From d4b0bcf32b946590afd29e202d6a399b84fe6c67 Mon Sep 17 00:00:00 2001 From: David Teigland Date: Mon, 4 Feb 2013 15:31:22 -0600 Subject: [PATCH] dlm: check the write size from user Return EINVAL from write if the size is larger than allowed. Do this before allocating kernel memory for the bogus size, which could lead to OOM. Reported-by: Sasha Levin Tested-by: Jana Saout Signed-off-by: David Teigland --- fs/dlm/user.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/dlm/user.c b/fs/dlm/user.c index 7ff49852b0cb..911649a47dd5 100644 --- a/fs/dlm/user.c +++ b/fs/dlm/user.c @@ -503,11 +503,11 @@ static ssize_t device_write(struct file *file, const char __user *buf, #endif return -EINVAL; -#ifdef CONFIG_COMPAT - if (count > sizeof(struct dlm_write_request32) + DLM_RESNAME_MAXLEN) -#else + /* + * can't compare against COMPAT/dlm_write_request32 because + * we don't yet know if is64bit is zero + */ if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN) -#endif return -EINVAL; kbuf = kzalloc(count + 1, GFP_NOFS);