From 878b8619f711280fd05845e21956434b5e588cc4 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Fri, 30 Jan 2009 15:27:14 -0500 Subject: [PATCH] Fix memory corruption in console selection Fix an off-by-two memory error in console selection. The loop below goes from sel_start to sel_end (inclusive), so it writes one more character. This one more character was added to the allocated size (+1), but it was not multiplied by an UTF-8 multiplier. This patch fixes a memory corruption when UTF-8 console is used and the user selects a few characters, all of them 3-byte in UTF-8 (for example a frame line). When memory redzones are enabled, a redzone corruption is reported. When they are not enabled, trashing of random memory occurs. Signed-off-by: Mikulas Patocka Signed-off-by: Linus Torvalds --- drivers/char/selection.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/char/selection.c b/drivers/char/selection.c index f29fbe9b8ed..cb8ca569896 100644 --- a/drivers/char/selection.c +++ b/drivers/char/selection.c @@ -268,7 +268,7 @@ int set_selection(const struct tiocl_selection __user *sel, struct tty_struct *t /* Allocate a new buffer before freeing the old one ... */ multiplier = use_unicode ? 3 : 1; /* chars can take up to 3 bytes */ - bp = kmalloc((sel_end-sel_start)/2*multiplier+1, GFP_KERNEL); + bp = kmalloc(((sel_end-sel_start)/2+1)*multiplier, GFP_KERNEL); if (!bp) { printk(KERN_WARNING "selection: kmalloc() failed\n"); clear_selection(); -- 2.20.1