Fix bug #77586 - phar_tar_writeheaders_int() buffer overflow

NEWS

@@ -3,18 +3,19 @@ PHP                                                                        NEWS
 ?? ??? 2019, PHP 7.1.27
 
 - Core:
-  . Fixed bug #77630 (rename() across the device may allow unwanted access during 
+  . Fixed bug #77630 (rename() across the device may allow unwanted access during
     processing). (Stas)
-	
+
 - EXIF:
   . Fixed bug #77509 (Uninitialized read in exif_process_IFD_in_TIFF). (Stas)
-  . Fixed bug #77540 (Invalid Read on exif_process_SOFn). (Stas) 
-  . Fixed bug #77563 (Uninitialized read in exif_process_IFD_in_MAKERNOTE). (Stas) 
+  . Fixed bug #77540 (Invalid Read on exif_process_SOFn). (Stas)
+  . Fixed bug #77563 (Uninitialized read in exif_process_IFD_in_MAKERNOTE). (Stas)
   . Fixed bug #77659 (Uninitialized read in exif_process_IFD_in_MAKERNOTE). (Stas)
 
 - PHAR:
   . Fixed bug #77396 (Null Pointer Dereference in phar_create_or_parse_filename).
-    (bishop) 
+    (bishop)
+  . Fixed bug #77586 (phar_tar_writeheaders_int() buffer overflow). (bishop)
 
 - SPL:
   . Fixed bug #77431 (openFile() silently truncates after a null byte). (cmb)

ext/phar/tar.c

@@ -762,7 +762,12 @@ static int phar_tar_writeheaders_int(phar_entry_info *entry, void *argument) /*
 	header.typeflag = entry->tar_type;
 
 	if (entry->link) {
-		strncpy(header.linkname, entry->link, strlen(entry->link));
+		if (strlcpy(header.linkname, entry->link, sizeof(header.linkname)) >= sizeof(header.linkname)) {
+			if (fp->error) {
+				spprintf(fp->error, 4096, "tar-based phar \"%s\" cannot be created, link \"%s\" is too long for format", entry->phar->fname, entry->link);
+			}
+			return ZEND_HASH_APPLY_STOP;
+		}
 	}
 
 	strncpy(header.magic, "ustar", sizeof("ustar")-1);

ext/phar/tests/bug71488.phpt

@@ -13,5 +13,6 @@ DONE
 <?php
 @unlink(__DIR__."/bug71488.test");
 ?>
---EXPECT--
-DONE
+--EXPECTF--
+Fatal error: Uncaught BadMethodCallException: tar-based phar "%s/bug71488.test" cannot be created, link "%s" is too long for format in %sbug71488.php:%d
+Stack trace:%A

ext/phar/tests/bug77586.phpt

@@ -0,0 +1,21 @@
+--TEST--
+Bug #77586 Symbolic link names in tar-formatted phar must be less than 100 bytes.
+--SKIPIF--
+<?php if (!extension_loaded("phar") || true /* blocked by bug 65332 */) die("skip"); ?>
+--FILE--
+<?php
+$dir = __DIR__."/bug77586";
+$phar = new PharData($dir . "/bug77586.tar");
+$phar->buildFromDirectory($dir . "/files");
+?>
+--CLEAN--
+<?php
+$dir = __DIR__."/bug77586";
+unlink($dir . "/bug77586.tar");
+?>
+--EXPECTF--
+Fatal error: Uncaught PharException: tar-based phar "%s/bug77586.tar" cannot be created, link "%s" is too long for format %s
+Stack trace:
+#0 %s/bug77586.php(%d): PharData->buildFromDirectory('%s')
+#1 {main}
+  thrown in %s/bug77586.php %s on line %d

ext/phar/tests/bug77586/files/link-nktarAMLdJBv7BGYnpzg-ZDycSpWN3Ne3kacltOSE-EqfhStJ1EoBpGuoua6VE-dne29hvpNWXiVbepwIf8-NRHWM9LITLo3nXZnKVNC

@@ -0,0 +1 @@
+target