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. Reported-by: Michael Neuling <[email protected]> Signed-off-by: Kay Sievers <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
adn770 · Jul 6, 2012 · e3f5a5f · e3f5a5f
1 parent 5c53d81
commit e3f5a5f
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/kernel/printk.c b/kernel/printk.c
@@ -465,7 +465,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
 	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 *file, char __user *buf,
 				continue;
 			}
 
-			if (c < ' ' || c >= 128) {
+			if (c < ' ' || c >= 127 || c == '\\') {
 				len += sprintf(user->buf + len, "\\x%02x", c);
 				continue;
 			}