4.4-stable patches

added patches:
	vt-disable-kd_font_op_copy.patch

diff --git a/queue-4.4/series b/queue-4.4/series
index e4bee3a821d2c6b03a1cb460f3313afa1224a355..6142a45408944f46390e24f539a41217f25dbaf1 100644 (file)
--- a/queue-4.4/series
+++ b/queue-4.4/series
@@ -74,3 +74,4 @@ x86-kexec-use-up-to-dated-screen_info-copy-to-fill-b.patch
 of-fix-reserved-memory-overlap-detection.patch
 scsi-core-don-t-start-concurrent-async-scan-on-same-.patch
 vsock-use-ns_capable_noaudit-on-socket-create.patch
+vt-disable-kd_font_op_copy.patch

diff --git a/queue-4.4/vt-disable-kd_font_op_copy.patch b/queue-4.4/vt-disable-kd_font_op_copy.patch
new file mode 100644 (file)
index 0000000..9694f1d
--- /dev/null
+++ b/queue-4.4/vt-disable-kd_font_op_copy.patch
@@ -0,0 +1,117 @@
+From 3c4e0dff2095c579b142d5a0693257f1c58b4804 Mon Sep 17 00:00:00 2001
+From: Daniel Vetter <daniel.vetter@ffwll.ch>
+Date: Sun, 8 Nov 2020 16:38:06 +0100
+Subject: vt: Disable KD_FONT_OP_COPY
+
+From: Daniel Vetter <daniel.vetter@ffwll.ch>
+
+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>
+
+---
+ drivers/tty/vt/vt.c |   24 ++----------------------
+ 1 file changed, 2 insertions(+), 22 deletions(-)
+
+--- a/drivers/tty/vt/vt.c
++++ b/drivers/tty/vt/vt.c
+@@ -4226,27 +4226,6 @@ static int con_font_default(struct vc_da
+       return rc;
+ }
+ 
+-static int con_font_copy(struct vc_data *vc, struct console_font_op *op)
+-{
+-      int con = op->height;
+-      int rc;
+-
+-
+-      console_lock();
+-      if (vc->vc_mode != KD_TEXT)
+-              rc = -EINVAL;
+-      else if (!vc->vc_sw->con_font_copy)
+-              rc = -ENOSYS;
+-      else if (con < 0 || !vc_cons_allocated(con))
+-              rc = -ENOTTY;
+-      else if (con == vc->vc_num)     /* nothing to do */
+-              rc = 0;
+-      else
+-              rc = vc->vc_sw->con_font_copy(vc, con);
+-      console_unlock();
+-      return rc;
+-}
+-
+ int con_font_op(struct vc_data *vc, struct console_font_op *op)
+ {
+       switch (op->op) {
+@@ -4257,7 +4236,8 @@ int con_font_op(struct vc_data *vc, stru
+       case KD_FONT_OP_SET_DEFAULT:
+               return con_font_default(vc, op);
+       case KD_FONT_OP_COPY:
+-              return con_font_copy(vc, op);
++              /* was buggy and never really used */
++              return -EINVAL;
+       }
+       return -ENOSYS;
+ }