Commit-ID: 85c9306d44f757d2fb3b0e3e399080a025315c7f
Gitweb: http://git.kernel.org/tip/85c9306d44f757d2fb3b0e3e399080a025315c7f
Author: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@xxxxxxx>
AuthorDate: Mon, 12 Oct 2015 11:22:38 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 12 Oct 2015 16:15:47 +0200
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@xxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1443190851-2172-2-git-send-email-Aravind.Gopalakrishnan@xxxxxxx
Link: http://lkml.kernel.org/r/1444641762-9437-3-git-send-email-bp@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/ras/mce_amd_inj.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/arch/x86/ras/mce_amd_inj.c b/arch/x86/ras/mce_amd_inj.c
index 17e35b5..4fd8bb9 100644
--- a/arch/x86/ras/mce_amd_inj.c
+++ b/arch/x86/ras/mce_amd_inj.c
@@ -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 = {
--
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