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Commit e3f5a5f2 authored by Kay Sievers's avatar Kay Sievers Committed by Greg Kroah-Hartman
Browse files

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: default avatarMichael Neuling <mikey@neuling.org>
Signed-off-by: default avatarKay Sievers <kay@vrfy.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5c53d819

kernel/printk.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -465,7 +465,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf, 
	for (i = 0; i < msg->text_len; i++) {

	for (i = 0; i < msg->text_len; i++) {

		unsigned char c = log_text(msg)[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);

			len += sprintf(user->buf + len, "\\x%02x", c);

		else

		else

			user->buf[len++] = c;

			user->buf[len++] = c;
@@ -489,7 +489,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf, 
				continue;

				continue;

			}

			}





			if (c < ' ' || c >= 128) {

			if (c < ' ' || c >= 127 || c == '\\') {

				len += sprintf(user->buf + len, "\\x%02x", c);

				len += sprintf(user->buf + len, "\\x%02x", c);

				continue;

				continue;

			}

			}