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x86/ras/mce_amd_inj: Return early on invalid input 

Invalid inputs such as these are currently reported in dmesg as
failing:

  $> echo sweet > flags
  [  122.079139] flags_write: Invalid flags value: et

even though the 'flags' attribute has been updated correctly:

  $> cat flags
  sw

This is because userspace keeps writing the remaining buffer
until it encounters an error.

However, the input as a whole is wrong and we should not be
writing anything to the file. Therefore, correct flags_write()
to return -EINVAL immediately on bad input strings.

Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1443190851-2172-2-git-send-email-Aravind.Gopalakrishnan@amd.com
Link: http://lkml.kernel.org/r/1444641762-9437-3-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
hifive-unleashed-5.1
Aravind Gopalakrishnan 2015-10-12 11:22:38 +02:00 committed by Ingo Molnar
parent cdbcd239e2
commit 85c9306d44
1 changed files with 3 additions and 6 deletions
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9
arch/x86/ras/mce_amd_inj.c
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@ -129,12 +129,9 @@ static ssize_t flags_write(struct file *filp, const char __user *ubuf,
{
char buf[MAX_FLAG_OPT_SIZE], *__buf;
int err;
size_t ret;
if (cnt > MAX_FLAG_OPT_SIZE)
cnt = MAX_FLAG_OPT_SIZE;
ret = cnt;
return -EINVAL;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
@ -150,9 +147,9 @@ static ssize_t flags_write(struct file *filp, const char __user *ubuf,
return err;
}
*ppos += ret;
*ppos += cnt;
return ret;
return cnt;
}
static const struct file_operations flags_fops = {