[PATCH] kmsg: escape the backslash character while exporting data

From: Kay Sievers
Date: Tue Jul 03 2012 - 14:14:36 EST


From: Kay Sievers <kay@xxxxxxxx>
Subject: kmsg: escape the backslash character while exporting data

Non-printable characters in the log data are hex-escaped to ensure safe
post processing. We need to escape a backslash we find in the data, to be
able to distinguish it from a backslash we add for the escaping.

Also escape the non-printable character 127.

Thanks to Miloslav Trmac for the heads up.

Signed-off-by: Kay Sievers <kay@xxxxxxxx>
---
kernel/printk.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -465,7 +465,7 @@ static ssize_t devkmsg_read(struct file
for (i = 0; i < msg->text_len; i++) {
unsigned char c = log_text(msg)[i];

- if (c < ' ' || c >= 128)
+ if (c < ' ' || c >= 127 || c == '\\')
len += sprintf(user->buf + len, "\\x%02x", c);
else
user->buf[len++] = c;
@@ -489,7 +489,7 @@ static ssize_t devkmsg_read(struct file
continue;
}

- if (c < ' ' || c >= 128) {
+ if (c < ' ' || c >= 127 || c == '\\') {
len += sprintf(user->buf + len, "\\x%02x", c);
continue;
}


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