata)
> {
> struct ast_private *ast = to_ast_private(dev);
> u32 i, boot_address, offset, data;
> + u32 *pEDIDidx;
>
> - boot_address = get_fw_base(ast);
> -
> - /* validate FW version */
> - offset = 0xf000;
> - data = ast_mindwm(ast, boot_address + offset);
> - if ((data & 0xf0) != 0x10)
> - return false;
> -
> - /* validate PnP Monitor */
> - offset = 0xf010;
> - data = ast_mindwm(ast, boot_address + offset);
> - if (!(data & 0x01))
> - return false;
> + if (ast->config_mode == ast_use_p2a) {
> + boot_address = get_fw_base(ast);
>
> - /* Read EDID */
> - offset = 0xf020;
> - for (i = 0; i < 128; i += 4) {
> - data = ast_mindwm(ast, boot_address + offset + i);
> - *(u32 *)(ediddata + i) = data;
> + /* validate FW version */
> + offset = AST_DP501_GBL_VERSION;
> + data = ast_mindwm(ast, boot_address + offset);
> + if ((data & AST_DP501_FW_VERSION_MASK) != AST_DP501_FW_VERSION_1)
> + return false;
> +
> + /* validate PnP Monitor */
> + offset = AST_DP501_PNPMONITOR;
> + data = ast_mindwm(ast, boot_address + offset);
> + if (!(data & AST_DP501_PNP_CONNECTED))
> + return false;
> +
> + /* Read EDID */
> + offset = AST_DP501_EDID_DATA;
> + for (i = 0; i < 128; i += 4) {
> + data = ast_mindwm(ast, boot_address + offset + i);
> + pEDIDidx = (u32 *)(ediddata + i);
> + *pEDIDidx = data;
> + }
> + } else {
> + if (!ast->dp501_fw_buf)
> + return false;
> +
> + /* dummy read */
> + offset = 0x0000;
> + data = readl(ast->dp501_fw_buf + offset);
> +
> + /* validate FW version */
> + offset = AST_DP501_GBL_VERSION;
> + data = readl(ast->dp501_fw_buf + offset);
> + if ((data & AST_DP501_FW_VERSION_MASK) != AST_DP501_FW_VERSION_1)
> + return false;
> +
> + /* validate PnP Monitor */
> + offset = AST_DP501_PNPMONITOR;
> + data = readl(ast->dp501_fw_buf + offset);
> + if (!(data & AST_DP501_PNP_CONNECTED))
> + return false;
> +
> + /* Read EDID */
> + offset = AST_DP501_EDID_DATA;
> + for (i = 0; i < 128; i += 4) {
> + data = readl(ast->dp501_fw_buf + offset + i);
> + pEDIDidx = (u32 *)(ediddata + i);
> + *pEDIDidx = data;
> + }
> }
>
> return true;
> diff --git a/drivers/gpu/drm/ast/ast_drv.h b/drivers/gpu/drm/ast/ast_drv.h
> index e82ab8628..911f9f414 100644
> --- a/drivers/gpu/drm/ast/ast_drv.h
> +++ b/drivers/gpu/drm/ast/ast_drv.h
> @@ -150,6 +150,7 @@ struct ast_private {
>
> void __iomem *regs;
> void __iomem *ioregs;
> + void __iomem *dp501_fw_buf;
>
> enum ast_chip chip;
> bool vga2_clone;
> @@ -325,6 +326,17 @@ int ast_mode_config_init(struct ast_private *ast);
> #define AST_MM_ALIGN_SHIFT 4
> #define AST_MM_ALIGN_MASK ((1 << AST_MM_ALIGN_SHIFT) - 1)
>
> +#define AST_DP501_FW_VERSION_MASK GENMASK(7, 4)
> +#define AST_DP501_FW_VERSION_1 BIT(4)
> +#define AST_DP501_PNP_CONNECTED BIT(1)
> +
> +#define AST_DP501_DEFAULT_DCLK 65
> +
> +#define AST_DP501_GBL_VERSION 0xf000
> +#define AST_DP501_PNPMONITOR 0xf010
> +#define AST_DP501_LINKRATE 0xf014
> +#define AST_DP501_EDID_DATA 0xf020
> +
> int ast_mm_init(struct ast_private *ast);
>
> /* ast post */
> diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
> index 0ac3c2039..dbf5224ab 100644
> --- a/drivers/gpu/drm/ast/ast_main.c
> +++ b/drivers/gpu/drm/ast/ast_main.c
> @@ -450,6 +450,14 @@ struct ast_private *ast_device_create(const struct
drm_driver *drv,
> if (ret)
> return ERR_PTR(ret);
>
> + /* map reserved buffer */
> + ast->dp501_fw_buf = NULL;
> + if (dev->vram_mm->vram_size < pci_resource_len(dev->pdev, 0)) {
> + ast->dp501_fw_buf = pci_iomap_range(dev->pdev, 0, dev->vram_mm->vram_size, 0);
> + if (!ast->dp501_fw_buf)
> + drm_info(dev, "failed to map reserved buffer!\n");
> + }
> +
> ret = ast_mode_config_init(ast);
> if (ret)
> return ERR_PTR(ret);
> --
> 2.18.4
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer
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