kernel/linux.git/drivers/video/fbdev/core, branch v4.14.217

fbcon: Fix global-out-of-bounds read in fbcon_get_font()

2020-10-14T07:51:10+00:00

commit 5af08640795b2b9a940c9266c0260455377ae262 upstream. fbcon_get_font() is reading out-of-bounds. A malicious user may resize `vc->vc_font.height` to a large value, causing fbcon_get_font() to read out of `fontdata`. fbcon_get_font() handles both built-in and user-provided fonts. Fortunately, recently we have added FONT_EXTRA_WORDS support for built-in fonts, so fix it by adding range checks using FNTSIZE(). This patch depends on patch "fbdev, newport_con: Move FONT_EXTRA_WORDS macros into linux/font.h", and patch "Fonts: Support FONT_EXTRA_WORDS macros for built-in fonts". Cc: stable@vger.kernel.org Reported-and-tested-by: syzbot+29d4ed7f3bdedf2aa2fd@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=08b8be45afea11888776f897895aef9ad1c3ecfd Signed-off-by: Peilin Ye Reviewed-by: Greg Kroah-Hartman Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/b34544687a1a09d6de630659eb7a773f4953238b.1600953813.git.yepeilin.cs@gmail.com Signed-off-by: Greg Kroah-Hartman

fbdev, newport_con: Move FONT_EXTRA_WORDS macros into linux/font.h

2020-10-14T07:51:10+00:00

commit bb0890b4cd7f8203e3aa99c6d0f062d6acdaad27 upstream. drivers/video/console/newport_con.c is borrowing FONT_EXTRA_WORDS macros from drivers/video/fbdev/core/fbcon.h. To keep things simple, move all definitions into . Since newport_con now uses four extra words, initialize the fourth word in newport_set_font() properly. Cc: stable@vger.kernel.org Signed-off-by: Peilin Ye Reviewed-by: Greg Kroah-Hartman Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/7fb8bc9b0abc676ada6b7ac0e0bd443499357267.1600953813.git.yepeilin.cs@gmail.com Signed-off-by: Greg Kroah-Hartman

fbcon: Fix user font detection test at fbcon_resize().

2020-09-23T08:46:35+00:00

[ Upstream commit ec0972adecb391a8d8650832263a4790f3bfb4df ] syzbot is reporting OOB read at fbcon_resize() [1], for commit 39b3cffb8cf31117 ("fbcon: prevent user font height or width change from causing potential out-of-bounds access") is by error using registered_fb[con2fb_map[vc->vc_num]]->fbcon_par->p->userfont (which was set to non-zero) instead of fb_display[vc->vc_num].userfont (which remains zero for that display). We could remove tricky userfont flag [2], for we can determine it by comparing address of the font data and addresses of built-in font data. But since that commit is failing to fix the original OOB read [3], this patch keeps the change minimal in case we decide to revert altogether. [1] https://syzkaller.appspot.com/bug?id=ebcbbb6576958a496500fee9cf7aa83ea00b5920 [2] https://syzkaller.appspot.com/text?tag=Patch&x=14030853900000 [3] https://syzkaller.appspot.com/bug?id=6fba8c186d97cf1011ab17660e633b1cc4e080c9 Reported-by: syzbot Signed-off-by: Tetsuo Handa Fixes: 39b3cffb8cf31117 ("fbcon: prevent user font height or width change from causing potential out-of-bounds access") Cc: George Kennedy Link: https://lore.kernel.org/r/f6e3e611-8704-1263-d163-f52c906a4f06@I-love.SAKURA.ne.jp Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

fbcon: remove now unusued 'softback_lines' cursor() argument

2020-09-23T08:46:31+00:00

commit 06a0df4d1b8b13b551668e47b11fd7629033b7df upstream. Since the softscroll code got removed, this argument is always zero and makes no sense any more. Tested-by: Yuan Ming Tested-by: Willy Tarreau Reviewed-by: Greg Kroah-Hartman Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

fbcon: remove soft scrollback code

2020-09-23T08:46:31+00:00

commit 50145474f6ef4a9c19205b173da6264a644c7489 upstream. This (and the VGA soft scrollback) turns out to have various nasty small special cases that nobody really is willing to fight. The soft scrollback code was really useful a few decades ago when you typically used the console interactively as the main way to interact with the machine, but that just isn't the case any more. So it's not worth dragging along. Tested-by: Yuan Ming Tested-by: Willy Tarreau Acked-by: Bartlomiej Zolnierkiewicz Acked-by: Daniel Vetter Reviewed-by: Greg Kroah-Hartman Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

fbcon: prevent user font height or width change from causing potential out-of-bounds access

2020-09-03T09:22:30+00:00

commit 39b3cffb8cf3111738ea993e2757ab382253d86a upstream. Add a check to fbcon_resize() to ensure that a possible change to user font height or user font width will not allow a font data out-of-bounds access. NOTE: must use original charcount in calculation as font charcount can change and cannot be used to determine the font data allocated size. Signed-off-by: George Kennedy Cc: stable Reported-by: syzbot+38a3699c7eaf165b97a6@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/1596213192-6635-1-git-send-email-george.kennedy@oracle.com Signed-off-by: Greg Kroah-Hartman

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

2020-07-29T05:42:57+00:00

commit 033724d6864245a11f8e04c066002e6ad22b3fd0 upstream. 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

fbdev: potential information leak in do_fb_ioctl()

2020-04-24T06:01:23+00:00

commit d3d19d6fc5736a798b118971935ce274f7deaa82 upstream. 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 Signed-off-by: Greg Kroah-Hartman

fbcon: fix null-ptr-deref in fbcon_switch

2020-04-13T08:34:36+00:00

commit b139f8b00db4a8ea75a4174346eafa48041aa489 upstream. 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 Signed-off-by: Greg Kroah-Hartman

fbdev: Ditch fb_edid_add_monspecs

2019-11-24T07:22:48+00:00

commit 3b8720e63f4a1fc6f422a49ecbaa3b59c86d5aaf upstream. It's dead code ever since commit 34280340b1dc74c521e636f45cd728f9abf56ee2 Author: Geert Uytterhoeven Date: Fri Dec 4 17:01:43 2015 +0100 fbdev: Remove unused SH-Mobile HDMI driver Also with this gone we can remove the cea_modes db. This entire thing is massively incomplete anyway, compared to the CEA parsing that drm_edid.c does. Acked-by: Linus Torvalds Cc: Tavis Ormandy Signed-off-by: Daniel Vetter Signed-off-by: Bartlomiej Zolnierkiewicz Link: https://patchwork.freedesktop.org/patch/msgid/20190721201956.941-1-daniel.vetter@ffwll.ch Signed-off-by: Greg Kroah-Hartman