[libsoup/content-sniffing-update: 4/7] Adjust the general unknown MIME type algorithm
- From: Gustavo Noronha Silva <gns src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [libsoup/content-sniffing-update: 4/7] Adjust the general unknown MIME type algorithm
- Date: Tue, 10 Dec 2013 16:31:38 +0000 (UTC)
commit aae9641993bc9d479ed1ed56d7f3c85efe475d79
Author: Gustavo Noronha Silva <gns gnome org>
Date: Mon Dec 9 11:54:29 2013 +0100
Adjust the general unknown MIME type algorithm
This change adjusts the pattern matching table to the current form of the
MIMESNIFF spec, adding a check for a tag-terminating byte and using the formally
defined sniff-scriptable flag.
libsoup/soup-content-sniffer.c | 241 +++++++++++++++++++++++++++++---------
tests/resources/html_binary.html | 2 +-
2 files changed, 187 insertions(+), 56 deletions(-)
---
diff --git a/libsoup/soup-content-sniffer.c b/libsoup/soup-content-sniffer.c
index d27ef45..0f6f501 100644
--- a/libsoup/soup-content-sniffer.c
+++ b/libsoup/soup-content-sniffer.c
@@ -77,12 +77,15 @@ soup_content_sniffer_init (SoupContentSniffer *content_sniffer)
{
}
-/* This table is based on the HTML5 spec;
- * See 2.7.4 Content-Type sniffing: unknown type
+/* This table is based on the MIMESNIFF spec;
+ * See 7.1 Identifying a resource with an unknown MIME type
*/
typedef struct {
/* @has_ws is TRUE if @pattern contains "generic" whitespace */
gboolean has_ws;
+ /* @has_tag_termination is TRUE if we should check for a tag-terminating
+ * byte (0x20 " " or 0x3E ">") after the pattern match. */
+ gboolean has_tag_termination;
const guchar *mask;
const guchar *pattern;
guint pattern_length;
@@ -90,111 +93,234 @@ typedef struct {
gboolean scriptable;
} SoupContentSnifferPattern;
+
+/* When has_ws is TRUE, spaces in the pattern will indicate where insignificant space
+ * is allowed. Those spaces are marked with \x00 on the mask.
+ */
static SoupContentSnifferPattern types_table[] = {
- { FALSE,
- (const guchar *)"\xFF\xFF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xFF\xDF\xDF\xDF\xDF",
- (const guchar *)"\x3C\x21\x44\x4F\x43\x54\x59\x50\x45\x20\x48\x54\x4D\x4C",
+ /* Scriptable types. */
+
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xFF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xFF\xDF\xDF\xDF\xDF",
+ (const guchar *)" <!DOCTYPE HTML",
14,
"text/html",
TRUE },
- { TRUE,
- (const guchar *)"\xFF\xFF\xDF\xDF\xDF\xDF",
- (const guchar *)" \x3C\x48\x54\x4D\x4C",
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF\xDF\xDF\xDF",
+ (const guchar *)" <HTML",
5,
"text/html",
TRUE },
- { TRUE,
- (const guchar *)"\xFF\xFF\xDF\xDF\xDF\xDF",
- (const guchar *)" \x3C\x48\x45\x41\x44",
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF\xDF\xDF\xDF",
+ (const guchar *)" <HEAD",
5,
"text/html",
TRUE },
- { TRUE,
- (const guchar *)"\xFF\xFF\xDF\xDF\xDF\xDF\xDF\xDF",
- (const guchar *)" \x3C\x53\x43\x52\x49\x50\x54",
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF\xDF\xDF\xDF\xDF\xDF",
+ (const guchar *)" <SCRIPT",
+ 7,
+ "text/html",
+ TRUE },
+
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF\xDF\xDF\xDF\xDF\xDF",
+ (const guchar *)" <IFRAME",
7,
"text/html",
TRUE },
- { FALSE,
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF\xFF",
+ (const guchar *)" <H1",
+ 3,
+ "text/html",
+ TRUE },
+
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF\xDF\xDF",
+ (const guchar *)" <DIV",
+ 4,
+ "text/html",
+ TRUE },
+
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF\xDF\xDF\xDF",
+ (const guchar *)" <FONT",
+ 5,
+ "text/html",
+ TRUE },
+
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF\xDF\xDF\xDF\xDF",
+ (const guchar *)" <TABLE",
+ 6,
+ "text/html",
+ TRUE },
+
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF",
+ (const guchar *)" <A",
+ 2,
+ "text/html",
+ TRUE },
+
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF\xDF\xDF\xDF\xDF",
+ (const guchar *)" <STYLE",
+ 6,
+ "text/html",
+ TRUE },
+
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF\xDF\xDF\xDF\xDF",
+ (const guchar *)" <TITLE",
+ 6,
+ "text/html",
+ TRUE },
+
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF",
+ (const guchar *)" <B",
+ 2,
+ "text/html",
+ TRUE },
+
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF\xDF\xDF\xDF",
+ (const guchar *)" <BODY",
+ 5,
+ "text/html",
+ TRUE },
+
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF\xDF",
+ (const guchar *)" <BR",
+ 3,
+ "text/html",
+ TRUE },
+
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xDF",
+ (const guchar *)" <P",
+ 2,
+ "text/html",
+ TRUE },
+
+ { TRUE, TRUE,
+ (const guchar *)"\x00\xFF\xFF\xFF\xFF",
+ (const guchar *)" <!--",
+ 4,
+ "text/html",
+ TRUE },
+
+ { TRUE, FALSE,
+ (const guchar *)"\x00\xFF\xFF\xFF\xFF\xFF",
+ (const guchar *)" <?xml",
+ 5,
+ "text/html",
+ TRUE },
+
+ { FALSE, FALSE,
(const guchar *)"\xFF\xFF\xFF\xFF\xFF",
- (const guchar *)"\x25\x50\x44\x46\x2D",
+ (const guchar *)"%PDF-",
5,
"application/pdf",
TRUE },
- { FALSE,
+ /* Non-scriptable types. */
+ { FALSE, FALSE,
(const guchar *)"\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF",
- (const guchar *)"\x25\x21\x50\x53\x2D\x41\x64\x6F\x62\x65\x2D",
+ (const guchar *)"%!PS-Adobe-",
11,
"application/postscript",
FALSE },
- { FALSE,
+ { FALSE, FALSE, /* UTF-16BE BOM */
(const guchar *)"\xFF\xFF\x00\x00",
(const guchar *)"\xFE\xFF\x00\x00",
4,
"text/plain",
FALSE },
- { FALSE,
- (const guchar *)"\xFF\xFF\x00\x00",
+ { FALSE, FALSE, /* UTF-16LE BOM */
(const guchar *)"\xFF\xFF\x00\x00",
+ (const guchar *)"\xFF\xFE\x00\x00",
4,
"text/plain",
FALSE },
- { FALSE,
+ { FALSE, FALSE, /* UTF-8 BOM */
(const guchar *)"\xFF\xFF\xFF\x00",
(const guchar *)"\xEF\xBB\xBF\x00",
4,
"text/plain",
FALSE },
- { FALSE,
+ /* Images. */
+
+ { FALSE, FALSE, /* Windows icon signature. */
+ (const guchar *)"\xFF\xFF\xFF\xFF",
+ (const guchar *)"\x00\x00\x01\x00",
+ 4,
+ "image/x-icon",
+ FALSE },
+
+ { FALSE, FALSE, /* Windows cursor signature. */
+ (const guchar *)"\xFF\xFF\xFF\xFF",
+ (const guchar *)"\x00\x00\x02\x00",
+ 4,
+ "image/x-icon",
+ FALSE },
+
+ { FALSE, FALSE, /* BMP. */
+ (const guchar *)"\xFF\xFF",
+ (const guchar *)"BM",
+ 2,
+ "image/bmp",
+ FALSE },
+
+ { FALSE, FALSE, /* GIF. */
(const guchar *)"\xFF\xFF\xFF\xFF\xFF\xFF",
- (const guchar *)"\x47\x49\x46\x38\x37\x61",
+ (const guchar *)"GIF87a",
6,
"image/gif",
FALSE },
- { FALSE,
+ { FALSE, FALSE, /* GIF. */
(const guchar *)"\xFF\xFF\xFF\xFF\xFF\xFF",
- (const guchar *)"\x47\x49\x46\x38\x39\x61",
+ (const guchar *)"GIF89a",
6,
"image/gif",
FALSE },
- { FALSE,
+ { FALSE, FALSE, /* WEBP. */
+ (const guchar *)"\xFF\xFF\xFF\xFF\x00\x00\x00\x00\xFF\xFF\xFF\xFF\xFF\xFF",
+ (const guchar *)"RIFF\x00\x00\x00\x00WEBPVP",
+ 14,
+ "image/webp",
+ FALSE },
+
+ { FALSE, FALSE, /* PNG. */
(const guchar *)"\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF",
- (const guchar *)"\x89\x50\x4E\x47\x0D\x0A\x1A\x0A",
+ (const guchar *)"\x89PNG\x0D\x0A\x1A\x0A",
8,
"image/png",
FALSE },
- { FALSE,
+ { FALSE, FALSE, /* JPEG. */
(const guchar *)"\xFF\xFF\xFF",
(const guchar *)"\xFF\xD8\xFF",
3,
"image/jpeg",
FALSE },
- { FALSE,
- (const guchar *)"\xFF\xFF",
- (const guchar *)"\x42\x4D",
- 2,
- "image/bmp",
- FALSE },
-
- { FALSE,
- (const guchar *)"\xFF\xFF\xFF\xFF",
- (const guchar *)"\x00\x00\x01\x00",
- 4,
- "image/vnd.microsoft.icon",
- FALSE }
+ /* TODO: audio/video, archive type. */
};
/* Whether a given byte looks like it might be part of binary content.
@@ -223,7 +349,7 @@ static char byte_looks_binary[] = {
/* HTML5: 2.7.4 Content-Type sniffing: unknown type */
static char*
sniff_unknown (SoupContentSniffer *sniffer, SoupBuffer *buffer,
- gboolean for_text_or_binary)
+ gboolean sniff_scriptable)
{
const guchar *resource = (const guchar *)buffer->data;
int resource_length = MIN (512, buffer->length);
@@ -232,9 +358,7 @@ sniff_unknown (SoupContentSniffer *sniffer, SoupBuffer *buffer,
for (i = 0; i < G_N_ELEMENTS (types_table); i++) {
SoupContentSnifferPattern *type_row = &(types_table[i]);
- /* The scriptable types should be skiped for the text
- * or binary path, but considered for other paths */
- if (for_text_or_binary && type_row->scriptable)
+ if (!sniff_scriptable && type_row->scriptable)
continue;
if (type_row->has_ws) {
@@ -267,8 +391,14 @@ sniff_unknown (SoupContentSniffer *sniffer, SoupBuffer *buffer,
if (skip_row)
continue;
- if (index_pattern > type_row->pattern_length)
+ if (index_pattern > type_row->pattern_length) {
+ if (type_row->has_tag_termination &&
+ resource[index_stream] != '\x20' &&
+ resource[index_stream] != '\x3E')
+ continue;
+
return g_strdup (type_row->sniffed_type);
+ }
} else {
int j;
@@ -286,9 +416,6 @@ sniff_unknown (SoupContentSniffer *sniffer, SoupBuffer *buffer,
}
}
- if (for_text_or_binary)
- return g_strdup ("application/octet-stream");
-
for (i = 0; i < resource_length; i++) {
if (byte_looks_binary[resource[i]])
return g_strdup ("application/octet-stream");
@@ -478,22 +605,26 @@ soup_content_sniffer_real_sniff (SoupContentSniffer *sniffer, SoupMessage *msg,
{
const char *content_type;
const char *x_content_type_options;
+ gboolean no_sniff = FALSE;
content_type = soup_message_headers_get_content_type (msg->response_headers, params);
/* MIMESNIFF: 7 Determining the sniffed MIME type of a resource. */
- /* 1. Unknown/undefined supplied type respecting sniff-scritable. */
+ x_content_type_options = soup_message_headers_get_one (msg->response_headers,
"X-Content-Type-Options");
+ if ((x_content_type_options != NULL) &&
+ g_str_equal (x_content_type_options, "nosniff"))
+ no_sniff = TRUE;
+
+ /* 1. Unknown/undefined supplied type with sniff-scritable = !nosniff. */
if ((content_type == NULL) ||
!g_ascii_strcasecmp (content_type, "unknown/unknown") ||
!g_ascii_strcasecmp (content_type, "application/unknown") ||
!g_ascii_strcasecmp (content_type, "*/*"))
- return sniff_unknown (sniffer, buffer, FALSE);
+ return sniff_unknown (sniffer, buffer, !no_sniff);
/* 2. If nosniff is specified in X-Content-Type-Options use the supplied MIME type. */
- x_content_type_options = soup_message_headers_get_one (msg->response_headers,
"X-Content-Type-Options");
- if ((x_content_type_options != NULL) &&
- g_str_equal (x_content_type_options, "nosniff"))
+ if (no_sniff)
return g_strdup (content_type);
/* 3. check-for-apache-bug */
diff --git a/tests/resources/html_binary.html b/tests/resources/html_binary.html
index 9200dd4..d443048 100644
--- a/tests/resources/html_binary.html
+++ b/tests/resources/html_binary.html
@@ -1 +1 @@
-<HTML
+<HTML
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