1 files changed, 34 insertions, 4 deletions

diff --git a/source/blender/blenlib/intern/string_utf8.c b/source/blender/blenlib/intern/string_utf8.c
index 9697fcf09e9..67ff532cb6f 100644
--- a/source/blender/blenlib/intern/string_utf8.c
+++ b/source/blender/blenlib/intern/string_utf8.c
@@ -69,11 +69,11 @@ static const char trailingBytesForUTF8[256] = {
 
 int BLI_utf8_invalid_byte(const char *str, int length)
 {
-	const unsigned char *p, *pend = (unsigned char *)str + length;
+	const unsigned char *p, *pend = (const unsigned char *)str + length;
 	unsigned char c;
 	int ab;
 
-	for (p = (unsigned char *)str; p < pend; p++) {
+	for (p = (const unsigned char *)str; p < pend; p++) {
 		c = *p;
 		if (c < 128)
 			continue;
@@ -130,7 +130,7 @@ int BLI_utf8_invalid_byte(const char *str, int length)
 
 utf8_error:
 
-	return (int)((char *)p - (char *)str) - 1;
+	return (int)((const char *)p - (const char *)str) - 1;
 }
 
 int BLI_utf8_invalid_strip(char *str, int length)
@@ -209,6 +209,22 @@ char *BLI_strncpy_utf8(char *__restrict dst, const char *__restrict src, size_t
 	return r_dst;
 }
 
+size_t BLI_strncpy_utf8_rlen(char *__restrict dst, const char *__restrict src, size_t maxncpy)
+{
+	char *r_dst = dst;
+
+	BLI_assert(maxncpy != 0);
+
+#ifdef DEBUG_STRSIZE
+	memset(dst, 0xff, sizeof(*dst) * maxncpy);
+#endif
+
+	/* note: currently we don't attempt to deal with invalid utf8 chars */
+	BLI_STR_UTF8_CPY(dst, src, maxncpy);
+
+	return (size_t)(dst - r_dst);
+}
+
 char *BLI_strncat_utf8(char *__restrict dst, const char *__restrict src, size_t maxncpy)
 {
 	while (*dst && maxncpy > 0) {
@@ -233,6 +249,7 @@ char *BLI_strncat_utf8(char *__restrict dst, const char *__restrict src, size_t
 size_t BLI_strncpy_wchar_as_utf8(char *__restrict dst, const wchar_t *__restrict src, const size_t maxncpy)
 {
 	const size_t maxlen = maxncpy - 1;
+	const int64_t maxlen_secured = (int64_t)maxlen - 6;  /* 6 is max utf8 length of an unicode char. */
 	size_t len = 0;
 
 	BLI_assert(maxncpy != 0);
@@ -241,10 +258,23 @@ size_t BLI_strncpy_wchar_as_utf8(char *__restrict dst, const wchar_t *__restrict
 	memset(dst, 0xff, sizeof(*dst) * maxncpy);
 #endif
 
-	while (*src && len < maxlen) { /* XXX can still run over the buffer because utf8 size isn't known :| */
+	while (*src && len <= maxlen_secured) {
 		len += BLI_str_utf8_from_unicode((unsigned int)*src++, dst + len);
 	}
 
+	/* We have to be more careful for the last six bytes, to avoid buffer overflow in case utf8-encoded char
+	 * would be too long for our dst buffer. */
+	while (*src) {
+		char t[6];
+		size_t l = BLI_str_utf8_from_unicode((unsigned int)*src++, t);
+		BLI_assert(l <= 6);
+		if (len + l > maxlen) {
+			break;
+		}
+		memcpy(dst + len, t, l);
+		len += l;
+	}
+
 	dst[len] = '\0';
 
 	return len;