kernel/linux.git/drivers/video/fbdev/core, branch v5.4.113

drivers: video: fbcon: fix NULL dereference in fbcon_cursor()

2021-04-07T12:47:44+00:00

commit 01faae5193d6190b7b3aa93dae43f514e866d652 upstream. add null-check on function pointer before dereference on ops->cursor Reported-by: syzbot+b67aaae8d3a927f68d20@syzkaller.appspotmail.com Cc: stable Signed-off-by: Du Cheng Link: https://lore.kernel.org/r/20210312081421.452405-1-ducheng2@gmail.com Signed-off-by: Greg Kroah-Hartman

fbmem: add margin check to fb_check_caps()

2020-10-29T08:58:08+00:00

[ Upstream commit a49145acfb975d921464b84fe00279f99827d816 ] A fb_ioctl() FBIOPUT_VSCREENINFO call with invalid xres setting or yres setting in struct fb_var_screeninfo will result in a KASAN: vmalloc-out-of-bounds failure in bitfill_aligned() as the margins are being cleared. The margins are cleared in chunks and if the xres setting or yres setting is a value of zero upto the chunk size, the failure will occur. Add a margin check to validate xres and yres settings. Signed-off-by: George Kennedy Reported-by: syzbot+e5fd3e65515b48c02a30@syzkaller.appspotmail.com Reviewed-by: Dan Carpenter Cc: Dhaval Giani Signed-off-by: Bartlomiej Zolnierkiewicz Link: https://patchwork.freedesktop.org/patch/msgid/1594149963-13801-1-git-send-email-george.kennedy@oracle.com Signed-off-by: Sasha Levin

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

2020-10-14T08:32:56+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

2020-10-14T08:32:56+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().

2020-09-23T10:40:41+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

2020-09-17T11:47:54+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

2020-09-17T11:47:54+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

fbmem: pull fbcon_update_vcs() out of fb_set_var()

2020-09-03T09:27:09+00:00

[ Upstream commit d88ca7e1a27eb2df056bbf37ddef62e1c73d37ea ] syzbot is reporting OOB read bug in vc_do_resize() [1] caused by memcpy() based on outdated old_{rows,row_size} values, for resize_screen() can recurse into vc_do_resize() which changes vc->vc_{cols,rows} that outdates old_{rows,row_size} values which were saved before calling resize_screen(). Daniel Vetter explained that resize_screen() should not recurse into fbcon_update_vcs() path due to FBINFO_MISC_USEREVENT being still set when calling resize_screen(). Instead of masking FBINFO_MISC_USEREVENT before calling fbcon_update_vcs(), we can remove FBINFO_MISC_USEREVENT by calling fbcon_update_vcs() only if fb_set_var() returned 0. This change assumes that it is harmless to call fbcon_update_vcs() when fb_set_var() returned 0 without reaching fb_notifier_call_chain(). [1] https://syzkaller.appspot.com/bug?id=c70c88cfd16dcf6e1d3c7f0ab8648b3144b5b25e Reported-and-tested-by: syzbot Suggested-by: Daniel Vetter Signed-off-by: Tetsuo Handa Reported-by: kernel test robot for missing #include Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/075b7e37-3278-cd7d-31ab-c5073cfa8e92@i-love.sakura.ne.jp Signed-off-by: Sasha Levin

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

2020-09-03T09:27:02+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.

2020-07-29T08:18:43+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