linux/drivers/video/fbdev/core, branch v5.8

fbdev: Detect integer underflow at "struct fbcon_ops"->clear_margins.

2020-07-23T14:22:25Z

syzbot is reporting general protection fault in bitfill_aligned() [1] caused by integer underflow in bit_clear_margins(). The cause of this problem is when and how do_vc_resize() updates vc->vc_{cols,rows}. If vc_do_resize() fails (e.g. kzalloc() fails) when var.xres or var.yres is going to shrink, vc->vc_{cols,rows} will not be updated. This allows bit_clear_margins() to see info->var.xres < (vc->vc_cols * cw) or info->var.yres < (vc->vc_rows * ch). Unexpectedly large rw or bh will try to overrun the __iomem region and causes general protection fault. Also, vc_resize(vc, 0, 0) does not set vc->vc_{cols,rows} = 0 due to new_cols = (cols ? cols : vc->vc_cols); new_rows = (lines ? lines : vc->vc_rows); exception. Since cols and lines are calculated as cols = FBCON_SWAP(ops->rotate, info->var.xres, info->var.yres); rows = FBCON_SWAP(ops->rotate, info->var.yres, info->var.xres); cols /= vc->vc_font.width; rows /= vc->vc_font.height; vc_resize(vc, cols, rows); in fbcon_modechanged(), var.xres < vc->vc_font.width makes cols = 0 and var.yres < vc->vc_font.height makes rows = 0. This means that const int fd = open("/dev/fb0", O_ACCMODE); struct fb_var_screeninfo var = { }; ioctl(fd, FBIOGET_VSCREENINFO, &var); var.xres = var.yres = 1; ioctl(fd, FBIOPUT_VSCREENINFO, &var); easily reproduces integer underflow bug explained above. Of course, callers of vc_resize() are not handling vc_do_resize() failure is bad. But we can't avoid vc_resize(vc, 0, 0) which returns 0. Therefore, as a band-aid workaround, this patch checks integer underflow in "struct fbcon_ops"->clear_margins call, assuming that vc->vc_cols * vc->vc_font.width and vc->vc_rows * vc->vc_font.heigh do not cause integer overflow. [1] https://syzkaller.appspot.com/bug?id=a565882df74fa76f10d3a6fec4be31098dbb37c6 Reported-and-tested-by: syzbot Signed-off-by: Tetsuo Handa Acked-by: Daniel Vetter Cc: stable Link: https://lore.kernel.org/r/20200715015102.3814-1-penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Greg Kroah-Hartman

drm/fb-helper: Fix vt restore

2020-06-24T19:34:11Z

In the past we had a pile of hacks to orchestrate access between fbdev emulation and native kms clients. We've tried to streamline this, by always preferring the kms side above fbdev calls when a drm master exists, because drm master controls access to the display resources. Unfortunately this breaks existing userspace, specifically Xorg. When exiting Xorg first restores the console to text mode using the KDSET ioctl on the vt. This does nothing, because a drm master is still around. Then it drops the drm master status, which again does nothing, because logind is keeping additional drm fd open to be able to orchestrate vt switches. In the past this is the point where fbdev was restored, as part of the ->lastclose hook on the drm side. Now to fix this regression we don't want to go back to letting fbdev restore things whenever it feels like, or to the pile of hacks we've had before. Instead try and go with a minimal exception to make the KDSET case work again, and nothing else. This means that if userspace does a KDSET call when switching between graphical compositors, there will be some flickering with fbcon showing up for a bit. But a) that's not a regression and b) userspace can fix it by improving the vt switching dance - logind should have all the information it needs. While pondering all this I'm also wondering wheter we should have a SWITCH_MASTER ioctl to allow race-free master status handover. But that's for another day. v2: Somehow forgot to cc all the fbdev people. v3: Fix typo Alex spotted. Reviewed-by: Alex Deucher Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=208179 Cc: shlomo@fastmail.com Reported-and-Tested-by: shlomo@fastmail.com Cc: Michel Dänzer Fixes: 64914da24ea9 ("drm/fbdev-helper: don't force restores") Cc: Noralf Trønnes Cc: Thomas Zimmermann Cc: Daniel Vetter Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: David Airlie Cc: Daniel Vetter Cc: dri-devel@lists.freedesktop.org Cc: # v5.7+ Cc: Bartlomiej Zolnierkiewicz Cc: Geert Uytterhoeven Cc: Nathan Chancellor Cc: Qiujun Huang Cc: Peter Rosin Cc: linux-fbdev@vger.kernel.org Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20200624092910.3280448-1-daniel.vetter@ffwll.ch

Merge tag 'drm-misc-next-2020-04-14' of git://anongit.freedesktop.org/drm/drm-misc into drm-next

2020-04-22T00:41:35Z

drm-misc-next for 5.8: UAPI Changes: - drm: error out with EBUSY when device has existing master - drm: rework SET_MASTER and DROP_MASTER perm handling Cross-subsystem Changes: - mm: export two symbols from slub/slob - fbdev: savage: fix -Wextra build warning - video: omap2: Use scnprintf() for avoiding potential buffer overflow Core Changes: - Remove drm_pci.h - drm_pci_{alloc/free)() are now legacy - Introduce managed DRM resourcesA - Allow drivers to subclass struct drm_framebuffer - Introduce struct drm_afbc_framebuffer and helpers - fbdev: remove return value from generic fbdev setup - Introduce simple-encoder helper - vram-helpers: set fence on plane - dp_mst: ACT timeout improvements - dp_mst: Remove drm_dp_mst_has_audio() - TTM: ttm_trace_dma_{map/unmap}() cleanups - dma-buf: add flag for PCIP2P support - EDID: Various improvements - Encoder: cleanup semantics of possible_clones and possible_crtcs - VBLANK documentation updates - Writeback documentation updates Driver Changes: - Convert several drivers to i2c_new_client_device() - Drop explicit drm_mode_config_cleanup() calls from drivers - Auto-release device structures with drmm_add_final_kfree() - Init bfdev console after registering DRM device - Make various .debugfs functions return 0 unconditionally; ignore errors - video: Use scnprintf() to avoid buffer overflows - Convert drivers to simple encoders - drm/amdgpu: note that we can handle peer2peer DMA-buf - drm/amdgpu: add support for exporting VRAM using DMA-buf v3 - drm/kirin: Revert change to register connectors - drm/lima: Add optional devfreq and cooling device support - drm/lima: Various improvements wrt. task handling - drm/panel: nt39016: Support multiple modes and 50Hz - drm/panel: Support Leadtek LTK050H3146W - drm/rockchip: Add support for afbc - drm/virtio: Various cleanups - drm/hisilicon/hibmc: Enforce 128-byte stride alignment - drm/qxl: Fix notify port address of cursor ring buffer - drm/sun4i: Improvements to format handling - drm/bridge: dw-hdmi: Various improvements Signed-off-by: Dave Airlie From: Thomas Zimmermann Link: https://patchwork.freedesktop.org/patch/msgid/20200414090738.GA16827@linux-uq9g

fbcon: fix null-ptr-deref in fbcon_switch

2020-03-31T07:59:38Z

Set logo_shown to FBCON_LOGO_CANSHOW when the vc was deallocated. syzkaller report: https://lkml.org/lkml/2020/3/27/403 general protection fault, probably for non-canonical address 0xdffffc000000006c: 0000 [#1] SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000360-0x0000000000000367] RIP: 0010:fbcon_switch+0x28f/0x1740 drivers/video/fbdev/core/fbcon.c:2260 Call Trace: redraw_screen+0x2a8/0x770 drivers/tty/vt/vt.c:1008 vc_do_resize+0xfe7/0x1360 drivers/tty/vt/vt.c:1295 fbcon_init+0x1221/0x1ab0 drivers/video/fbdev/core/fbcon.c:1219 visual_init+0x305/0x5c0 drivers/tty/vt/vt.c:1062 do_bind_con_driver+0x536/0x890 drivers/tty/vt/vt.c:3542 do_take_over_console+0x453/0x5b0 drivers/tty/vt/vt.c:4122 do_fbcon_takeover+0x10b/0x210 drivers/video/fbdev/core/fbcon.c:588 fbcon_fb_registered+0x26b/0x340 drivers/video/fbdev/core/fbcon.c:3259 do_register_framebuffer drivers/video/fbdev/core/fbmem.c:1664 [inline] register_framebuffer+0x56e/0x980 drivers/video/fbdev/core/fbmem.c:1832 dlfb_usb_probe.cold+0x1743/0x1ba3 drivers/video/fbdev/udlfb.c:1735 usb_probe_interface+0x310/0x800 drivers/usb/core/driver.c:374 accessing vc_cons[logo_shown].d->vc_top causes the bug. Reported-by: syzbot+732528bae351682f1f27@syzkaller.appspotmail.com Signed-off-by: Qiujun Huang Acked-by: Sam Ravnborg Cc: stable@vger.kernel.org Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20200329085647.25133-1-hqjagain@gmail.com

fbdev: fbmon: fix -Wextra build warnings

2020-03-20T13:29:07Z

When 'DEBUG' is not defined, modify the DPRINTK() macro to use the no_printk() macro instead of using . This fixes a build warning when -Wextra is used and provides printk format checking: ../drivers/video/fbdev/core/fbmon.c:812:47: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body] ../drivers/video/fbdev/core/fbmon.c:842:24: warning: suggest braces around empty body in an ‘else’ statement [-Wempty-body] ../drivers/video/fbdev/core/fbmon.c:847:24: warning: suggest braces around empty body in an ‘else’ statement [-Wempty-body] Signed-off-by: Randy Dunlap Cc: Antonino Daplas Cc: Florian Tobias Schandinat Signed-off-by: Bartlomiej Zolnierkiewicz Link: https://patchwork.freedesktop.org/patch/msgid/20200315041002.24473-2-rdunlap@infradead.org

fbdev: remove object duplication in Makefile

2020-01-15T16:31:52Z

The objects in $(fb-objs) $(fb-y) $(fb-m) are linked to fb.ko . This line adds $(fb-y) to fb-objs, so the objects from $(fb-y) are listed twice as the dependency of the module. It works because Kbuild trims the duplicated objects from linking, but there is no good reason to have this line. Signed-off-by: Masahiro Yamada Signed-off-by: Bartlomiej Zolnierkiewicz Link: https://patchwork.freedesktop.org/patch/msgid/20200106081352.27730-1-masahiroy@kernel.org

fbmem: Adjust indentation in fb_prepare_logo and fb_blank

2020-01-15T16:31:47Z

Clang warns: ../drivers/video/fbdev/core/fbmem.c:665:3: warning: misleading indentation; statement is not part of the previous 'else' [-Wmisleading-indentation] if (fb_logo.depth > 4 && depth > 4) { ^ ../drivers/video/fbdev/core/fbmem.c:661:2: note: previous statement is here else ^ ../drivers/video/fbdev/core/fbmem.c:1075:3: warning: misleading indentation; statement is not part of the previous 'if' [-Wmisleading-indentation] return ret; ^ ../drivers/video/fbdev/core/fbmem.c:1072:2: note: previous statement is here if (!ret) ^ 2 warnings generated. This warning occurs because there are spaces before the tabs on these lines. Normalize the indentation in these functions so that it is consistent with the Linux kernel coding style and clang no longer warns. Fixes: 1692b37c99d5 ("fbdev: Fix logo if logo depth is less than framebuffer depth") Link: https://github.com/ClangBuiltLinux/linux/issues/825 Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Signed-off-by: Bartlomiej Zolnierkiewicz Link: https://patchwork.freedesktop.org/patch/msgid/20191218030025.10064-1-natechancellor@gmail.com

fbcon: Adjust indentation in set_con2fb_map

2020-01-15T16:31:46Z

Clang warns: ../drivers/video/fbdev/core/fbcon.c:915:3: warning: misleading indentation; statement is not part of the previous 'if' [-Wmisleading-indentation] return err; ^ ../drivers/video/fbdev/core/fbcon.c:912:2: note: previous statement is here if (!search_fb_in_map(info_idx)) ^ 1 warning generated. This warning occurs because there is a space before the tab on this line. This happens on several lines in this function; normalize them so that the indentation is consistent with the Linux kernel coding style and clang no longer warns. This warning was introduced before the beginning of git history so no fixes tab. Link: https://github.com/ClangBuiltLinux/linux/issues/824 Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Signed-off-by: Bartlomiej Zolnierkiewicz Link: https://patchwork.freedesktop.org/patch/msgid/20191218025337.35044-1-natechancellor@gmail.com

fbdev: potential information leak in do_fb_ioctl()

2020-01-15T16:31:39Z

The "fix" struct has a 2 byte hole after ->ywrapstep and the "fix = info->fix;" assignment doesn't necessarily clear it. It depends on the compiler. The solution is just to replace the assignment with an memcpy(). Fixes: 1f5e31d7e55a ("fbmem: don't call copy_from/to_user() with mutex held") Signed-off-by: Dan Carpenter Cc: Andrew Morton Cc: Arnd Bergmann Cc: "Eric W. Biederman" Cc: Andrea Righi Cc: Daniel Vetter Cc: Sam Ravnborg Cc: Maarten Lankhorst Cc: Daniel Thompson Cc: Peter Rosin Cc: Jani Nikula Cc: Gerd Hoffmann Signed-off-by: Bartlomiej Zolnierkiewicz Link: https://patchwork.freedesktop.org/patch/msgid/20200113100132.ixpaymordi24n3av@kili.mountain

Merge drm/drm-next into drm-misc-next

2020-01-06T09:35:33Z

Requested, and we need v5.5-rc1 backported as our current branch is still based on v5.4. Signed-off-by: Maarten Lankhorst