Commit graph

10,103 commits

Author SHA1 Message Date
Thomas Zimmermann
f73b3653a4 fbcon: Remove struct fbcon_display.inverse
[ Upstream commit 30baedeeea ]

The field inverse in struct fbcon_display is unused. Remove it.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: <stable@vger.kernel.org> # v6.0+
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:21:58 -05:00
René Rebe
8225baf882 fbdev: ffb: fix corrupted video output on Sun FFB1
[ Upstream commit b28da0d092 ]

Fix Sun FFB1 corrupted video out ([1] and [2]) by disabling overlay and
initializing window mode to a known state. The issue never appeared on
my FFB2+/vertical nor Elite3D/M6. It could also depend on the PROM
version.

/SUNW,ffb@1e,0: FFB at 000001fc00000000, type 11, DAC pnum[236c] rev[10] manuf_rev[4]
X (II) /dev/fb0: Detected FFB1, Z-buffer, Single-buffered.
X (II) /dev/fb0: BT9068 (PAC1) ramdac detected (with normal cursor control)
X (II) /dev/fb0: Detected Creator/Creator3D

[1] https://www.instagram.com/p/DUTcSmSjSem/
[2] https://chaos.social/@ReneRebe/116023241660154102

Signed-off-by: René Rebe <rene@exactco.de>
Cc: stable@kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:21:58 -05:00
Weigang He
d6f34bbff0 fbdev: of: display_timing: fix refcount leak in of_get_display_timings()
[ Upstream commit eacf9840ae ]

of_parse_phandle() returns a device_node with refcount incremented,
which is stored in 'entry' and then copied to 'native_mode'. When the
error paths at lines 184 or 192 jump to 'entryfail', native_mode's
refcount is not decremented, causing a refcount leak.

Fix this by changing the goto target from 'entryfail' to 'timingfail',
which properly calls of_node_put(native_mode) before cleanup.

Fixes: cc3f414cf2 ("video: add of helper for display timings/videomode")
Cc: stable@vger.kernel.org
Signed-off-by: Weigang He <geoffreyhe2@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:21:57 -05:00
Thomas Fourier
f47d5b9e8a fbdev: vt8500lcdfb: fix missing dma_free_coherent()
[ Upstream commit 88b3b99243 ]

fbi->fb.screen_buffer is allocated with dma_alloc_coherent() but is not
freed if the error path is reached.

Fixes: e7b995371f ("video: vt8500: Add devicetree support for vt8500-fb and wm8505-fb")
Cc: <stable@vger.kernel.org>
Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:21:57 -05:00
Andrey Vatoropin
0b038c0be6 fbcon: check return value of con2fb_acquire_newinfo()
[ Upstream commit 011a050280 ]

If fbcon_open() fails when called from con2fb_acquire_newinfo() then
info->fbcon_par pointer remains NULL which is later dereferenced.

Add check for return value of the function con2fb_acquire_newinfo() to
avoid it.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: d1baa4ffa6 ("fbcon: set_con2fb_map fixes")
Cc: stable@vger.kernel.org
Signed-off-by: Andrey Vatoropin <a.vatoropin@crpt.ru>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:21:57 -05:00
Barnabás Czémán
f076d69aae backlight: qcom-wled: Change PM8950 WLED configurations
[ Upstream commit 83333aa974 ]

PMI8950 WLED needs same configurations as PMI8994 WLED.

Fixes: 10258bf453 ("backlight: qcom-wled: Add PMI8950 compatible")
Signed-off-by: Barnabás Czémán <barnabas.czeman@mainlining.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Link: https://patch.msgid.link/20260116-pmi8950-wled-v3-4-e6c93de84079@mainlining.org
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:20:33 -05:00
Barnabás Czémán
92de557d5d backlight: qcom-wled: Support ovp values for PMI8994
[ Upstream commit f29f972a6e ]

WLED4 found in PMI8994 supports different ovp values.

Fixes: 6fc632d3e3 ("video: backlight: qcom-wled: Add PMI8994 compatible")
Signed-off-by: Barnabás Czémán <barnabas.czeman@mainlining.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Link: https://patch.msgid.link/20260116-pmi8950-wled-v3-2-e6c93de84079@mainlining.org
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:20:33 -05:00
Felix Gu
762a268189 fbdev: au1200fb: Fix a memory leak in au1200fb_drv_probe()
[ Upstream commit ce4e25198a ]

In au1200fb_drv_probe(), when platform_get_irq fails(), it directly
returns from the function with an error code, which causes a memory
leak.

Replace it with a goto label to ensure proper cleanup.

Fixes: 4e88761f5f ("fbdev: au1200fb: Fix missing IRQ check in au1200fb_drv_probe")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:20:25 -05:00
Felix Gu
f620398f0d fbdev: of_display_timing: Fix device node reference leak in of_get_display_timings()
[ Upstream commit c39ee2d264 ]

Use for_each_child_of_node_scoped instead of for_each_child_of_node
to ensure automatic of_node_put on early exit paths, preventing
device node reference leak.

Fixes: cc3f414cf2 ("video: add of helper for display timings/videomode")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:20:25 -05:00
Greg Kroah-Hartman
52917e265a fbdev: smscufx: properly copy ioctl memory to kernelspace
commit 120adae7b4 upstream.

The UFX_IOCTL_REPORT_DAMAGE ioctl does not properly copy data from
userspace to kernelspace, and instead directly references the memory,
which can cause problems if invalid data is passed from userspace.  Fix
this all up by correctly copying the memory before accessing it within
the kernel.

Reported-by: Tianchu Chen <flynnnchen@tencent.com>
Cc: stable <stable@kernel.org>
Cc: Steve Glendinning <steve.glendinning@shawell.net>
Cc: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-02-19 16:29:55 +01:00
Guangshuo Li
9efa0dc462 fbdev: rivafb: fix divide error in nv3_arb()
commit 0209e21e3c upstream.

A userspace program can trigger the RIVA NV3 arbitration code by calling
the FBIOPUT_VSCREENINFO ioctl on /dev/fb*. When doing so, the driver
recomputes FIFO arbitration parameters in nv3_arb(), using state->mclk_khz
(derived from the PRAMDAC MCLK PLL) as a divisor without validating it
first.

In a normal setup, state->mclk_khz is provided by the real hardware and is
non-zero. However, an attacker can construct a malicious or misconfigured
device (e.g. a crafted/emulated PCI device) that exposes a bogus PLL
configuration, causing state->mclk_khz to become zero.  Once
nv3_get_param() calls nv3_arb(), the division by state->mclk_khz in the gns
calculation causes a divide error and crashes the kernel.

Fix this by checking whether state->mclk_khz is zero and bailing out before
doing the division.

The following log reveals it:

rivafb: setting virtual Y resolution to 2184
divide error: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 0 PID: 2187 Comm: syz-executor.0 Not tainted 5.18.0-rc1+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
RIP: 0010:nv3_arb drivers/video/fbdev/riva/riva_hw.c:439 [inline]
RIP: 0010:nv3_get_param+0x3ab/0x13b0 drivers/video/fbdev/riva/riva_hw.c:546
Call Trace:
  nv3CalcArbitration.constprop.0+0x255/0x460 drivers/video/fbdev/riva/riva_hw.c:603
  nv3UpdateArbitrationSettings drivers/video/fbdev/riva/riva_hw.c:637 [inline]
  CalcStateExt+0x447/0x1b90 drivers/video/fbdev/riva/riva_hw.c:1246
  riva_load_video_mode+0x8a9/0xea0 drivers/video/fbdev/riva/fbdev.c:779
  rivafb_set_par+0xc0/0x5f0 drivers/video/fbdev/riva/fbdev.c:1196
  fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1033
  do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1109
  fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1188
  __x64_sys_ioctl+0x122/0x190 fs/ioctl.c:856

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-02-19 16:29:55 +01:00
René Rebe
a135dfe84a fbdev: tcx.c fix mem_map to correct smem_start offset
commit 35fa2b4bf9 upstream.

403ae52ac0 ("sparc: fix drivers/video/tcx.c warning") changed the
physbase initializing breaking the user-space mmap, e.g. for Xorg
entirely.

Fix fbdev mmap table so the sbus mmap helper work correctly, and
not try to map vastly (physbase) offset memory.

Fixes: 403ae52ac0 ("sparc: fix drivers/video/tcx.c warning")
Cc: <stable@vger.kernel.org>
Signed-off-by: René Rebe <rene@exactco.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-01-08 10:14:45 +01:00
Thorsten Blum
b58f85225b fbdev: pxafb: Fix multiple clamped values in pxafb_adjust_timing
commit 0155e868cb upstream.

The variables were never clamped because the return value of clamp_val()
was not used. Fix this by assigning the clamped values, and use clamp()
instead of clamp_val().

Cc: stable@vger.kernel.org
Fixes: 3f16ff608a ("[ARM] pxafb: cleanup of the timing checking code")
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-01-08 10:14:44 +01:00
Rene Rebe
77c8170a62 fbdev: gbefb: fix to use physical address instead of dma address
commit e3f44742bb upstream.

While debuggigng why X would not start on mips64 Sgi/O2 I found the
phys adress being off. Turns out the gbefb passed the internal
dma_addr as phys. May be broken pre git history. Fix by converting
dma_to_phys.

Signed-off-by: René Rebe <rene@exactco.de>
Cc: <stable@vger.kernel.org> # v4.0+
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-01-08 10:14:44 +01:00
Abdun Nihaal
d4b20e53b6 fbdev: ssd1307fb: fix potential page leak in ssd1307fb_probe()
[ Upstream commit 164312662a ]

The page allocated for vmem using __get_free_pages() is not freed on the
error paths after it. Fix that by adding a corresponding __free_pages()
call to the error path.

Fixes: facd94bc45 ("fbdev: ssd1307fb: Allocate page aligned video memory.")
Signed-off-by: Abdun Nihaal <nihaal@cse.iitm.ac.in>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-18 13:55:15 +01:00
Luca Ceresoli
0e63ea4378 backlight: led-bl: Add devlink to supplier LEDs
[ Upstream commit 9341d6698f ]

LED Backlight is a consumer of one or multiple LED class devices, but
devlink is currently unable to create correct supplier-producer links when
the supplier is a class device. It creates instead a link where the
supplier is the parent of the expected device.

One consequence is that removal order is not correctly enforced.

Issues happen for example with the following sections in a device tree
overlay:

    // An LED driver chip
    pca9632@62 {
        compatible = "nxp,pca9632";
        reg = <0x62>;

	// ...

        addon_led_pwm: led-pwm@3 {
            reg = <3>;
            label = "addon:led:pwm";
        };
    };

    backlight-addon {
        compatible = "led-backlight";
        leds = <&addon_led_pwm>;
        brightness-levels = <255>;
        default-brightness-level = <255>;
    };

In this example, the devlink should be created between the backlight-addon
(consumer) and the pca9632@62 (supplier). Instead it is created between the
backlight-addon (consumer) and the parent of the pca9632@62, which is
typically the I2C bus adapter.

On removal of the above overlay, the LED driver can be removed before the
backlight device, resulting in:

    Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010
    ...
    Call trace:
     led_put+0xe0/0x140
     devm_led_release+0x6c/0x98

Another way to reproduce the bug without any device tree overlays is
unbinding the LED class device (pca9632@62) before unbinding the consumer
(backlight-addon):

  echo 11-0062 >/sys/bus/i2c/drivers/leds-pca963x/unbind
  echo ...backlight-dock >/sys/bus/platform/drivers/led-backlight/unbind

Fix by adding a devlink between the consuming led-backlight device and the
supplying LED device, as other drivers and subsystems do as well.

Fixes: ae232e45ac ("backlight: add led-backlight driver")
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Reviewed-by: Herve Codina <herve.codina@bootlin.com>
Tested-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Link: https://patch.msgid.link/20250519-led-backlight-add-devlink-to-supplier-class-device-v6-1-845224aeb2ce@bootlin.com
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-18 13:55:07 +01:00
Thomas Zimmermann
482330f826 drm, fbcon, vga_switcheroo: Avoid race condition in fbcon setup
[ Upstream commit eb76d0f555 ]

Protect vga_switcheroo_client_fb_set() with console lock. Avoids OOB
access in fbcon_remap_all(). Without holding the console lock the call
races with switching outputs.

VGA switcheroo calls fbcon_remap_all() when switching clients. The fbcon
function uses struct fb_info.node, which is set by register_framebuffer().
As the fb-helper code currently sets up VGA switcheroo before registering
the framebuffer, the value of node is -1 and therefore not a legal value.
For example, fbcon uses the value within set_con2fb_map() [1] as an index
into an array.

Moving vga_switcheroo_client_fb_set() after register_framebuffer() can
result in VGA switching that does not switch fbcon correctly.

Therefore move vga_switcheroo_client_fb_set() under fbcon_fb_registered(),
which already holds the console lock. Fbdev calls fbcon_fb_registered()
from within register_framebuffer(). Serializes the helper with VGA
switcheroo's call to fbcon_remap_all().

Although vga_switcheroo_client_fb_set() takes an instance of struct fb_info
as parameter, it really only needs the contained fbcon state. Moving the
call to fbcon initialization is therefore cleaner than before. Only amdgpu,
i915, nouveau and radeon support vga_switcheroo. For all other drivers,
this change does nothing.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://elixir.bootlin.com/linux/v6.17/source/drivers/video/fbdev/core/fbcon.c#L2942 # [1]
Fixes: 6a9ee8af34 ("vga_switcheroo: initial implementation (v15)")
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Cc: dri-devel@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Cc: <stable@vger.kernel.org> # v2.6.34+
Link: https://patch.msgid.link/20251105161549.98836-1-tzimmermann@suse.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-12-07 06:25:03 +09:00
Albin Babu Varghese
15ba9acafb fbdev: Add bounds checking in bit_putcs to fix vmalloc-out-of-bounds
[ Upstream commit 3637d34b35 ]

Add bounds checking to prevent writes past framebuffer boundaries when
rendering text near screen edges. Return early if the Y position is off-screen
and clip image height to screen boundary. Break from the rendering loop if the
X position is off-screen. When clipping image width to fit the screen, update
the character count to match the clipped width to prevent buffer size
mismatches.

Without the character count update, bit_putcs_aligned and bit_putcs_unaligned
receive mismatched parameters where the buffer is allocated for the clipped
width but cnt reflects the original larger count, causing out-of-bounds writes.

Reported-by: syzbot+48b0652a95834717f190@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=48b0652a95834717f190
Suggested-by: Helge Deller <deller@gmx.de>
Tested-by: syzbot+48b0652a95834717f190@syzkaller.appspotmail.com
Signed-off-by: Albin Babu Varghese <albinbabuvarghese20@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-11-13 15:34:35 -05:00
Svyatoslav Ryhel
ffd87e7867 video: backlight: lp855x_bl: Set correct EPROM start for LP8556
[ Upstream commit 07c7efda24 ]

According to LP8556 datasheet EPROM region starts at 0x98 so adjust value
in the driver accordingly.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250909074304.92135-2-clamor95@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-11-13 15:34:06 -05:00
Miaoqian Lin
3ea7b3a697 fbdev: valkyriefb: Fix reference count leak in valkyriefb_init
commit eb53368f8d upstream.

The of_find_node_by_name() function returns a device tree node with its
reference count incremented. The caller is responsible for calling
of_node_put() to release this reference when done.

Found via static analysis.

Fixes: cc5d0189b9 ("[PATCH] powerpc: Remove device_node addrs/n_addr")
Cc: stable@vger.kernel.org
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-11-13 15:33:55 -05:00
Florian Fuchs
a22bcb7f10 fbdev: pvr2fb: Fix leftover reference to ONCHIP_NR_DMA_CHANNELS
commit 5f566c0ac5 upstream.

Commit e24cca19ba ("sh: Kill off MAX_DMA_ADDRESS leftovers.") removed
the define ONCHIP_NR_DMA_CHANNELS. So that the leftover reference needs
to be replaced by CONFIG_NR_ONCHIP_DMA_CHANNELS to compile successfully
with CONFIG_PVR2_DMA enabled.

Signed-off-by: Florian Fuchs <fuchsfl@gmail.com>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-11-13 15:33:55 -05:00
Junjie Cao
901f442270 fbdev: bitblit: bound-check glyph index in bit_putcs*
commit 18c4ef4e76 upstream.

bit_putcs_aligned()/unaligned() derived the glyph pointer from the
character value masked by 0xff/0x1ff, which may exceed the actual font's
glyph count and read past the end of the built-in font array.
Clamp the index to the actual glyph count before computing the address.

This fixes a global out-of-bounds read reported by syzbot.

Reported-by: syzbot+793cf822d213be1a74f2@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=793cf822d213be1a74f2
Tested-by: syzbot+793cf822d213be1a74f2@syzkaller.appspotmail.com
Signed-off-by: Junjie Cao <junjie.cao@intel.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-11-13 15:33:55 -05:00
Daniel Palmer
9280286e04 fbdev: atyfb: Check if pll_ops->init_pll failed
commit 7073c7fc8d upstream.

Actually check the return value from pll_ops->init_pll()
as it can return an error.

If the card's BIOS didn't run because it's not the primary VGA card
the fact that the xclk source is unsupported is printed as shown
below but the driver continues on regardless and on my machine causes
a hard lock up.

[   61.470088] atyfb 0000:03:05.0: enabling device (0080 -> 0083)
[   61.476191] atyfb: using auxiliary register aperture
[   61.481239] atyfb: 3D RAGE XL (Mach64 GR, PCI-33) [0x4752 rev 0x27]
[   61.487569] atyfb: 512K SGRAM (1:1), 14.31818 MHz XTAL, 230 MHz PLL, 83 Mhz MCLK, 63 MHz XCLK
[   61.496112] atyfb: Unsupported xclk source:  5.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Daniel Palmer <daniel@0x0f.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-11-13 15:33:55 -05:00
Quanmin Yan
c079d42f70 fbcon: Set fb_display[i]->mode to NULL when the mode is released
commit a1f3058930 upstream.

Recently, we discovered the following issue through syzkaller:

BUG: KASAN: slab-use-after-free in fb_mode_is_equal+0x285/0x2f0
Read of size 4 at addr ff11000001b3c69c by task syz.xxx
...
Call Trace:
 <TASK>
 dump_stack_lvl+0xab/0xe0
 print_address_description.constprop.0+0x2c/0x390
 print_report+0xb9/0x280
 kasan_report+0xb8/0xf0
 fb_mode_is_equal+0x285/0x2f0
 fbcon_mode_deleted+0x129/0x180
 fb_set_var+0xe7f/0x11d0
 do_fb_ioctl+0x6a0/0x750
 fb_ioctl+0xe0/0x140
 __x64_sys_ioctl+0x193/0x210
 do_syscall_64+0x5f/0x9c0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Based on experimentation and analysis, during framebuffer unregistration,
only the memory of fb_info->modelist is freed, without setting the
corresponding fb_display[i]->mode to NULL for the freed modes. This leads
to UAF issues during subsequent accesses. Here's an example of reproduction
steps:
1. With /dev/fb0 already registered in the system, load a kernel module
   to register a new device /dev/fb1;
2. Set fb1's mode to the global fb_display[] array (via FBIOPUT_CON2FBMAP);
3. Switch console from fb to VGA (to allow normal rmmod of the ko);
4. Unload the kernel module, at this point fb1's modelist is freed, leaving
   a wild pointer in fb_display[];
5. Trigger the bug via system calls through fb0 attempting to delete a mode
   from fb0.

Add a check in do_unregister_framebuffer(): if the mode to be freed exists
in fb_display[], set the corresponding mode pointer to NULL.

Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-11-13 15:33:55 -05:00
Finn Thain
f7cf0d7747 fbdev: Fix logic error in "offb" name match
commit 15df28699b upstream.

A regression was reported to me recently whereby /dev/fb0 had disappeared
from a PowerBook G3 Series "Wallstreet". The problem shows up when the
"video=ofonly" parameter is passed to the kernel, which is what the
bootloader does when "no video driver" is selected. The cause of the
problem is the "offb" string comparison, which got mangled when it got
refactored. Fix it.

Cc: stable@vger.kernel.org
Fixes: 93604a5ade ("fbdev: Handle video= parameter in video/cmdline.c")
Reported-and-tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@linux-m68k.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-19 16:33:49 +02:00
Janne Grunau
b1deb39cfd fbdev: simplefb: Fix use after free in simplefb_detach_genpds()
commit da1bb91352 upstream.

The pm_domain cleanup can not be devres managed as it uses struct
simplefb_par which is allocated within struct fb_info by
framebuffer_alloc(). This allocation is explicitly freed by
unregister_framebuffer() in simplefb_remove().
Devres managed cleanup runs after the device remove call and thus can no
longer access struct simplefb_par.
Call simplefb_detach_genpds() explicitly from simplefb_destroy() like
the cleanup functions for clocks and regulators.

Fixes an use after free on M2 Mac mini during
aperture_remove_conflicting_devices() using the downstream asahi kernel
with Debian's kernel config. For unknown reasons this started to
consistently dereference an invalid pointer in v6.16.3 based kernels.

[    6.736134] BUG: KASAN: slab-use-after-free in simplefb_detach_genpds+0x58/0x220
[    6.743545] Read of size 4 at addr ffff8000304743f0 by task (udev-worker)/227
[    6.750697]
[    6.752182] CPU: 6 UID: 0 PID: 227 Comm: (udev-worker) Tainted: G S                  6.16.3-asahi+ #16 PREEMPTLAZY
[    6.752186] Tainted: [S]=CPU_OUT_OF_SPEC
[    6.752187] Hardware name: Apple Mac mini (M2, 2023) (DT)
[    6.752189] Call trace:
[    6.752190]  show_stack+0x34/0x98 (C)
[    6.752194]  dump_stack_lvl+0x60/0x80
[    6.752197]  print_report+0x17c/0x4d8
[    6.752201]  kasan_report+0xb4/0x100
[    6.752206]  __asan_report_load4_noabort+0x20/0x30
[    6.752209]  simplefb_detach_genpds+0x58/0x220
[    6.752213]  devm_action_release+0x50/0x98
[    6.752216]  release_nodes+0xd0/0x2c8
[    6.752219]  devres_release_all+0xfc/0x178
[    6.752221]  device_unbind_cleanup+0x28/0x168
[    6.752224]  device_release_driver_internal+0x34c/0x470
[    6.752228]  device_release_driver+0x20/0x38
[    6.752231]  bus_remove_device+0x1b0/0x380
[    6.752234]  device_del+0x314/0x820
[    6.752238]  platform_device_del+0x3c/0x1e8
[    6.752242]  platform_device_unregister+0x20/0x50
[    6.752246]  aperture_detach_platform_device+0x1c/0x30
[    6.752250]  aperture_detach_devices+0x16c/0x290
[    6.752253]  aperture_remove_conflicting_devices+0x34/0x50
...
[    6.752343]
[    6.967409] Allocated by task 62:
[    6.970724]  kasan_save_stack+0x3c/0x70
[    6.974560]  kasan_save_track+0x20/0x40
[    6.978397]  kasan_save_alloc_info+0x40/0x58
[    6.982670]  __kasan_kmalloc+0xd4/0xd8
[    6.986420]  __kmalloc_noprof+0x194/0x540
[    6.990432]  framebuffer_alloc+0xc8/0x130
[    6.994444]  simplefb_probe+0x258/0x2378
...
[    7.054356]
[    7.055838] Freed by task 227:
[    7.058891]  kasan_save_stack+0x3c/0x70
[    7.062727]  kasan_save_track+0x20/0x40
[    7.066565]  kasan_save_free_info+0x4c/0x80
[    7.070751]  __kasan_slab_free+0x6c/0xa0
[    7.074675]  kfree+0x10c/0x380
[    7.077727]  framebuffer_release+0x5c/0x90
[    7.081826]  simplefb_destroy+0x1b4/0x2c0
[    7.085837]  put_fb_info+0x98/0x100
[    7.089326]  unregister_framebuffer+0x178/0x320
[    7.093861]  simplefb_remove+0x3c/0x60
[    7.097611]  platform_remove+0x60/0x98
[    7.101361]  device_remove+0xb8/0x160
[    7.105024]  device_release_driver_internal+0x2fc/0x470
[    7.110256]  device_release_driver+0x20/0x38
[    7.114529]  bus_remove_device+0x1b0/0x380
[    7.118628]  device_del+0x314/0x820
[    7.122116]  platform_device_del+0x3c/0x1e8
[    7.126302]  platform_device_unregister+0x20/0x50
[    7.131012]  aperture_detach_platform_device+0x1c/0x30
[    7.136157]  aperture_detach_devices+0x16c/0x290
[    7.140779]  aperture_remove_conflicting_devices+0x34/0x50
...

Reported-by: Daniel Huhardeaux <tech@tootai.net>
Cc: stable@vger.kernel.org
Fixes: 92a511a568 ("fbdev/simplefb: Add support for generic power-domains")
Signed-off-by: Janne Grunau <j@jannau.net>
Reviewed-by: Hans de Goede <hansg@kernel.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-15 12:00:23 +02:00
Thomas Zimmermann
51b8258efe fbcon: Fix OOB access in font allocation
commit 9b2f5ef00e upstream.

Commit 1a194e6c8e ("fbcon: fix integer overflow in fbcon_do_set_font")
introduced an out-of-bounds access by storing data and allocation sizes
in the same variable. Restore the old size calculation and use the new
variable 'alloc_size' for the allocation.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 1a194e6c8e ("fbcon: fix integer overflow in fbcon_do_set_font")
Reported-by: Jani Nikula <jani.nikula@linux.intel.com>
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/15020
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6201
Cc: Samasth Norway Ananda <samasth.norway.ananda@oracle.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: George Kennedy <george.kennedy@oracle.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Shixiong Ou <oushixiong@kylinos.cn>
Cc: Kees Cook <kees@kernel.org>
Cc: <stable@vger.kernel.org> # v5.9+
Cc: Zsolt Kajtar <soci@c64.rulez.org>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Qianqiang Liu <qianqiang.liu@163.com>
Link: https://lore.kernel.org/r/20250922134619.257684-1-tzimmermann@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-02 13:44:14 +02:00
Samasth Norway Ananda
4a4bac8695 fbcon: fix integer overflow in fbcon_do_set_font
commit 1a194e6c8e upstream.

Fix integer overflow vulnerabilities in fbcon_do_set_font() where font
size calculations could overflow when handling user-controlled font
parameters.

The vulnerabilities occur when:
1. CALC_FONTSZ(h, pitch, charcount) performs h * pith * charcount
   multiplication with user-controlled values that can overflow.
2. FONT_EXTRA_WORDS * sizeof(int) + size addition can also overflow
3. This results in smaller allocations than expected, leading to buffer
   overflows during font data copying.

Add explicit overflow checking using check_mul_overflow() and
check_add_overflow() kernel helpers to safety validate all size
calculations before allocation.

Signed-off-by: Samasth Norway Ananda <samasth.norway.ananda@oracle.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 39b3cffb8c ("fbcon: prevent user font height or width change from causing potential out-of-bounds access")
Cc: George Kennedy <george.kennedy@oracle.com>
Cc: stable <stable@vger.kernel.org>
Cc: syzbot+38a3699c7eaf165b97a6@syzkaller.appspotmail.com
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Shixiong Ou <oushixiong@kylinos.cn>
Cc: Kees Cook <kees@kernel.org>
Cc: <stable@vger.kernel.org> # v5.9+
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://lore.kernel.org/r/20250912170023.3931881-1-samasth.norway.ananda@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-02 13:44:14 +02:00
Helge Deller
25e39d8da1 Revert "vgacon: Add check for vc_origin address range in vgacon_scroll()"
commit e4fc307d8e upstream.

This reverts commit 864f9963ec.

The patch is wrong as it checks vc_origin against vc_screenbuf,
while in text mode it should compare against vga_vram_base.

As such it broke VGA text scrolling, which can be reproduced like this:
(1) boot a kernel that is configured to use text mode VGA-console
(2) type commands:  ls -l /usr/bin | less -S
(3) scroll up/down with cursor-down/up keys

Reported-by: Jari Ruusu <jariruusu@protonmail.com>
Cc: stable@vger.kernel.org
Cc: Yi Yang <yiyang13@huawei.com>
Cc: GONG Ruiqi <gongruiqi1@huawei.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-08-28 16:30:55 +02:00
Sravan Kumar Gundu
ed9b8e5016 fbdev: Fix vmalloc out-of-bounds write in fast_imageblit
commit af0db3c1f8 upstream.

This issue triggers when a userspace program does an ioctl
FBIOPUT_CON2FBMAP by passing console number and frame buffer number.
Ideally this maps console to frame buffer and updates the screen if
console is visible.

As part of mapping it has to do resize of console according to frame
buffer info. if this resize fails and returns from vc_do_resize() and
continues further. At this point console and new frame buffer are mapped
and sets display vars. Despite failure still it continue to proceed
updating the screen at later stages where vc_data is related to previous
frame buffer and frame buffer info and display vars are mapped to new
frame buffer and eventully leading to out-of-bounds write in
fast_imageblit(). This bheviour is excepted only when fg_console is
equal to requested console which is a visible console and updates screen
with invalid struct references in fbcon_putcs().

Reported-and-tested-by: syzbot+c4b7aa0513823e2ea880@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c4b7aa0513823e2ea880
Signed-off-by: Sravan Kumar Gundu <sravankumarlpu@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-08-20 18:30:54 +02:00
Yongzhen Zhang
806f85bdd3 fbdev: fix potential buffer overflow in do_register_framebuffer()
[ Upstream commit 523b84dc7c ]

The current implementation may lead to buffer overflow when:
1.  Unregistration creates NULL gaps in registered_fb[]
2.  All array slots become occupied despite num_registered_fb < FB_MAX
3.  The registration loop exceeds array bounds

Add boundary check to prevent registered_fb[FB_MAX] access.

Signed-off-by: Yongzhen Zhang <zhangyongzhen@kylinos.cn>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-08-20 18:30:40 +02:00
Chenyuan Yang
40f0a51f6c fbdev: imxfb: Check fb_add_videomode to prevent null-ptr-deref
[ Upstream commit da11e6a30e ]

fb_add_videomode() can fail with -ENOMEM when its internal kmalloc() cannot
allocate a struct fb_modelist.  If that happens, the modelist stays empty but
the driver continues to register.  Add a check for its return value to prevent
poteintial null-ptr-deref, which is similar to the commit 17186f1f90 ("fbdev:
Fix do_register_framebuffer to prevent null-ptr-deref in fb_videomode_to_var").

Fixes: 1b6c79361b ("video: imxfb: Add DT support")
Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-08-15 12:13:57 +02:00
Shixiong Ou
69be0a3c4e fbcon: Fix outdated registered_fb reference in comment
[ Upstream commit 0f168e7be6 ]

The variable was renamed to fbcon_registered_fb, but this comment was
not updated along with the change. Correct it to avoid confusion.

Signed-off-by: Shixiong Ou <oushixiong@kylinos.cn>
Fixes: efc3acbc10 ("fbcon: Maintain a private array of fb_info")
[sima: Add Fixes: line.]
Signed-off-by: Simona Vetter <simona.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20250709103438.572309-1-oushixiong1025@163.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-08-15 12:13:42 +02:00
Kees Cook
f28f1f578c fbcon: Make sure modelist not set on unregistered console
[ Upstream commit cedc1b6339 ]

It looks like attempting to write to the "store_modes" sysfs node will
run afoul of unregistered consoles:

UBSAN: array-index-out-of-bounds in drivers/video/fbdev/core/fbcon.c:122:28
index -1 is out of range for type 'fb_info *[32]'
...
 fbcon_info_from_console+0x192/0x1a0 drivers/video/fbdev/core/fbcon.c:122
 fbcon_new_modelist+0xbf/0x2d0 drivers/video/fbdev/core/fbcon.c:3048
 fb_new_modelist+0x328/0x440 drivers/video/fbdev/core/fbmem.c:673
 store_modes+0x1c9/0x3e0 drivers/video/fbdev/core/fbsysfs.c:113
 dev_attr_store+0x55/0x80 drivers/base/core.c:2439

static struct fb_info *fbcon_registered_fb[FB_MAX];
...
static signed char con2fb_map[MAX_NR_CONSOLES];
...
static struct fb_info *fbcon_info_from_console(int console)
...
        return fbcon_registered_fb[con2fb_map[console]];

If con2fb_map contains a -1 things go wrong here. Instead, return NULL,
as callers of fbcon_info_from_console() are trying to compare against
existing "info" pointers, so error handling should kick in correctly.

Reported-by: syzbot+a7d4444e7b6e743572f7@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/679d0a8f.050a0220.163cdc.000c.GAE@google.com/
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-27 11:11:35 +01:00
Thomas Zimmermann
acbe1597e3 dummycon: Trigger redraw when switching consoles with deferred takeover
commit 03bcbbb399 upstream.

Signal vt subsystem to redraw console when switching to dummycon
with deferred takeover enabled. Makes the console switch to fbcon
and displays the available output.

With deferred takeover enabled, dummycon acts as the placeholder
until the first output to the console happens. At that point, fbcon
takes over. If the output happens while dummycon is not active, it
cannot inform fbcon. This is the case if the vt subsystem runs in
graphics mode.

A typical graphical boot starts plymouth, a display manager and a
compositor; all while leaving out dummycon. Switching to a text-mode
console leaves the console with dummycon even if a getty terminal
has been started.

Returning true from dummycon's con_switch helper signals the vt
subsystem to redraw the screen. If there's output available dummycon's
con_putc{s} helpers trigger deferred takeover of fbcon, which sets a
display mode and displays the output. If no output is available,
dummycon remains active.

v2:
- make the comment slightly more verbose (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reported-by: Andrei Borzenkov <arvidjaar@gmail.com>
Closes: https://bugzilla.suse.com/show_bug.cgi?id=1242191
Tested-by: Andrei Borzenkov <arvidjaar@gmail.com>
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Fixes: 83d83bebf4 ("console/fbcon: Add support for deferred console takeover")
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v4.19+
Link: https://lore.kernel.org/r/20250520071418.8462-1-tzimmermann@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27 11:11:26 +01:00
Thomas Zimmermann
5c70e3ad85 video: screen_info: Relocate framebuffers behind PCI bridges
commit 2f29b5c231 upstream.

Apply PCI host-bridge window offsets to screen_info framebuffers. Fixes
invalid access to I/O memory.

Resources behind a PCI host bridge can be relocated by a certain offset
in the kernel's CPU address range used for I/O. The framebuffer memory
range stored in screen_info refers to the CPU addresses as seen during
boot (where the offset is 0). During boot up, firmware may assign a
different memory offset to the PCI host bridge and thereby relocating
the framebuffer address of the PCI graphics device as seen by the kernel.
The information in screen_info must be updated as well.

The helper pcibios_bus_to_resource() performs the relocation of the
screen_info's framebuffer resource (given in PCI bus addresses). The
result matches the I/O-memory resource of the PCI graphics device (given
in CPU addresses). As before, we store away the information necessary to
later update the information in screen_info itself.

Commit 78aa89d1df ("firmware/sysfb: Update screen_info for relocated
EFI framebuffers") added the code for updating screen_info. It is based
on similar functionality that pre-existed in efifb. Efifb uses a pointer
to the PCI resource, while the newer code does a memcpy of the region.
Hence efifb sees any updates to the PCI resource and avoids the issue.

v3:
- Only use struct pci_bus_region for PCI bus addresses (Bjorn)
- Clarify address semantics in commit messages and comments (Bjorn)
v2:
- Fixed tags (Takashi, Ivan)
- Updated information on efifb

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reported-by: "Ivan T. Ivanov" <iivanov@suse.de>
Closes: https://bugzilla.suse.com/show_bug.cgi?id=1240696
Tested-by: "Ivan T. Ivanov" <iivanov@suse.de>
Fixes: 78aa89d1df ("firmware/sysfb: Update screen_info for relocated EFI framebuffers")
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v6.9+
Link: https://lore.kernel.org/r/20250528080234.7380-1-tzimmermann@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27 11:11:23 +01:00
GONG Ruiqi
f20fd54af4 vgacon: Add check for vc_origin address range in vgacon_scroll()
commit 864f9963ec upstream.

Our in-house Syzkaller reported the following BUG (twice), which we
believed was the same issue with [1]:

==================================================================
BUG: KASAN: slab-out-of-bounds in vcs_scr_readw+0xc2/0xd0 drivers/tty/vt/vt.c:4740
Read of size 2 at addr ffff88800f5bef60 by task syz.7.2620/12393
...
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x72/0xa0 lib/dump_stack.c:106
 print_address_description.constprop.0+0x6b/0x3d0 mm/kasan/report.c:364
 print_report+0xba/0x280 mm/kasan/report.c:475
 kasan_report+0xa9/0xe0 mm/kasan/report.c:588
 vcs_scr_readw+0xc2/0xd0 drivers/tty/vt/vt.c:4740
 vcs_write_buf_noattr drivers/tty/vt/vc_screen.c:493 [inline]
 vcs_write+0x586/0x840 drivers/tty/vt/vc_screen.c:690
 vfs_write+0x219/0x960 fs/read_write.c:584
 ksys_write+0x12e/0x260 fs/read_write.c:639
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x59/0x110 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x78/0xe2
 ...
 </TASK>

Allocated by task 5614:
 kasan_save_stack+0x20/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383
 kasan_kmalloc include/linux/kasan.h:201 [inline]
 __do_kmalloc_node mm/slab_common.c:1007 [inline]
 __kmalloc+0x62/0x140 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 vc_do_resize+0x235/0xf40 drivers/tty/vt/vt.c:1193
 vgacon_adjust_height+0x2d4/0x350 drivers/video/console/vgacon.c:1007
 vgacon_font_set+0x1f7/0x240 drivers/video/console/vgacon.c:1031
 con_font_set drivers/tty/vt/vt.c:4628 [inline]
 con_font_op+0x4da/0xa20 drivers/tty/vt/vt.c:4675
 vt_k_ioctl+0xa10/0xb30 drivers/tty/vt/vt_ioctl.c:474
 vt_ioctl+0x14c/0x1870 drivers/tty/vt/vt_ioctl.c:752
 tty_ioctl+0x655/0x1510 drivers/tty/tty_io.c:2779
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0x12d/0x190 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x59/0x110 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x78/0xe2

Last potentially related work creation:
 kasan_save_stack+0x20/0x40 mm/kasan/common.c:45
 __kasan_record_aux_stack+0x94/0xa0 mm/kasan/generic.c:492
 __call_rcu_common.constprop.0+0xc3/0xa10 kernel/rcu/tree.c:2713
 netlink_release+0x620/0xc20 net/netlink/af_netlink.c:802
 __sock_release+0xb5/0x270 net/socket.c:663
 sock_close+0x1e/0x30 net/socket.c:1425
 __fput+0x408/0xab0 fs/file_table.c:384
 __fput_sync+0x4c/0x60 fs/file_table.c:465
 __do_sys_close fs/open.c:1580 [inline]
 __se_sys_close+0x68/0xd0 fs/open.c:1565
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x59/0x110 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x78/0xe2

Second to last potentially related work creation:
 kasan_save_stack+0x20/0x40 mm/kasan/common.c:45
 __kasan_record_aux_stack+0x94/0xa0 mm/kasan/generic.c:492
 __call_rcu_common.constprop.0+0xc3/0xa10 kernel/rcu/tree.c:2713
 netlink_release+0x620/0xc20 net/netlink/af_netlink.c:802
 __sock_release+0xb5/0x270 net/socket.c:663
 sock_close+0x1e/0x30 net/socket.c:1425
 __fput+0x408/0xab0 fs/file_table.c:384
 task_work_run+0x154/0x240 kernel/task_work.c:239
 exit_task_work include/linux/task_work.h:45 [inline]
 do_exit+0x8e5/0x1320 kernel/exit.c:874
 do_group_exit+0xcd/0x280 kernel/exit.c:1023
 get_signal+0x1675/0x1850 kernel/signal.c:2905
 arch_do_signal_or_restart+0x80/0x3b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x1b3/0x1e0 kernel/entry/common.c:218
 do_syscall_64+0x66/0x110 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x78/0xe2

The buggy address belongs to the object at ffff88800f5be000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 2656 bytes to the right of
 allocated 1280-byte region [ffff88800f5be000, ffff88800f5be500)

...

Memory state around the buggy address:
 ffff88800f5bee00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88800f5bee80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88800f5bef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                       ^
 ffff88800f5bef80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88800f5bf000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

By analyzing the vmcore, we found that vc->vc_origin was somehow placed
one line prior to vc->vc_screenbuf when vc was in KD_TEXT mode, and
further writings to /dev/vcs caused out-of-bounds reads (and writes
right after) in vcs_write_buf_noattr().

Our further experiments show that in most cases, vc->vc_origin equals to
vga_vram_base when the console is in KD_TEXT mode, and it's around
vc->vc_screenbuf for the KD_GRAPHICS mode. But via triggerring a
TIOCL_SETVESABLANK ioctl beforehand, we can make vc->vc_origin be around
vc->vc_screenbuf while the console is in KD_TEXT mode, and then by
writing the special 'ESC M' control sequence to the tty certain times
(depends on the value of `vc->state.y - vc->vc_top`), we can eventually
move vc->vc_origin prior to vc->vc_screenbuf. Here's the PoC, tested on
QEMU:

```
int main() {
	const int RI_NUM = 10; // should be greater than `vc->state.y - vc->vc_top`
	int tty_fd, vcs_fd;
	const char *tty_path = "/dev/tty0";
	const char *vcs_path = "/dev/vcs";
	const char escape_seq[] = "\x1bM";  // ESC + M
	const char trigger_seq[] = "Let's trigger an OOB write.";
	struct vt_sizes vt_size = { 70, 2 };
	int blank = TIOCL_BLANKSCREEN;

	tty_fd = open(tty_path, O_RDWR);

	char vesa_mode[] = { TIOCL_SETVESABLANK, 1 };
	ioctl(tty_fd, TIOCLINUX, vesa_mode);

	ioctl(tty_fd, TIOCLINUX, &blank);
	ioctl(tty_fd, VT_RESIZE, &vt_size);

	for (int i = 0; i < RI_NUM; ++i)
		write(tty_fd, escape_seq, sizeof(escape_seq) - 1);

	vcs_fd = open(vcs_path, O_RDWR);
	write(vcs_fd, trigger_seq, sizeof(trigger_seq));

	close(vcs_fd);
	close(tty_fd);
	return 0;
}
```

To solve this problem, add an address range validation check in
vgacon_scroll(), ensuring vc->vc_origin never precedes vc_screenbuf.

Reported-by: syzbot+9c09fda97a1a65ea859b@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=9c09fda97a1a65ea859b [1]
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Co-developed-by: Yi Yang <yiyang13@huawei.com>
Signed-off-by: Yi Yang <yiyang13@huawei.com>
Signed-off-by: GONG Ruiqi <gongruiqi1@huawei.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27 11:11:21 +01:00
Murad Masimov
b3071bb463 fbdev: Fix fb_set_var to prevent null-ptr-deref in fb_videomode_to_var
commit 05f6e18387 upstream.

If fb_add_videomode() in fb_set_var() fails to allocate memory for
fb_videomode, later it may lead to a null-ptr dereference in
fb_videomode_to_var(), as the fb_info is registered while not having the
mode in modelist that is expected to be there, i.e. the one that is
described in fb_info->var.

================================================================
general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 PID: 30371 Comm: syz-executor.1 Not tainted 5.10.226-syzkaller #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:fb_videomode_to_var+0x24/0x610 drivers/video/fbdev/core/modedb.c:901
Call Trace:
 display_to_var+0x3a/0x7c0 drivers/video/fbdev/core/fbcon.c:929
 fbcon_resize+0x3e2/0x8f0 drivers/video/fbdev/core/fbcon.c:2071
 resize_screen drivers/tty/vt/vt.c:1176 [inline]
 vc_do_resize+0x53a/0x1170 drivers/tty/vt/vt.c:1263
 fbcon_modechanged+0x3ac/0x6e0 drivers/video/fbdev/core/fbcon.c:2720
 fbcon_update_vcs+0x43/0x60 drivers/video/fbdev/core/fbcon.c:2776
 do_fb_ioctl+0x6d2/0x740 drivers/video/fbdev/core/fbmem.c:1128
 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1203
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x19a/0x210 fs/ioctl.c:739
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x67/0xd1
================================================================

The reason is that fb_info->var is being modified in fb_set_var(), and
then fb_videomode_to_var() is called. If it fails to add the mode to
fb_info->modelist, fb_set_var() returns error, but does not restore the
old value of fb_info->var. Restore fb_info->var on failure the same way
it is done earlier in the function.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Murad Masimov <m.masimov@mt-integration.ru>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27 11:11:21 +01:00
Murad Masimov
3f2098f4fb fbdev: Fix do_register_framebuffer to prevent null-ptr-deref in fb_videomode_to_var
commit 17186f1f90 upstream.

If fb_add_videomode() in do_register_framebuffer() fails to allocate
memory for fb_videomode, it will later lead to a null-ptr dereference in
fb_videomode_to_var(), as the fb_info is registered while not having the
mode in modelist that is expected to be there, i.e. the one that is
described in fb_info->var.

================================================================
general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 PID: 30371 Comm: syz-executor.1 Not tainted 5.10.226-syzkaller #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:fb_videomode_to_var+0x24/0x610 drivers/video/fbdev/core/modedb.c:901
Call Trace:
 display_to_var+0x3a/0x7c0 drivers/video/fbdev/core/fbcon.c:929
 fbcon_resize+0x3e2/0x8f0 drivers/video/fbdev/core/fbcon.c:2071
 resize_screen drivers/tty/vt/vt.c:1176 [inline]
 vc_do_resize+0x53a/0x1170 drivers/tty/vt/vt.c:1263
 fbcon_modechanged+0x3ac/0x6e0 drivers/video/fbdev/core/fbcon.c:2720
 fbcon_update_vcs+0x43/0x60 drivers/video/fbdev/core/fbcon.c:2776
 do_fb_ioctl+0x6d2/0x740 drivers/video/fbdev/core/fbmem.c:1128
 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1203
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x19a/0x210 fs/ioctl.c:739
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x67/0xd1
================================================================

Even though fbcon_init() checks beforehand if fb_match_mode() in
var_to_display() fails, it can not prevent the panic because fbcon_init()
does not return error code. Considering this and the comment in the code
about fb_match_mode() returning NULL - "This should not happen" - it is
better to prevent registering the fb_info if its mode was not set
successfully. Also move fb_add_videomode() closer to the beginning of
do_register_framebuffer() to avoid having to do the cleanup on fail.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Murad Masimov <m.masimov@mt-integration.ru>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27 11:11:21 +01:00
Henry Martin
1be2000b70 backlight: pm8941: Add NULL check in wled_configure()
[ Upstream commit e12d3e1624 ]

devm_kasprintf() returns NULL when memory allocation fails. Currently,
wled_configure() does not check for this case, which results in a NULL
pointer dereference.

Add NULL check after devm_kasprintf() to prevent this issue.

Fixes: f86b77583d ("backlight: pm8941: Convert to using %pOFn instead of device_node.name")
Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org>
Link: https://lore.kernel.org/r/20250401091647.22784-1-bsdhenrymartin@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-19 15:32:04 +02:00
Sergey Shtylyov
b235393b9f fbdev: core: fbcvt: avoid division by 0 in fb_cvt_hperiod()
[ Upstream commit 3f6dae09fc ]

In fb_find_mode_cvt(), iff mode->refresh somehow happens to be 0x80000000,
cvt.f_refresh will become 0 when multiplying it by 2 due to overflow. It's
then passed to fb_cvt_hperiod(), where it's used as a divider -- division
by 0 will result in kernel oops. Add a sanity check for cvt.f_refresh to
avoid such overflow...

Found by Linux Verification Center (linuxtesting.org) with the Svace static
analysis tool.

Fixes: 96fe6a2109 ("[PATCH] fbdev: Add VESA Coordinated Video Timings (CVT) support")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-19 15:32:03 +02:00
Zsolt Kajtar
ff968e486e fbdev: core: tileblit: Implement missing margin clearing for tileblit
[ Upstream commit 76d3ca8998 ]

I was wondering why there's garbage at the bottom of the screen when
tile blitting is used with an odd mode like 1080, 600 or 200. Sure there's
only space for half a tile but the same area is clean when the buffer
is bitmap.

Then later I found that it's supposed to be cleaned but that's not
implemented. So I took what's in bitblit and adapted it for tileblit.

This implementation was tested for both the horizontal and vertical case,
and now does the same as what's done for bitmap buffers.

If anyone is interested to reproduce the problem then I could bet that'd
be on a S3 or Ark. Just set up a mode with an odd line count and make
sure that the virtual size covers the complete tile at the bottom. E.g.
for 600 lines that's 608 virtual lines for a 16 tall tile. Then the
bottom area should be cleaned.

For the right side it's more difficult as there the drivers won't let an
odd size happen, unless the code is modified. But once it reports back a
few pixel columns short then fbcon won't use the last column. With the
patch that column is now clean.

Btw. the virtual size should be rounded up by the driver for both axes
(not only the horizontal) so that it's dividable by the tile size.
That's a driver bug but correcting it is not in scope for this patch.

Implement missing margin clearing for tileblit

Signed-off-by: Zsolt Kajtar <soci@c64.rulez.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-29 11:02:05 +02:00
Zsolt Kajtar
8c912c0a68 fbcon: Use correct erase colour for clearing in fbcon
[ Upstream commit 892c788d73 ]

The erase colour calculation for fbcon clearing should use get_color instead
of attr_col_ec, like everything else. The latter is similar but is not correct.
For example it's missing the depth dependent remapping and doesn't care about
blanking.

The problem can be reproduced by setting up the background colour to grey
(vt.color=0x70) and having an fbcon console set to 2bpp (4 shades of gray).
Now the background attribute should be 1 (dark gray) on the console.

If the screen is scrolled when pressing enter in a shell prompt at the bottom
line then the new line is cleared using colour 7 instead of 1. That's not
something fillrect likes (at 2bbp it expect 0-3) so the result is interesting.

This patch switches to get_color with vc_video_erase_char to determine the
erase colour from attr_col_ec. That makes the latter function redundant as
no other users were left.

Use correct erase colour for clearing in fbcon

Signed-off-by: Zsolt Kajtar <soci@c64.rulez.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-29 11:02:05 +02:00
Shixiong Ou
230abe5d3f fbdev: fsl-diu-fb: add missing device_remove_file()
[ Upstream commit 86d16cd12e ]

Call device_remove_file() when driver remove.

Signed-off-by: Shixiong Ou <oushixiong@kylinos.cn>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-29 11:02:05 +02:00
Herve Codina
61a5c565fd backlight: led_bl: Hold led_access lock when calling led_sysfs_disable()
commit 276822a00d upstream.

Lockdep detects the following issue on led-backlight removal:
  [  142.315935] ------------[ cut here ]------------
  [  142.315954] WARNING: CPU: 2 PID: 292 at drivers/leds/led-core.c:455 led_sysfs_enable+0x54/0x80
  ...
  [  142.500725] Call trace:
  [  142.503176]  led_sysfs_enable+0x54/0x80 (P)
  [  142.507370]  led_bl_remove+0x80/0xa8 [led_bl]
  [  142.511742]  platform_remove+0x30/0x58
  [  142.515501]  device_remove+0x54/0x90
  ...

Indeed, led_sysfs_enable() has to be called with the led_access
lock held.

Hold the lock when calling led_sysfs_disable().

Fixes: ae232e45ac ("backlight: add led-backlight driver")
Cc: stable@vger.kernel.org
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Link: https://lore.kernel.org/r/20250122091914.309533-1-herve.codina@bootlin.com
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-20 10:15:46 +02:00
Leonid Arapov
52eafaa56f fbdev: omapfb: Add 'plane' value check
[ Upstream commit 3e411827f3 ]

Function dispc_ovl_setup is not intended to work with the value OMAP_DSS_WB
of the enum parameter plane.

The value of this parameter is initialized in dss_init_overlays and in the
current state of the code it cannot take this value so it's not a real
problem.

For the purposes of defensive coding it wouldn't be superfluous to check
the parameter value, because some functions down the call stack process
this value correctly and some not.

For example, in dispc_ovl_setup_global_alpha it may lead to buffer
overflow.

Add check for this value.

Found by Linux Verification Center (linuxtesting.org) with SVACE static
analysis tool.

Signed-off-by: Leonid Arapov <arapovl839@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-20 10:15:27 +02:00
Danila Chernetsov
238ece4937 fbdev: sm501fb: Add some geometry checks.
[ Upstream commit aee50bd88e ]

Added checks for xoffset, yoffset settings.
Incorrect settings of these parameters can lead to errors
in sm501fb_pan_ functions.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 5fc404e47b ("[PATCH] fb: SM501 framebuffer driver")
Signed-off-by: Danila Chernetsov <listdansp@mail.ru>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10 14:39:17 +02:00
Arnd Bergmann
8356f45700 mdacon: rework dependency list
[ Upstream commit 5bbcc7645f ]

mdacon has roughly the same dependencies as vgacon but expresses them
as a negative list instead of a positive list, with the only practical
difference being PowerPC/CHRP, which uses vga16fb instead of vgacon.

The CONFIG_MDA_CONSOLE description advises to only turn it on when vgacon
is also used because MDA/Hercules-only systems should be using vgacon
instead, so just change the list to enforce that directly for simplicity.

The probing was broken from 2002 to 2008, this improves on the fix
that was added then: If vgacon is a loadable module, then mdacon
cannot be built-in now, and the list of systems that support vgacon
is carried over.

Fixes: 0b9cf3aa6b ("mdacon messing up default vc's - set default to vc13-16 again")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10 14:39:17 +02:00
Arnd Bergmann
d3ea050c15 dummycon: fix default rows/cols
[ Upstream commit beefaba197 ]

dummycon fails to build on ARM/footbridge when the VGA console is
disabled, since I got the dependencies slightly wrong in a previous
patch:

drivers/video/console/dummycon.c: In function 'dummycon_init':
drivers/video/console/dummycon.c:27:25: error: 'CONFIG_DUMMY_CONSOLE_COLUMNS' undeclared (first use in this function); did you mean 'CONFIG_DUMMY_CONSOLE'?
   27 | #define DUMMY_COLUMNS   CONFIG_DUMMY_CONSOLE_COLUMNS
drivers/video/console/dummycon.c:28:25: error: 'CONFIG_DUMMY_CONSOLE_ROWS' undeclared (first use in this function); did you mean 'CONFIG_DUMMY_CONSOLE'?
   28 | #define DUMMY_ROWS      CONFIG_DUMMY_CONSOLE_ROWS

This only showed up after many thousand randconfig builds on Arm, and
doesn't matter in practice, but should still be fixed. Address it by
using the default row/columns on footbridge after all in that corner
case.

Fixes: 4293b09251 ("dummycon: limit Arm console size hack to footbridge")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202409151512.LML1slol-lkp@intel.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10 14:39:16 +02:00
Markus Elfring
9a14cacaf5 fbdev: au1100fb: Move a variable assignment behind a null pointer check
[ Upstream commit 2df2c0caae ]

The address of a data structure member was determined before
a corresponding null pointer check in the implementation of
the function “au1100fb_setmode”.

This issue was detected by using the Coccinelle software.

Fixes: 3b495f2bb7 ("Au1100 FB driver uplift for 2.6.")
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Acked-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10 14:39:16 +02:00