From 887a7b571407f7a49a5e7cf1e612d21ef83fedb4 Mon Sep 17 00:00:00 2001
From: Stanislav Malyshev <stas@php.net>
Date: Tue, 2 Apr 2019 00:12:26 -0700
Subject: [PATCH] Fixed bug #77831 - Heap-buffer-overflow in exif_iif_add_value
 in EXIF

---
 NEWS                         |   1 +
 ext/exif/exif.c              |  43 ++++++++++++++++++++++++++++---------------
 ext/exif/tests/bug77831.phpt |  13 +++++++++++++
 ext/exif/tests/bug77831.tiff | Bin 0 -> 49 bytes
 4 files changed, 42 insertions(+), 15 deletions(-)
 create mode 100644 ext/exif/tests/bug77831.phpt
 create mode 100644 ext/exif/tests/bug77831.tiff

diff --git a/ext/exif/exif.c b/ext/exif/exif.c
index 0b5bb5a..408bf03 100644
--- a/ext/exif/exif.c
+++ b/ext/exif/exif.c
@@ -1654,10 +1654,10 @@ static int exif_file_sections_free(image_info_type *ImageInfo)
 /* {{{ exif_iif_add_value
  Add a value to image_info
 */
-static void exif_iif_add_value(image_info_type *image_info, int section_index, char *name, int tag, int format, int length, void* value, int motorola_intel)
+static void exif_iif_add_value(image_info_type *image_info, int section_index, char *name, int tag, int format, int length, void* value, size_t value_len, int motorola_intel)
 {
 	size_t idex;
-	void *vptr;
+	void *vptr, *vptr_end;
 	image_info_value *info_value;
 	image_info_data  *info_data;
 	image_info_data  *list;
@@ -1679,8 +1679,12 @@ static void exif_iif_add_value(image_info_type *image_info, int section_index, c
 
 	switch (format) {
 		case TAG_FMT_STRING:
+			if (length > value_len) {
+				exif_error_docref("exif_iif_add_value" EXIFERR_CC, image_info, E_WARNING, "length > value_len: %d > %zu", length, value_len);
+				value = NULL;
+			}
 			if (value) {
-				length = php_strnlen(value, length);
+				length = (int)php_strnlen(value, length);
 				info_value->s = estrndup(value, length);
 				info_data->length = length;
 			} else {
@@ -1702,6 +1706,10 @@ static void exif_iif_add_value(image_info_type *image_info, int section_index, c
 			if (!length)
 				break;
 		case TAG_FMT_UNDEFINED:
+			if (length > value_len) {
+				exif_error_docref("exif_iif_add_value" EXIFERR_CC, image_info, E_WARNING, "length > value_len: %d > %zu", length, value_len);
+				value = NULL;
+			}
 			if (value) {
 				if (tag == TAG_MAKER_NOTE) {
 					length = (int) php_strnlen(value, length);
@@ -1732,7 +1740,12 @@ static void exif_iif_add_value(image_info_type *image_info, int section_index, c
 			} else {
 				info_value = &info_data->value;
 			}
+			vptr_end = value+value_len;
 			for (idex=0,vptr=value; idex<(size_t)length; idex++,vptr=(char *) vptr + php_tiff_bytes_per_format[format]) {
+				if (vptr_end - vptr < php_tiff_bytes_per_format[format]) {
+					exif_error_docref("exif_iif_add_value" EXIFERR_CC, image_info, E_WARNING, "Value too short");
+					break;
+				}
 				if (length>1) {
 					info_value = &info_data->value.list[idex];
 				}
@@ -1768,7 +1781,7 @@ static void exif_iif_add_value(image_info_type *image_info, int section_index, c
 						php_error_docref(NULL, E_WARNING, "Found value of type single");
 #endif
 						info_value->f = *(float *)value;
-
+						break;
 					case TAG_FMT_DOUBLE:
 #ifdef EXIF_DEBUG
 						php_error_docref(NULL, E_WARNING, "Found value of type double");
@@ -1786,9 +1799,9 @@ static void exif_iif_add_value(image_info_type *image_info, int section_index, c
 /* {{{ exif_iif_add_tag
  Add a tag from IFD to image_info
 */
-static void exif_iif_add_tag(image_info_type *image_info, int section_index, char *name, int tag, int format, size_t length, void* value)
+static void exif_iif_add_tag(image_info_type *image_info, int section_index, char *name, int tag, int format, size_t length, void* value, size_t value_len)
 {
-	exif_iif_add_value(image_info, section_index, name, tag, format, (int)length, value, image_info->motorola_intel);
+	exif_iif_add_value(image_info, section_index, name, tag, format, (int)length, value, value_len, image_info->motorola_intel);
 }
 /* }}} */
 
@@ -2209,7 +2222,7 @@ static void add_assoc_image_info(zval *value, int sub_array, image_info_type *im
 */
 static void exif_process_COM (image_info_type *image_info, char *value, size_t length)
 {
-	exif_iif_add_tag(image_info, SECTION_COMMENT, "Comment", TAG_COMPUTED_VALUE, TAG_FMT_STRING, length-2, value+2);
+	exif_iif_add_tag(image_info, SECTION_COMMENT, "Comment", TAG_COMPUTED_VALUE, TAG_FMT_STRING, length-2, value+2, length-2);
 }
 /* }}} */
 
@@ -2224,17 +2237,17 @@ static void exif_process_CME (image_info_type *image_info, char *value, size_t l
 	if (length>3) {
 		switch(value[2]) {
 			case 0:
-				exif_iif_add_tag(image_info, SECTION_COMMENT, "Comment", TAG_COMPUTED_VALUE, TAG_FMT_UNDEFINED, length, value);
+				exif_iif_add_tag(image_info, SECTION_COMMENT, "Comment", TAG_COMPUTED_VALUE, TAG_FMT_UNDEFINED, length, value), length;
 				break;
 			case 1:
-				exif_iif_add_tag(image_info, SECTION_COMMENT, "Comment", TAG_COMPUTED_VALUE, TAG_FMT_STRING, length, value);
+				exif_iif_add_tag(image_info, SECTION_COMMENT, "Comment", TAG_COMPUTED_VALUE, TAG_FMT_STRING, length, value, length);
 				break;
 			default:
 				php_error_docref(NULL, E_NOTICE, "Undefined JPEG2000 comment encoding");
 				break;
 		}
 	} else {
-		exif_iif_add_tag(image_info, SECTION_COMMENT, "Comment", TAG_COMPUTED_VALUE, TAG_FMT_UNDEFINED, 0, NULL);
+		exif_iif_add_tag(image_info, SECTION_COMMENT, "Comment", TAG_COMPUTED_VALUE, TAG_FMT_UNDEFINED, 0, NULL, 0);
 		php_error_docref(NULL, E_NOTICE, "JPEG2000 comment section too small");
 	}
 }
@@ -2827,7 +2840,7 @@ static int exif_process_IFD_in_MAKERNOTE(image_info_type *ImageInfo, char * valu
 static int exif_process_IFD_TAG(image_info_type *ImageInfo, char *dir_entry, char *offset_base, size_t IFDlength, size_t displacement, int section_index, int ReadNextIFD, tag_table_type tag_table)
 {
 	size_t length;
-	int tag, format, components;
+	unsigned int tag, format, components;
 	char *value_ptr, tagname[64], cbuf[32], *outside=NULL;
 	size_t byte_count, offset_val, fpos, fgot;
 	int64_t byte_count_signed;
@@ -3138,7 +3151,7 @@ static int exif_process_IFD_TAG(image_info_type *ImageInfo, char *dir_entry, cha
 				}
 		}
 	}
-	exif_iif_add_tag(ImageInfo, section_index, exif_get_tagname(tag, tagname, sizeof(tagname), tag_table), tag, format, components, value_ptr);
+	exif_iif_add_tag(ImageInfo, section_index, exif_get_tagname(tag, tagname, sizeof(tagname), tag_table), tag, format, components, value_ptr, byte_count);
 	EFREE_IF(outside);
 	return TRUE;
 }
@@ -3296,10 +3309,10 @@ static void exif_process_APP12(image_info_type *ImageInfo, char *buffer, size_t
 	size_t l1, l2=0;
 
 	if ((l1 = php_strnlen(buffer+2, length-2)) > 0) {
-		exif_iif_add_tag(ImageInfo, SECTION_APP12, "Company", TAG_NONE, TAG_FMT_STRING, l1, buffer+2);
+		exif_iif_add_tag(ImageInfo, SECTION_APP12, "Company", TAG_NONE, TAG_FMT_STRING, l1, buffer+2, l1);
 		if (length > 2+l1+1) {
 			l2 = php_strnlen(buffer+2+l1+1, length-2-l1-1);
-			exif_iif_add_tag(ImageInfo, SECTION_APP12, "Info", TAG_NONE, TAG_FMT_STRING, l2, buffer+2+l1+1);
+			exif_iif_add_tag(ImageInfo, SECTION_APP12, "Info", TAG_NONE, TAG_FMT_STRING, l2, buffer+2+l1+1, l2);
 		}
 	}
 #ifdef EXIF_DEBUG
@@ -4100,7 +4113,7 @@ PHP_FUNCTION(exif_read_data)
 	if (ImageInfo.Thumbnail.size) {
 		if (read_thumbnail) {
 			/* not exif_iif_add_str : this is a buffer */
-			exif_iif_add_tag(&ImageInfo, SECTION_THUMBNAIL, "THUMBNAIL", TAG_NONE, TAG_FMT_UNDEFINED, ImageInfo.Thumbnail.size, ImageInfo.Thumbnail.data);
+			exif_iif_add_tag(&ImageInfo, SECTION_THUMBNAIL, "THUMBNAIL", TAG_NONE, TAG_FMT_UNDEFINED, ImageInfo.Thumbnail.size, ImageInfo.Thumbnail.data, ImageInfo.Thumbnail.size);
 		}
 		if (!ImageInfo.Thumbnail.width || !ImageInfo.Thumbnail.height) {
 			/* try to evaluate if thumbnail data is present */
diff --git a/ext/exif/tests/bug77831.phpt b/ext/exif/tests/bug77831.phpt
new file mode 100644
index 0000000..d868d47
--- /dev/null
+++ b/ext/exif/tests/bug77831.phpt
@@ -0,0 +1,13 @@
+--TEST--
+Bug #77831 (Heap-buffer-overflow in exif_iif_add_value in EXIF)
+--SKIPIF--
+<?php if (!extension_loaded('exif')) print 'skip exif extension not available';?>
+--FILE--
+<?php
+var_dump(exif_read_data(__DIR__."/bug77831.tiff"));
+?>
+DONE
+--EXPECTF--
+%A
+bool(false)
+DONE
\ No newline at end of file

-- 
2.1.4

