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 <mpatocka@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/selection.c b/drivers/char/selection.c
index f29fbe9..cb8ca56 100644
--- a/drivers/char/selection.c
+++ b/drivers/char/selection.c
@@ -268,7 +268,7 @@
/* 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();