Fix #79200: Some iconv functions cut Windows-1258

To cater to potentially state-dependent encodings, we have to reset the
conversion descriptor into its initial shift state to properly finish
the conversion.  Furthermore, state-dependent encodings may not show
progress when comparing `in_left` before and after the conversion; we
rather have to see whether `out_left` has decreased.  Also we have to
cater to the fact that the final potentially state resetting call does
not signal failure, but we still have to break respective loops
afterwards.

Author: cmb69

NEWS

@@ -13,6 +13,9 @@ PHP                                                                        NEWS
   . Fixed bug #79396 (DateTime hour incorrect during DST jump forward). (Nate
     Brunette)
 
+- Iconv:
+  . Fixed bug #79200 (Some iconv functions cut Windows-1258). (cmb)
+
 - SimpleXML:
   . Fixed bug #61597 (SXE properties may lack attributes and content). (cmb)
 

ext/iconv/iconv.c

@@ -739,6 +739,7 @@ static php_iconv_err_t _php_iconv_strlen(size_t *pretval, const char *str, size_
 	size_t out_left;
 
 	size_t cnt;
+	int more;
 
 	*pretval = (size_t)-1;
 
@@ -758,25 +759,23 @@ static php_iconv_err_t _php_iconv_strlen(size_t *pretval, const char *str, size_
 
 	errno = 0;
 	out_left = 0;
+	more = nbytes > 0;
 
-	for (in_p = str, in_left = nbytes, cnt = 0; in_left > 0; cnt+=2) {
-		size_t prev_in_left;
+	for (in_p = str, in_left = nbytes, cnt = 0; more;) {
 		out_p = buf;
 		out_left = sizeof(buf);
 
-		prev_in_left = in_left;
+		more = in_left > 0;
 
-		if (iconv(cd, (char **)&in_p, &in_left, (char **) &out_p, &out_left) == (size_t)-1) {
-			if (prev_in_left == in_left) {
-				break;
-			}
+		iconv(cd, more ? (char **)&in_p : NULL, more ? &in_left : NULL, (char **) &out_p, &out_left);
+		if (out_left == sizeof(buf)) {
+			break;
+		} else {
+			ZEND_ASSERT((sizeof(buf) - out_left) % GENERIC_SUPERSET_NBYTES == 0);
+			cnt += (sizeof(buf) - out_left) / GENERIC_SUPERSET_NBYTES;
 		}
 	}
 
-	if (out_left > 0) {
-		cnt -= out_left / GENERIC_SUPERSET_NBYTES;
-	}
-
 #if ICONV_SUPPORTS_ERRNO
 	switch (errno) {
 		case EINVAL:
@@ -825,6 +824,7 @@ static php_iconv_err_t _php_iconv_substr(smart_str *pretval,
 
 	size_t cnt;
 	size_t total_len;
+	int more;
 
 	err = _php_iconv_strlen(&total_len, str, nbytes, enc);
 	if (err != PHP_ICONV_ERR_SUCCESS) {
@@ -879,18 +879,17 @@ static php_iconv_err_t _php_iconv_substr(smart_str *pretval,
 
 	cd2 = (iconv_t)NULL;
 	errno = 0;
+	more = nbytes > 0 && len > 0;
 
-	for (in_p = str, in_left = nbytes, cnt = 0; in_left > 0 && len > 0; ++cnt) {
-		size_t prev_in_left;
+	for (in_p = str, in_left = nbytes, cnt = 0; more; ++cnt) {
 		out_p = buf;
 		out_left = sizeof(buf);
 
-		prev_in_left = in_left;
+		more = in_left > 0 && len > 0;
 
-		if (iconv(cd1, (char **)&in_p, &in_left, (char **) &out_p, &out_left) == (size_t)-1) {
-			if (prev_in_left == in_left) {
-				break;
-			}
+		iconv(cd1, more ? (char **)&in_p : NULL, more ? &in_left : NULL, (char **) &out_p, &out_left);
+		if (out_left == sizeof(buf)) {
+			break;
 		}
 
 		if ((zend_long)cnt >= offset) {
@@ -978,6 +977,8 @@ static php_iconv_err_t _php_iconv_strpos(size_t *pretval,
 	size_t ndl_buf_left;
 
 	size_t match_ofs;
+	int more;
+	size_t iconv_ret;
 
 	*pretval = (size_t)-1;
 
@@ -1010,37 +1011,38 @@ static php_iconv_err_t _php_iconv_strpos(size_t *pretval,
 	ndl_buf_p = ZSTR_VAL(ndl_buf);
 	ndl_buf_left = ZSTR_LEN(ndl_buf);
 	match_ofs = (size_t)-1;
+	more = haystk_nbytes > 0;
 
-	for (in_p = haystk, in_left = haystk_nbytes, cnt = 0; in_left > 0; ++cnt) {
-		size_t prev_in_left;
+	for (in_p = haystk, in_left = haystk_nbytes, cnt = 0; more; ++cnt) {
 		out_p = buf;
 		out_left = sizeof(buf);
 
-		prev_in_left = in_left;
+		more = in_left > 0;
 
-		if (iconv(cd, (char **)&in_p, &in_left, (char **) &out_p, &out_left) == (size_t)-1) {
-			if (prev_in_left == in_left) {
+		iconv_ret = iconv(cd, more ? (char **)&in_p : NULL, more ? &in_left : NULL, (char **) &out_p, &out_left);
+		if (out_left == sizeof(buf)) {
+			break;
+		}
 #if ICONV_SUPPORTS_ERRNO
-				switch (errno) {
-					case EINVAL:
-						err = PHP_ICONV_ERR_ILLEGAL_CHAR;
-						break;
+		if (iconv_ret == (size_t)-1) {
+			switch (errno) {
+				case EINVAL:
+					err = PHP_ICONV_ERR_ILLEGAL_CHAR;
+					break;
 
-					case EILSEQ:
-						err = PHP_ICONV_ERR_ILLEGAL_SEQ;
-						break;
+				case EILSEQ:
+					err = PHP_ICONV_ERR_ILLEGAL_SEQ;
+					break;
 
-					case E2BIG:
-						break;
+				case E2BIG:
+					break;
 
-					default:
-						err = PHP_ICONV_ERR_UNKNOWN;
-						break;
-				}
-#endif
-				break;
+				default:
+					err = PHP_ICONV_ERR_UNKNOWN;
+					break;
 			}
 		}
+#endif
 		if (offset >= 0) {
 			if (cnt >= (size_t)offset) {
 				if (_php_iconv_memequal(buf, ndl_buf_p, sizeof(buf))) {
@@ -2012,6 +2014,13 @@ static php_iconv_err_t _php_iconv_mime_decode(smart_str *pretval, const char *st
 		*next_pos = p1;
 	}
 
+	if (cd != (iconv_t)(-1)) {
+		_php_iconv_appendl(pretval, NULL, 0, cd);
+	}
+	if (cd_pl != (iconv_t)(-1)) {
+		_php_iconv_appendl(pretval, NULL, 0, cd_pl);
+	}
+
 	smart_str_0(pretval);
 out:
 	if (cd != (iconv_t)(-1)) {

ext/iconv/tests/bug79200.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Bug #79200 (Some iconv functions cut Windows-1258)
+--SKIPIF--
+<?php
+if (!extension_loaded('iconv')) die('skip iconv extension not available');
+?>
+--FILE--
+<?php
+var_dump(iconv_mime_decode('=?windows-1258?Q?test=20test?=', 0, 'UTF-8'));
+var_dump(iconv_strlen('test test', 'WINDOWS-1258'));
+var_dump(iconv_strpos('test test', 'test test', 0, 'WINDOWS-1258'));
+var_dump(iconv_substr('test test', 0 , 9, 'WINDOWS-1258'));
+?>
+--EXPECT--
+string(9) "test test"
+int(9)
+int(0)
+string(9) "test test"