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[ Upstream commit 3b0c406124719b625b1aba431659f5cdc24a982c ]
This issue happens when a userspace program does an ioctl
FBIOPUT_VSCREENINFO passing the fb_var_screeninfo struct
containing only the fields xres, yres, and bits_per_pixel
with values.
If this struct is the same as the previous ioctl, the
vc_resize() detects it and doesn't call the resize_screen(),
leaving the fb_var_screeninfo incomplete. And this leads to
the updatescrollmode() calculates a wrong value to
fbcon_display->vrows, which makes the real_y() return a
wrong value of y, and that value, eventually, causes
the imageblit to access an out-of-bound address value.
To solve this issue I made the resize_screen() be called
even if the screen does not need any resizing, so it will
"fix and fill" the fb_var_screeninfo independently.
Cc: stable <stable@vger.kernel.org> # after 5.15-rc2 is out, give it time to bake
Reported-and-tested-by: syzbot+858dc7a2f7ef07c2c219@syzkaller.appspotmail.com
Signed-off-by: Igor Matheus Andrade Torrente <igormtorrente@gmail.com>
Link: https://lore.kernel.org/r/20210628134509.15895-1-igormtorrente@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 3a2b2eb55681158d3e3ef464fbf47574cf0c517c upstream.
The Linux console's VT102 implementation already consumes OSC
("Operating System Command") sequences, probably because that's how
palette changes are transmitted.
In addition to OSC, there are three other major clases of ANSI control
strings: APC ("Application Program Command"), PM ("Privacy Message"),
and DCS ("Device Control String"). They are handled similarly to OSC in
terms of termination.
Source: vt100.net
Add three new enumerated states, one for each of these types. All three
are handled the same way right now--they simply consume input until
terminated. I hope to expand upon this firmament in the future. Add
new predicate ansi_control_string(), returning true for any of these
states. Replace explicit checks against ESosc with calls to this
function. Transition to these states appropriately from the escape
initiation (ESesc) state.
This was motivated by the following Notcurses bugs:
https://github.com/dankamongmen/notcurses/issues/2050
https://github.com/dankamongmen/notcurses/issues/1828
https://github.com/dankamongmen/notcurses/issues/2069
where standard VT sequences are not consumed by the Linux console. It's
not necessary that the Linux console *support* these sequences, but it
ought *consume* these well-specified classes of sequences.
Tested by sending a variety of escape sequences to the console, and
verifying that they still worked, or were now properly consumed.
Verified that the escapes were properly terminated at a generic level.
Verified that the Notcurses tools continued to show expected output on
the Linux console, except now without escape bleedthrough.
Link: https://lore.kernel.org/lkml/YSydL0q8iaUfkphg@schwarzgerat.orthanc/
Signed-off-by: nick black <dankamongmen@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 2287a51ba822384834dafc1c798453375d1107c7 upstream.
As per the long-suffering comment.
Reported-by: Minh Yuan <yuanmingbuaa@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ffb324e6f874121f7dce5bdae5e05d02baae7269 upstream.
syzbot is reporting OOB write at vga16fb_imageblit() [1], for
resize_screen() from ioctl(VT_RESIZE) returns 0 without checking whether
requested rows/columns fit the amount of memory reserved for the graphical
screen if current mode is KD_GRAPHICS.
----------
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/kd.h>
#include <linux/vt.h>
int main(int argc, char *argv[])
{
const int fd = open("/dev/char/4:1", O_RDWR);
struct vt_sizes vt = { 0x4100, 2 };
ioctl(fd, KDSETMODE, KD_GRAPHICS);
ioctl(fd, VT_RESIZE, &vt);
ioctl(fd, KDSETMODE, KD_TEXT);
return 0;
}
----------
Allow framebuffer drivers to return -EINVAL, by moving vc->vc_mode !=
KD_GRAPHICS check from resize_screen() to fbcon_resize().
Link: https://syzkaller.appspot.com/bug?extid=1f29e126cf461c4de3b3 [1]
Reported-by: syzbot <syzbot+1f29e126cf461c4de3b3@syzkaller.appspotmail.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Tested-by: syzbot <syzbot+1f29e126cf461c4de3b3@syzkaller.appspotmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 860dafa902595fb5f1d23bbcce1215188c3341e6 upstream.
Restore the original intent of the VT_RESIZEX ioctl's `v_clin' parameter
which is the number of pixel rows per character (cell) rather than the
height of the font used.
For framebuffer devices the two values are always the same, because the
former is inferred from the latter one. For VGA used as a true text
mode device these two parameters are independent from each other: the
number of pixel rows per character is set in the CRT controller, while
font height is in fact hardwired to 32 pixel rows and fonts of heights
below that value are handled by padding their data with blanks when
loaded to hardware for use by the character generator. One can change
the setting in the CRT controller and it will update the screen contents
accordingly regardless of the font loaded.
The `v_clin' parameter is used by the `vgacon' driver to set the height
of the character cell and then the cursor position within. Make the
parameter explicit then, by defining a new `vc_cell_height' struct
member of `vc_data', set it instead of `vc_font.height' from `v_clin' in
the VT_RESIZEX ioctl, and then use it throughout the `vgacon' driver
except where actual font data is accessed which as noted above is
independent from the CRTC setting.
This way the framebuffer console driver is free to ignore the `v_clin'
parameter as irrelevant, as it always should have, avoiding any issues
attempts to give the parameter a meaning there could have caused, such
as one that has led to commit 988d0763361b ("vt_ioctl: make VT_RESIZEX
behave like VT_RESIZE"):
"syzbot is reporting UAF/OOB read at bit_putcs()/soft_cursor() [1][2],
for vt_resizex() from ioctl(VT_RESIZEX) allows setting font height
larger than actual font height calculated by con_font_set() from
ioctl(PIO_FONT). Since fbcon_set_font() from con_font_set() allocates
minimal amount of memory based on actual font height calculated by
con_font_set(), use of vt_resizex() can cause UAF/OOB read for font
data."
The problem first appeared around Linux 2.5.66 which predates our repo
history, but the origin could be identified with the old MIPS/Linux repo
also at: <git://git.kernel.org/pub/scm/linux/kernel/git/ralf/linux.git>
as commit 9736a3546de7 ("Merge with Linux 2.5.66."), where VT_RESIZEX
code in `vt_ioctl' was updated as follows:
if (clin)
- video_font_height = clin;
+ vc->vc_font.height = clin;
making the parameter apply to framebuffer devices as well, perhaps due
to the use of "font" in the name of the original `video_font_height'
variable. Use "cell" in the new struct member then to avoid ambiguity.
References:
[1] https://syzkaller.appspot.com/bug?id=32577e96d88447ded2d3b76d71254fb855245837
[2] https://syzkaller.appspot.com/bug?id=6b8355d27b2b94fb5cedf4655e3a59162d9e48e3
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org # v2.6.12+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 211b4d42b70f1c1660feaa968dac0efc2a96ac4d upstream.
syzbot reported memory leak in tty/vt.
The problem was in VT_DISALLOCATE ioctl cmd.
After allocating unimap with PIO_UNIMAP it wasn't
freed via VT_DISALLOCATE, but vc_cons[currcons].d was
zeroed.
Reported-by: syzbot+bcc922b19ccc64240b42@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210327214443.21548-1-paskripkin@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 9777f8e60e718f7b022a94f2524f967d8def1931 ]
The constant 20 makes the font sum computation signed which can lead to
sign extensions and signed wraps. It's not much of a problem as we build
with -fno-strict-overflow. But if we ever decide not to, be ready, so
switch the constant to unsigned.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210105120239.28031-7-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 3c4e0dff2095c579b142d5a0693257f1c58b4804 upstream.
It's buggy:
On Fri, Nov 06, 2020 at 10:30:08PM +0800, Minh Yuan wrote:
> We recently discovered a slab-out-of-bounds read in fbcon in the latest
> kernel ( v5.10-rc2 for now ). The root cause of this vulnerability is that
> "fbcon_do_set_font" did not handle "vc->vc_font.data" and
> "vc->vc_font.height" correctly, and the patch
> <https://lkml.org/lkml/2020/9/27/223> for VT_RESIZEX can't handle this
> issue.
>
> Specifically, we use KD_FONT_OP_SET to set a small font.data for tty6, and
> use KD_FONT_OP_SET again to set a large font.height for tty1. After that,
> we use KD_FONT_OP_COPY to assign tty6's vc_font.data to tty1's vc_font.data
> in "fbcon_do_set_font", while tty1 retains the original larger
> height. Obviously, this will cause an out-of-bounds read, because we can
> access a smaller vc_font.data with a larger vc_font.height.
Further there was only one user ever.
- Android's loadfont, busybox and console-tools only ever use OP_GET
and OP_SET
- fbset documentation only mentions the kernel cmdline font: option,
not anything else.
- systemd used OP_COPY before release 232 published in Nov 2016
Now unfortunately the crucial report seems to have gone down with
gmane, and the commit message doesn't say much. But the pull request
hints at OP_COPY being broken
https://github.com/systemd/systemd/pull/3651
So in other words, this never worked, and the only project which
foolishly every tried to use it, realized that rather quickly too.
Instead of trying to fix security issues here on dead code by adding
missing checks, fix the entire thing by removing the functionality.
Note that systemd code using the OP_COPY function ignored the return
value, so it doesn't matter what we're doing here really - just in
case a lone server somewhere happens to be extremely unlucky and
running an affected old version of systemd. The relevant code from
font_copy_to_all_vcs() in systemd was:
/* copy font from active VT, where the font was uploaded to */
cfo.op = KD_FONT_OP_COPY;
cfo.height = vcs.v_active-1; /* tty1 == index 0 */
(void) ioctl(vcfd, KDFONTOP, &cfo);
Note this just disables the ioctl, garbage collecting the now unused
callbacks is left for -next.
v2: Tetsuo found the old mail, which allowed me to find it on another
archive. Add the link too.
Acked-by: Peilin Ye <yepeilin.cs@gmail.com>
Reported-by: Minh Yuan <yuanmingbuaa@gmail.com>
References: https://lists.freedesktop.org/archives/systemd-devel/2016-June/036935.html
References: https://github.com/systemd/systemd/pull/3651
Cc: Greg KH <greg@kroah.com>
Cc: Peilin Ye <yepeilin.cs@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://lore.kernel.org/r/20201108153806.3140315-1-daniel.vetter@ffwll.ch
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 90bfdeef83f1d6c696039b6a917190dcbbad3220 upstream.
Some of the font tty ioctl's always used the current foreground VC for
their operations. Don't do that then.
This fixes a data race on fg_console.
Side note: both Michael Ellerman and Jiri Slaby point out that all these
ioctls are deprecated, and should probably have been removed long ago,
and everything seems to be using the KDFONTOP ioctl instead.
In fact, Michael points out that it looks like busybox's loadfont
program seems to have switched over to using KDFONTOP exactly _because_
of this bug (ahem.. 12 years ago ;-).
Reported-by: Minh Yuan <yuanmingbuaa@gmail.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Jiri Slaby <jirislaby@kernel.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 82e61c3909db51d91b9d3e2071557b6435018b80 upstream.
Both read-side users of func_table/func_buf need locking. Without that,
one can easily confuse the code by repeatedly setting altering strings
like:
while (1)
for (a = 0; a < 2; a++) {
struct kbsentry kbs = {};
strcpy((char *)kbs.kb_string, a ? ".\n" : "88888\n");
ioctl(fd, KDSKBSENT, &kbs);
}
When that program runs, one can get unexpected output by holding F1
(note the unxpected period on the last line):
.
88888
.8888
So protect all accesses to 'func_table' (and func_buf) by preexisting
'func_buf_lock'.
It is easy in 'k_fn' handler as 'puts_queue' is expected not to sleep.
On the other hand, KDGKBSENT needs a local (atomic) copy of the string
because copy_to_user can sleep. Use already allocated, but unused
'kbs->kb_string' for that purpose.
Note that the program above needs at least CAP_SYS_TTY_CONFIG.
This depends on the previous patch and on the func_buf_lock lock added
in commit 46ca3f735f34 (tty/vt: fix write/write race in ioctl(KDSKBSENT)
handler) in 5.2.
Likely fixes CVE-2020-25656.
Cc: <stable@vger.kernel.org>
Reported-by: Minh Yuan <yuanmingbuaa@gmail.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20201019085517.10176-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6ca03f90527e499dd5e32d6522909e2ad390896b upstream.
Use 'strlen' of the string, add one for NUL terminator and simply do
'copy_to_user' instead of the explicit 'for' loop. This makes the
KDGKBSENT case more compact.
The only thing we need to take care about is NULL 'func_table[i]'. Use
an empty string in that case.
The original check for overflow could never trigger as the func_buf
strings are always shorter or equal to 'struct kbsentry's.
Cc: <stable@vger.kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20201019085517.10176-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit bc5269ca765057a1b762e79a1cfd267cd7bf1c46 upstream.
vc_resize() can return with an error after failure. Change VT_RESIZEX ioctl
to save struct vc_data values that are modified and restore the original
values in case of error.
Signed-off-by: George Kennedy <george.kennedy@oracle.com>
Cc: stable <stable@vger.kernel.org>
Reported-by: syzbot+38a3699c7eaf165b97a6@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/1596213192-6635-2-git-send-email-george.kennedy@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f8d1653daec02315e06d30246cff4af72e76e54e upstream.
syzbot is reporting UAF bug in set_origin() from vc_do_resize() [1], for
vc_do_resize() calls kfree(vc->vc_screenbuf) before calling set_origin().
Unfortunately, in set_origin(), vc->vc_sw->con_set_origin() might access
vc->vc_pos when scroll is involved in order to manipulate cursor, but
vc->vc_pos refers already released vc->vc_screenbuf until vc->vc_pos gets
updated based on the result of vc->vc_sw->con_set_origin().
Preserving old buffer and tolerating outdated vc members until set_origin()
completes would be easier than preventing vc->vc_sw->con_set_origin() from
accessing outdated vc members.
[1] https://syzkaller.appspot.com/bug?id=6649da2081e2ebdc65c0642c214b27fe91099db3
Reported-by: syzbot <syzbot+9116ecc1978ca3a12f43@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1596034621-4714-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ce684552a266cb1c7cc2f7e623f38567adec6653 upstream.
syzbot is reporting general protection fault in do_con_write() [1] caused
by vc->vc_screenbuf == ZERO_SIZE_PTR caused by vc->vc_screenbuf_size == 0
caused by vc->vc_cols == vc->vc_rows == vc->vc_size_row == 0 caused by
fb_set_var() from ioctl(FBIOPUT_VSCREENINFO) on /dev/fb0 , for
gotoxy(vc, 0, 0) from reset_terminal() from vc_init() from vc_allocate()
from con_install() from tty_init_dev() from tty_open() on such console
causes vc->vc_pos == 0x10000000e due to
((unsigned long) ZERO_SIZE_PTR) + -1U * 0 + (-1U << 1).
I don't think that a console with 0 column or 0 row makes sense. And it
seems that vc_do_resize() does not intend to allow resizing a console to
0 column or 0 row due to
new_cols = (cols ? cols : vc->vc_cols);
new_rows = (lines ? lines : vc->vc_rows);
exception.
Theoretically, cols and rows can be any range as long as
0 < cols * rows * 2 <= KMALLOC_MAX_SIZE is satisfied (e.g.
cols == 1048576 && rows == 2 is possible) because of
vc->vc_size_row = vc->vc_cols << 1;
vc->vc_screenbuf_size = vc->vc_rows * vc->vc_size_row;
in visual_init() and kzalloc(vc->vc_screenbuf_size) in vc_allocate().
Since we can detect cols == 0 or rows == 0 via screenbuf_size = 0 in
visual_init(), we can reject kzalloc(0). Then, vc_allocate() will return
an error, and con_write() will not be called on a console with 0 column
or 0 row.
We need to make sure that integer overflow in visual_init() won't happen.
Since vc_do_resize() restricts cols <= 32767 and rows <= 32767, applying
1 <= cols <= 32767 and 1 <= rows <= 32767 restrictions to vc_allocate()
will be practically fine.
This patch does not touch con_init(), for returning -EINVAL there
does not help when we are not returning -ENOMEM.
[1] https://syzkaller.appspot.com/bug?extid=017265e8553724e514e8
Reported-and-tested-by: syzbot <syzbot+017265e8553724e514e8@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200712111013.11881-1-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b86dab054059b970111b5516ae548efaae5b3aae upstream.
When k_ascii is invoked several times in a row there is a potential for
signed integer overflow:
UBSAN: Undefined behaviour in drivers/tty/vt/keyboard.c:888:19 signed integer overflow:
10 * 1111111111 cannot be represented in type 'int'
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.11 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xce/0x128 lib/dump_stack.c:118
ubsan_epilogue+0xe/0x30 lib/ubsan.c:154
handle_overflow+0xdc/0xf0 lib/ubsan.c:184
__ubsan_handle_mul_overflow+0x2a/0x40 lib/ubsan.c:205
k_ascii+0xbf/0xd0 drivers/tty/vt/keyboard.c:888
kbd_keycode drivers/tty/vt/keyboard.c:1477 [inline]
kbd_event+0x888/0x3be0 drivers/tty/vt/keyboard.c:1495
While it can be worked around by using check_mul_overflow()/
check_add_overflow(), it is better to introduce a separate flag to
signal that number pad is being used to compose a symbol, and
change type of the accumulator from signed to unsigned, thus
avoiding undefined behavior when it overflows.
Reported-by: Kyungtae Kim <kt0755@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200525232740.GA262061@dtor-ws
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 57d38f26d81e4275748b69372f31df545dcd9b71 ]
By directly using kfree() in different places we risk missing one if
it is switched to using vfree(), especially if the corresponding
vmalloc() is hidden away within a common abstraction.
Oh wait, that's exactly what happened here.
So let's fix this by creating a common abstraction for the free case
as well.
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Reported-by: syzbot+0bfda3ade1ee9288a1be@syzkaller.appspotmail.com
Fixes: 9a98e7a80f95 ("vt: don't use kmalloc() for the unicode screen buffer")
Cc: <stable@vger.kernel.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://lore.kernel.org/r/nycvar.YSQ.7.76.2005021043110.2671@knanqh.ubzr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 9a98e7a80f95378c9ee0c644705e3b5aa54745f1 upstream.
Even if the actual screen size is bounded in vc_do_resize(), the unicode
buffer is still a little more than twice the size of the glyph buffer
and may exceed MAX_ORDER down the kmalloc() path. This can be triggered
from user space.
Since there is no point having a physically contiguous buffer here,
let's avoid the above issue as well as reducing pressure on high order
allocations by using vmalloc() instead.
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Cc: <stable@vger.kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://lore.kernel.org/r/nycvar.YSQ.7.76.2003282214210.2671@knanqh.ubzr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 2717769e204e83e65b8819c5e2ef3e5b6639b270 upstream.
The code in vc_do_resize() bounds the memory allocation size to avoid
exceeding MAX_ORDER down the kzalloc() call chain and generating a
runtime warning triggerable from user space. However, not only is it
unwise to use a literal value here, but MAX_ORDER may also be
configurable based on CONFIG_FORCE_MAX_ZONEORDER.
Let's use KMALLOC_MAX_SIZE instead.
Note that prior commit bb1107f7c605 ("mm, slab: make sure that
KMALLOC_MAX_SIZE will fit into MAX_ORDER") the KMALLOC_MAX_SIZE value
could not be relied upon.
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Cc: <stable@vger.kernel.org> # v4.10+
Link: https://lore.kernel.org/r/nycvar.YSQ.7.76.2003281702410.2671@knanqh.ubzr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 7cf64b18b0b96e751178b8d0505d8466ff5a448f upstream.
vt_in_use() dereferences console_driver->ttys[i] without proper locking.
This is broken because the tty can be closed and freed concurrently.
We could fix this by using 'READ_ONCE(console_driver->ttys[i]) != NULL'
and skipping the check of tty_struct::count. But, looking at
console_driver->ttys[i] isn't really appropriate anyway because even if
it is NULL the tty can still be in the process of being closed.
Instead, fix it by making vt_in_use() require console_lock() and check
whether the vt is allocated and has port refcount > 1. This works since
following the patch "vt: vt_ioctl: fix VT_DISALLOCATE freeing in-use
virtual console" the port refcount is incremented while the vt is open.
Reproducer (very unreliable, but it worked for me after a few minutes):
#include <fcntl.h>
#include <linux/vt.h>
int main()
{
int fd, nproc;
struct vt_stat state;
char ttyname[16];
fd = open("/dev/tty10", O_RDONLY);
for (nproc = 1; nproc < 8; nproc *= 2)
fork();
for (;;) {
sprintf(ttyname, "/dev/tty%d", rand() % 8);
close(open(ttyname, O_RDONLY));
ioctl(fd, VT_GETSTATE, &state);
}
}
KASAN report:
BUG: KASAN: use-after-free in vt_in_use drivers/tty/vt/vt_ioctl.c:48 [inline]
BUG: KASAN: use-after-free in vt_ioctl+0x1ad3/0x1d70 drivers/tty/vt/vt_ioctl.c:657
Read of size 4 at addr ffff888065722468 by task syz-vt2/132
CPU: 0 PID: 132 Comm: syz-vt2 Not tainted 5.6.0-rc5-00130-g089b6d3654916 #13
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20191223_100556-anatol 04/01/2014
Call Trace:
[...]
vt_in_use drivers/tty/vt/vt_ioctl.c:48 [inline]
vt_ioctl+0x1ad3/0x1d70 drivers/tty/vt/vt_ioctl.c:657
tty_ioctl+0x9db/0x11b0 drivers/tty/tty_io.c:2660
[...]
Allocated by task 136:
[...]
kzalloc include/linux/slab.h:669 [inline]
alloc_tty_struct+0x96/0x8a0 drivers/tty/tty_io.c:2982
tty_init_dev+0x23/0x350 drivers/tty/tty_io.c:1334
tty_open_by_driver drivers/tty/tty_io.c:1987 [inline]
tty_open+0x3ca/0xb30 drivers/tty/tty_io.c:2035
[...]
Freed by task 41:
[...]
kfree+0xbf/0x200 mm/slab.c:3757
free_tty_struct+0x8d/0xb0 drivers/tty/tty_io.c:177
release_one_tty+0x22d/0x2f0 drivers/tty/tty_io.c:1468
process_one_work+0x7f1/0x14b0 kernel/workqueue.c:2264
worker_thread+0x8b/0xc80 kernel/workqueue.c:2410
[...]
Fixes: 4001d7b7fc27 ("vt: push down the tty lock so we can see what is left to tackle")
Cc: <stable@vger.kernel.org> # v3.4+
Acked-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20200322034305.210082-3-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
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commit ca4463bf8438b403596edd0ec961ca0d4fbe0220 upstream.
The VT_DISALLOCATE ioctl can free a virtual console while tty_release()
is still running, causing a use-after-free in con_shutdown(). This
occurs because VT_DISALLOCATE considers a virtual console's
'struct vc_data' to be unused as soon as the corresponding tty's
refcount hits 0. But actually it may be still being closed.
Fix this by making vc_data be reference-counted via the embedded
'struct tty_port'. A newly allocated virtual console has refcount 1.
Opening it for the first time increments the refcount to 2. Closing it
for the last time decrements the refcount (in tty_operations::cleanup()
so that it happens late enough), as does VT_DISALLOCATE.
Reproducer:
#include <fcntl.h>
#include <linux/vt.h>
#include <sys/ioctl.h>
#include <unistd.h>
int main()
{
if (fork()) {
for (;;)
close(open("/dev/tty5", O_RDWR));
} else {
int fd = open("/dev/tty10", O_RDWR);
for (;;)
ioctl(fd, VT_DISALLOCATE, 5);
}
}
KASAN report:
BUG: KASAN: use-after-free in con_shutdown+0x76/0x80 drivers/tty/vt/vt.c:3278
Write of size 8 at addr ffff88806a4ec108 by task syz_vt/129
CPU: 0 PID: 129 Comm: syz_vt Not tainted 5.6.0-rc2 #11
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20191223_100556-anatol 04/01/2014
Call Trace:
[...]
con_shutdown+0x76/0x80 drivers/tty/vt/vt.c:3278
release_tty+0xa8/0x410 drivers/tty/tty_io.c:1514
tty_release_struct+0x34/0x50 drivers/tty/tty_io.c:1629
tty_release+0x984/0xed0 drivers/tty/tty_io.c:1789
[...]
Allocated by task 129:
[...]
kzalloc include/linux/slab.h:669 [inline]
vc_allocate drivers/tty/vt/vt.c:1085 [inline]
vc_allocate+0x1ac/0x680 drivers/tty/vt/vt.c:1066
con_install+0x4d/0x3f0 drivers/tty/vt/vt.c:3229
tty_driver_install_tty drivers/tty/tty_io.c:1228 [inline]
tty_init_dev+0x94/0x350 drivers/tty/tty_io.c:1341
tty_open_by_driver drivers/tty/tty_io.c:1987 [inline]
tty_open+0x3ca/0xb30 drivers/tty/tty_io.c:2035
[...]
Freed by task 130:
[...]
kfree+0xbf/0x1e0 mm/slab.c:3757
vt_disallocate drivers/tty/vt/vt_ioctl.c:300 [inline]
vt_ioctl+0x16dc/0x1e30 drivers/tty/vt/vt_ioctl.c:818
tty_ioctl+0x9db/0x11b0 drivers/tty/tty_io.c:2660
[...]
Fixes: 4001d7b7fc27 ("vt: push down the tty lock so we can see what is left to tackle")
Cc: <stable@vger.kernel.org> # v3.4+
Reported-by: syzbot+522643ab5729b0421998@syzkaller.appspotmail.com
Acked-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20200322034305.210082-2-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
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commit 1aa6e058dd6cd04471b1f21298270014daf48ac9 upstream.
The vc_cons_allocated() checks in vt_ioctl() and vt_compat_ioctl() are
unnecessary because they can only be reached by calling ioctl() on an
open tty, which implies the corresponding virtual console is allocated.
And even if the virtual console *could* be freed concurrently, then
these checks would be broken since they aren't done under console_lock,
and the vc_data is dereferenced before them anyway.
So, remove these unneeded checks to avoid confusion.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20200224080326.295046-1-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f400991bf872debffb01c46da882dc97d7e3248e upstream.
vt_dont_switch is pure boolean, no need for whole char.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-6-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e587e8f17433ddb26954f0edf5b2f95c42155ae9 upstream.
These two were macros. Switch them to static inlines, so that it's more
understandable what they are doing.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit dce05aa6eec977f1472abed95ccd71276b9a3864 upstream.
Avoid global variables (namely sel_cons) by introducing vc_is_sel. It
checks whether the parameter is the current selection console. This will
help putting sel_cons to a struct later.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
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commit e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2 upstream.
sel_lock cannot nest in the console lock. Thanks to syzkaller, the
kernel states firmly:
> WARNING: possible circular locking dependency detected
> 5.6.0-rc3-syzkaller #0 Not tainted
> ------------------------------------------------------
> syz-executor.4/20336 is trying to acquire lock:
> ffff8880a2e952a0 (&tty->termios_rwsem){++++}, at: tty_unthrottle+0x22/0x100 drivers/tty/tty_ioctl.c:136
>
> but task is already holding lock:
> ffffffff89462e70 (sel_lock){+.+.}, at: paste_selection+0x118/0x470 drivers/tty/vt/selection.c:374
>
> which lock already depends on the new lock.
>
> the existing dependency chain (in reverse order) is:
>
> -> #2 (sel_lock){+.+.}:
> mutex_lock_nested+0x1b/0x30 kernel/locking/mutex.c:1118
> set_selection_kernel+0x3b8/0x18a0 drivers/tty/vt/selection.c:217
> set_selection_user+0x63/0x80 drivers/tty/vt/selection.c:181
> tioclinux+0x103/0x530 drivers/tty/vt/vt.c:3050
> vt_ioctl+0x3f1/0x3a30 drivers/tty/vt/vt_ioctl.c:364
This is ioctl(TIOCL_SETSEL).
Locks held on the path: console_lock -> sel_lock
> -> #1 (console_lock){+.+.}:
> console_lock+0x46/0x70 kernel/printk/printk.c:2289
> con_flush_chars+0x50/0x650 drivers/tty/vt/vt.c:3223
> n_tty_write+0xeae/0x1200 drivers/tty/n_tty.c:2350
> do_tty_write drivers/tty/tty_io.c:962 [inline]
> tty_write+0x5a1/0x950 drivers/tty/tty_io.c:1046
This is write().
Locks held on the path: termios_rwsem -> console_lock
> -> #0 (&tty->termios_rwsem){++++}:
> down_write+0x57/0x140 kernel/locking/rwsem.c:1534
> tty_unthrottle+0x22/0x100 drivers/tty/tty_ioctl.c:136
> mkiss_receive_buf+0x12aa/0x1340 drivers/net/hamradio/mkiss.c:902
> tty_ldisc_receive_buf+0x12f/0x170 drivers/tty/tty_buffer.c:465
> paste_selection+0x346/0x470 drivers/tty/vt/selection.c:389
> tioclinux+0x121/0x530 drivers/tty/vt/vt.c:3055
> vt_ioctl+0x3f1/0x3a30 drivers/tty/vt/vt_ioctl.c:364
This is ioctl(TIOCL_PASTESEL).
Locks held on the path: sel_lock -> termios_rwsem
> other info that might help us debug this:
>
> Chain exists of:
> &tty->termios_rwsem --> console_lock --> sel_lock
Clearly. From the above, we have:
console_lock -> sel_lock
sel_lock -> termios_rwsem
termios_rwsem -> console_lock
Fix this by reversing the console_lock -> sel_lock dependency in
ioctl(TIOCL_SETSEL). First, lock sel_lock, then console_lock.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: syzbot+26183d9746e62da329b8@syzkaller.appspotmail.com
Fixes: 07e6124a1a46 ("vt: selection, close sel_buffer race")
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200228115406.5735-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 4b70dd57a15d2f4685ac6e38056bad93e81e982f upstream.
We need to nest the console lock in sel_lock, so we have to push it down
a bit. Fortunately, the callers of set_selection_* just lock the console
lock around the function call. So moving it down is easy.
In the next patch, we switch the order.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Fixes: 07e6124a1a46 ("vt: selection, close sel_buffer race")
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200228115406.5735-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 07e6124a1a46b4b5a9b3cacc0c306b50da87abf5 upstream.
syzkaller reported this UAF:
BUG: KASAN: use-after-free in n_tty_receive_buf_common+0x2481/0x2940 drivers/tty/n_tty.c:1741
Read of size 1 at addr ffff8880089e40e9 by task syz-executor.1/13184
CPU: 0 PID: 13184 Comm: syz-executor.1 Not tainted 5.4.7 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
...
kasan_report+0xe/0x20 mm/kasan/common.c:634
n_tty_receive_buf_common+0x2481/0x2940 drivers/tty/n_tty.c:1741
tty_ldisc_receive_buf+0xac/0x190 drivers/tty/tty_buffer.c:461
paste_selection+0x297/0x400 drivers/tty/vt/selection.c:372
tioclinux+0x20d/0x4e0 drivers/tty/vt/vt.c:3044
vt_ioctl+0x1bcf/0x28d0 drivers/tty/vt/vt_ioctl.c:364
tty_ioctl+0x525/0x15a0 drivers/tty/tty_io.c:2657
vfs_ioctl fs/ioctl.c:47 [inline]
It is due to a race between parallel paste_selection (TIOCL_PASTESEL)
and set_selection_user (TIOCL_SETSEL) invocations. One uses sel_buffer,
while the other frees it and reallocates a new one for another
selection. Add a mutex to close this race.
The mutex takes care properly of sel_buffer and sel_buffer_lth only. The
other selection global variables (like sel_start, sel_end, and sel_cons)
are protected only in set_selection_user. The other functions need quite
some more work to close the races of the variables there. This is going
to happen later.
This likely fixes (I am unsure as there is no reproducer provided) bug
206361 too. It was marked as CVE-2020-8648.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: syzbot+59997e8d5cbdc486e6f6@syzkaller.appspotmail.com
References: https://bugzilla.kernel.org/show_bug.cgi?id=206361
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200210081131.23572-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6cd1ed50efd88261298577cd92a14f2768eddeeb upstream.
We need to make sure vc_cons[i].d is not NULL after grabbing
console_lock(), or risk a crash.
general protection fault, probably for non-canonical address 0xdffffc0000000068: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000340-0x0000000000000347]
CPU: 1 PID: 19462 Comm: syz-executor.5 Not tainted 5.5.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:vt_ioctl+0x1f96/0x26d0 drivers/tty/vt/vt_ioctl.c:883
Code: 74 41 e8 bd a6 84 fd 48 89 d8 48 c1 e8 03 42 80 3c 28 00 0f 85 e4 04 00 00 48 8b 03 48 8d b8 40 03 00 00 48 89 fa 48 c1 ea 03 <42> 0f b6 14 2a 84 d2 74 09 80 fa 03 0f 8e b1 05 00 00 44 89 b8 40
RSP: 0018:ffffc900086d7bb0 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffffffff8c34ee88 RCX: ffffc9001415c000
RDX: 0000000000000068 RSI: ffffffff83f0e6e3 RDI: 0000000000000340
RBP: ffffc900086d7cd0 R08: ffff888054ce0100 R09: fffffbfff16a2f6d
R10: ffff888054ce0998 R11: ffff888054ce0100 R12: 000000000000001d
R13: dffffc0000000000 R14: 1ffff920010daf79 R15: 000000000000ff7f
FS: 00007f7d13c12700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd477e3c38 CR3: 0000000095d0a000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
tty_ioctl+0xa37/0x14f0 drivers/tty/tty_io.c:2660
vfs_ioctl fs/ioctl.c:47 [inline]
ksys_ioctl+0x123/0x180 fs/ioctl.c:763
__do_sys_ioctl fs/ioctl.c:772 [inline]
__se_sys_ioctl fs/ioctl.c:770 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:770
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45b399
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f7d13c11c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7d13c126d4 RCX: 000000000045b399
RDX: 0000000020000080 RSI: 000000000000560a RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000666 R14: 00000000004c7f04 R15: 000000000075bf2c
Modules linked in:
---[ end trace 80970faf7a67eb77 ]---
RIP: 0010:vt_ioctl+0x1f96/0x26d0 drivers/tty/vt/vt_ioctl.c:883
Code: 74 41 e8 bd a6 84 fd 48 89 d8 48 c1 e8 03 42 80 3c 28 00 0f 85 e4 04 00 00 48 8b 03 48 8d b8 40 03 00 00 48 89 fa 48 c1 ea 03 <42> 0f b6 14 2a 84 d2 74 09 80 fa 03 0f 8e b1 05 00 00 44 89 b8 40
RSP: 0018:ffffc900086d7bb0 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffffffff8c34ee88 RCX: ffffc9001415c000
RDX: 0000000000000068 RSI: ffffffff83f0e6e3 RDI: 0000000000000340
RBP: ffffc900086d7cd0 R08: ffff888054ce0100 R09: fffffbfff16a2f6d
R10: ffff888054ce0998 R11: ffff888054ce0100 R12: 000000000000001d
R13: dffffc0000000000 R14: 1ffff920010daf79 R15: 000000000000ff7f
FS: 00007f7d13c12700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd477e3c38 CR3: 0000000095d0a000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: stable <stable@vger.kernel.org>
Reported-by: syzbot <syzkaller@googlegroups.com>
Link: https://lore.kernel.org/r/20200210190721.200418-1-edumazet@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 687bff0cd08f790d540cfb7b2349f0d876cdddec upstream.
When pasting a selection to a vt, the task is set as INTERRUPTIBLE while
waiting for a tty to unthrottle. But signals are not handled at all.
Normally, this is not a problem as tty_ldisc_receive_buf receives all
the goods and a user has no reason to interrupt the task.
There are two scenarios where this matters:
1) when the tty is throttled and a signal is sent to the process, it
spins on a CPU until the tty is unthrottled. schedule() does not
really echedule, but returns immediately, of course.
2) when the sel_buffer becomes invalid, KASAN prevents any reads from it
and the loop simply does not proceed and spins forever (causing the
tty to throttle, but the code never sleeps, the same as above). This
sometimes happens as there is a race in the sel_buffer handling code.
So add signal handling to this ioctl (TIOCL_PASTESEL) and return -EINTR
in case a signal is pending.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200210081131.23572-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3f4ef485be9d54040b695f32ec76d0f1ea50bbf3 upstream.
Commit a6dbe4427559 ("vt: perform safe console erase in the right
order") provided fixes to an earlier commit by gathering all console
scrollback flushing operations in a function of its own. This includes
the invocation of vc_sw->con_switch() as previously done through a
update_screen() call. That commit failed to carry over the
con_is_visible() conditional though, as well as cursor handling, which
caused problems when "\e[3J" was written to a background console.
One could argue for preserving the call to update_screen(). However
this does far more than we need, and it is best to remove scrollback
assumptions from it. Instead let's gather the minimum needed to actually
perform scrollback flushing properly in that one place.
While at it, let's document the vc_sw->con_switch() side effect being
relied upon.
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Reported-and-tested-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/nycvar.YSQ.7.76.2001281205560.1655@knanqh.ubzr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 0c9acb1af77a3cb8707e43f45b72c95266903cee upstream.
Commit d21b0be246bf ("vt: introduce unicode mode for /dev/vcs") guarded
against using devices containing attributes as this is not yet
implemented. It however failed to guard against writes to any devices
as this is also unimplemented.
Reported-by: Or Cohen <orcohen@paloaltonetworks.com>
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Cc: <stable@vger.kernel.org> # v4.19+
Cc: Jiri Slaby <jslaby@suse.com>
Fixes: d21b0be246bf ("vt: introduce unicode mode for /dev/vcs")
Link: https://lore.kernel.org/r/nycvar.YSQ.7.76.1911051030580.30289@knanqh.ubzr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b2b2dd71e0859436d4e05b2f61f86140250ed3f8 upstream.
Do not try to handle keycodes that are too big, otherwise we risk doing
out-of-bounds writes:
BUG: KASAN: global-out-of-bounds in clear_bit include/asm-generic/bitops-instrumented.h:56 [inline]
BUG: KASAN: global-out-of-bounds in kbd_keycode drivers/tty/vt/keyboard.c:1411 [inline]
BUG: KASAN: global-out-of-bounds in kbd_event+0xe6b/0x3790 drivers/tty/vt/keyboard.c:1495
Write of size 8 at addr ffffffff89a1b2d8 by task syz-executor108/1722
...
kbd_keycode drivers/tty/vt/keyboard.c:1411 [inline]
kbd_event+0xe6b/0x3790 drivers/tty/vt/keyboard.c:1495
input_to_handler+0x3b6/0x4c0 drivers/input/input.c:118
input_pass_values.part.0+0x2e3/0x720 drivers/input/input.c:145
input_pass_values drivers/input/input.c:949 [inline]
input_set_keycode+0x290/0x320 drivers/input/input.c:954
evdev_handle_set_keycode_v2+0xc4/0x120 drivers/input/evdev.c:882
evdev_do_ioctl drivers/input/evdev.c:1150 [inline]
In this case we were dealing with a fuzzed HID device that declared over
12K buttons, and while HID layer should not be reporting to us such big
keycodes, we should also be defensive and reject invalid data ourselves as
well.
Reported-by: syzbot+19340dff067c2d3835c0@syzkaller.appspotmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191122204220.GA129459@dtor-ws
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Not really harmful not to, but also not harm in grabbing the lock. And
this shuts up a new WARNING I introduced in commit ddde3c18b700 ("vt:
More locking checks").
Reported-by: Jens Remus <jremus@linux.ibm.com>
Cc: linux-kernel@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Martin Hostettler <textshell@uchuujin.de>
Cc: Adam Borowski <kilobyte@angband.pl>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sam Ravnborg <sam@ravnborg.org>
Fixes: ddde3c18b700 ("vt: More locking checks")
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Tested-by: Jens Remus <jremus@linux.ibm.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://lore.kernel.org/r/20190718080903.22622-1-daniel.vetter@ffwll.ch
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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