This is a note to let you know that I've just added the patch titled tty: vt: initialize unicode screen buffer to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tty-vt-initialize-unicode-screen-buffer.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From af77c56aa35325daa2bc2bed5c2ebf169be61b86 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Date: Tue, 19 Jul 2022 14:49:39 +0900 Subject: tty: vt: initialize unicode screen buffer From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> commit af77c56aa35325daa2bc2bed5c2ebf169be61b86 upstream. syzbot reports kernel infoleak at vcs_read() [1], for buffer can be read immediately after resize operation. Initialize buffer using kzalloc(). ---------- #include <fcntl.h> #include <unistd.h> #include <sys/ioctl.h> #include <linux/fb.h> int main(int argc, char *argv[]) { struct fb_var_screeninfo var = { }; const int fb_fd = open("/dev/fb0", 3); ioctl(fb_fd, FBIOGET_VSCREENINFO, &var); var.yres = 0x21; ioctl(fb_fd, FBIOPUT_VSCREENINFO, &var); return read(open("/dev/vcsu", O_RDONLY), &var, sizeof(var)) == -1; } ---------- Link: https://syzkaller.appspot.com/bug?extid=31a641689d43387f05d3 [1] Cc: stable <stable@xxxxxxxxxxxxxxx> Reported-by: syzbot <syzbot+31a641689d43387f05d3@xxxxxxxxxxxxxxxxxxxxxxxxx> Reviewed-by: Jiri Slaby <jirislaby@xxxxxxxxxx> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/4ef053cf-e796-fb5e-58b7-3ae58242a4ad@xxxxxxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/vt/vt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -344,7 +344,7 @@ static struct uni_screen *vc_uniscr_allo /* allocate everything in one go */ memsize = cols * rows * sizeof(char32_t); memsize += rows * sizeof(char32_t *); - p = vmalloc(memsize); + p = vzalloc(memsize); if (!p) return NULL; Patches currently in stable-queue which might be from penguin-kernel@xxxxxxxxxxxxxxxxxxx are queue-5.10/tty-vt-initialize-unicode-screen-buffer.patch