diff options
| author | Jann Horn <jannh@google.com> | 2018-07-06 23:50:03 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-07-07 18:58:41 +0200 |
| commit | 15279df6f26cf2013d713904b4a0c957ae8abb96 (patch) | |
| tree | ab9a3489acdac58d266366cb4539db6a8ca269e7 | |
| parent | 1268ed0c474a5c8f165ef386f3310521b5e00e27 (diff) | |
x86/mtrr: Don't copy out-of-bounds data in mtrr_write
Don't access the provided buffer out of bounds - this can cause a kernel
out-of-bounds read when invoked through sys_splice() or other things that
use kernel_write()/__kernel_write().
Fixes: 7f8ec5a4f01a ("x86/mtrr: Convert to use strncpy_from_user() helper")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180706215003.156702-1-jannh@google.com
| -rw-r--r-- | arch/x86/kernel/cpu/mtrr/if.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/if.c b/arch/x86/kernel/cpu/mtrr/if.c index 4021d3859499..40eee6cc4124 100644 --- a/arch/x86/kernel/cpu/mtrr/if.c +++ b/arch/x86/kernel/cpu/mtrr/if.c @@ -106,7 +106,8 @@ mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos) memset(line, 0, LINE_SIZE); - length = strncpy_from_user(line, buf, LINE_SIZE - 1); + len = min_t(size_t, len, LINE_SIZE - 1); + length = strncpy_from_user(line, buf, len); if (length < 0) return length; |