| From 814f00bb5c0bad30736bc423b23d5ab902c2619c Mon Sep 17 00:00:00 2001 |
| From: Nicolas Pitre <nico@fluxnic.net> |
| Date: Sat, 28 Mar 2020 22:25:11 -0400 |
| Subject: [PATCH] vt: don't use kmalloc() for the unicode screen buffer |
| |
| 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> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c |
| index 0a115e567b30..a54135f6861c 100644 |
| --- a/drivers/tty/vt/vt.c |
| +++ b/drivers/tty/vt/vt.c |
| @@ -81,6 +81,7 @@ |
| #include <linux/errno.h> |
| #include <linux/kd.h> |
| #include <linux/slab.h> |
| +#include <linux/vmalloc.h> |
| #include <linux/major.h> |
| #include <linux/mm.h> |
| #include <linux/console.h> |
| @@ -350,7 +351,7 @@ static struct uni_screen *vc_uniscr_alloc(unsigned int cols, unsigned int rows) |
| /* allocate everything in one go */ |
| memsize = cols * rows * sizeof(char32_t); |
| memsize += rows * sizeof(char32_t *); |
| - p = kmalloc(memsize, GFP_KERNEL); |
| + p = vmalloc(memsize); |
| if (!p) |
| return NULL; |
| |
| @@ -366,7 +367,7 @@ static struct uni_screen *vc_uniscr_alloc(unsigned int cols, unsigned int rows) |
| |
| static void vc_uniscr_set(struct vc_data *vc, struct uni_screen *new_uniscr) |
| { |
| - kfree(vc->vc_uni_screen); |
| + vfree(vc->vc_uni_screen); |
| vc->vc_uni_screen = new_uniscr; |
| } |
| |
| -- |
| 2.7.4 |
| |