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-rw-r--r--arch/x86/kernel/cpu/mtrr/if.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/if.c b/arch/x86/kernel/cpu/mtrr/if.c
index f04e7252760..3c1b12d461d 100644
--- a/arch/x86/kernel/cpu/mtrr/if.c
+++ b/arch/x86/kernel/cpu/mtrr/if.c
@@ -96,17 +96,24 @@ mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos)
unsigned long long base, size;
char *ptr;
char line[LINE_SIZE];
+ int length;
size_t linelen;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- if (!len)
- return -EINVAL;
memset(line, 0, LINE_SIZE);
- if (len > LINE_SIZE)
- len = LINE_SIZE;
- if (copy_from_user(line, buf, len - 1))
+
+ length = len;
+ length--;
+
+ if (length > LINE_SIZE - 1)
+ length = LINE_SIZE - 1;
+
+ if (length < 0)
+ return -EINVAL;
+
+ if (copy_from_user(line, buf, length))
return -EFAULT;
linelen = strlen(line);