From: Karel Zak <kzak@redhat.com>
Date: Wed, 16 Jun 2021 08:46:40 +0000 (+0200)
Subject: libblkid: fix and cleanup blkid_safe_string()
X-Git-Tag: v2.38-rc1~454
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=66e259c746e5dc5db7ac6b67c98b0abbc2ab2e6c;p=thirdparty%2Futil-linux.git

libblkid: fix and cleanup blkid_safe_string()

* Don't use 'size_t len' variable for utf8_encoded_valid_unichar()
  return code as it returns negative numbers on invalid utf8 sequence.

* Don't rely only on \0, but check the current position against output
  buffer size.

* Accept hex encoding like the original version.

* Use else-if to avoid unnecessary 'continue'.

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/libblkid/src/encode.c b/libblkid/src/encode.c
index 80bca176bd..8213873eea 100644
--- a/libblkid/src/encode.c
+++ b/libblkid/src/encode.c
@@ -230,30 +230,34 @@ int blkid_safe_string(const char *str, char *str_safe, size_t len)
 	if (!str || !str_safe || !len)
 		return -1;
 
-	len = strnlen(str, len);
-	__normalize_whitespace((const unsigned char *) str, len,
-			       (unsigned char *) str_safe, len + 1);
+	__normalize_whitespace(
+			(const unsigned char *) str, strnlen(str, len),
+			(unsigned char *) str_safe, len);
 
-	while (str_safe[i] != '\0') {
-		/* accept ASCII from '<space>' to '~' */
-		if (str_safe[i] > 0x20 && str_safe[i] <= 0x7E) {
+	while (i < len && str_safe[i] != '\0') {
+		int seqsz;
+
+		/* accept ASCII from ' ' to '~' */
+		if (str_safe[i] > 0x20 && str_safe[i] <= 0x7E)
 			i++;
-			continue;
-		}
+
+		/* accept hex encoding */
+		else if (str_safe[i] == '\\' && str_safe[i+1] == 'x')
+			i += 2;
+
 		/* replace whitespace */
-		if (isspace(str_safe[i])) {
-			str_safe[i] = '_';
-			i++;
-			continue;
-		}
-		len = utf8_encoded_valid_unichar(&str_safe[i]);
-		if (len >= 1) {
-			i += len;
-			continue;
-		}
+		else if (isspace(str_safe[i]))
+			str_safe[i++] = '_';
+
+		/* accept valid utf8 */
+		else if ((seqsz = utf8_encoded_valid_unichar(&str_safe[i])) >= 1)
+			i += seqsz;
+
 		/* everything else is replaced with '_' */
-		str_safe[i] = '_';
-		i++;
+		else
+			str_safe[i++] = '_';
 	}
+
+	str_safe[len - 1] = '\0';
 	return 0;
 }