From df11f6c516cdeb98624f4189ab4e00aeeaaaafe6 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Wed, 15 Jul 2020 12:40:07 +0300 Subject: [PATCH] platform/x86: thinkpad_acpi: Revert "Use strndup_user() in dispatch_proc_write()" This reverts commit 35d13c7a05126a5a54a1ef40aff4c6984474e604. This broke procfs interface due to neglecting the fact that the strings are not coming NULL terminated. Revert the change till we will have a better clean up. Fixes: 35d13c7a0512 ("platform/x86: thinkpad_acpi: Use strndup_user() in dispatch_proc_write()") Reported-by: Hans de Goede Signed-off-by: Andy Shevchenko --- drivers/platform/x86/thinkpad_acpi.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c index ff7f0a4f2475..0f6fceda5fc0 100644 --- a/drivers/platform/x86/thinkpad_acpi.c +++ b/drivers/platform/x86/thinkpad_acpi.c @@ -885,11 +885,19 @@ static ssize_t dispatch_proc_write(struct file *file, if (!ibm || !ibm->write) return -EINVAL; + if (count > PAGE_SIZE - 1) + return -EINVAL; - kernbuf = strndup_user(userbuf, PAGE_SIZE); - if (IS_ERR(kernbuf)) - return PTR_ERR(kernbuf); + kernbuf = kmalloc(count + 1, GFP_KERNEL); + if (!kernbuf) + return -ENOMEM; + if (copy_from_user(kernbuf, userbuf, count)) { + kfree(kernbuf); + return -EFAULT; + } + + kernbuf[count] = 0; ret = ibm->write(kernbuf); if (ret == 0) ret = count;