Re: [PATCH 0/8] Rework KERN_

Kay Sievers
2012-06-05T22:55:08Z

On Tue, 2012-06-05 at 14:28 -0700, Andrew Morton wrote:

> devkmsg_writev() does weird and wonderful things with
> facilities/levels. That function incorrectly returns "success" when
> copy_from_user() faults, btw.

Oh. Better?

Thanks,
Kay

From: Kay Sievers <kay@vrfy.org>
Subject: kmsg: /dev/kmsg - properly return possible copy_from_user() failure

Reported-By: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Kay Sievers <kay@vrfy.org
---
printk.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/printk.c b/kernel/printk.c
index 32462d2..6bdacab 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -365,8 +365,10 @@ static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv,

line = buf;
for (i = 0; i < count; i++) {
- if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len))
+ if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len)) {
+ ret = -EFAULT;
goto out;
+ }
line += iv[i].iov_len;
}