From: Nicolas Pitre nico@fluxnic.net
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
--- drivers/tty/vt/vt.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- 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_allo /* 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_allo
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; }