Adding upstream version 3.8.1.upstream/3.8.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 157 insertions, 0 deletions

diff --git a/src/libserver/css/css_util.cxx b/src/libserver/css/css_util.cxx
new file mode 100644
index 0000000..07f8722
--- /dev/null
+++ b/src/libserver/css/css_util.cxx
@@ -0,0 +1,157 @@
+/*-
+ * Copyright 2021 Vsevolod Stakhov
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "css_util.hxx"
+#include "css.hxx"
+#include <unicode/utf8.h>
+
+namespace rspamd::css {
+
+std::string_view unescape_css(rspamd_mempool_t *pool,
+							  const std::string_view &sv)
+{
+	auto *nspace = reinterpret_cast<char *>(rspamd_mempool_alloc(pool, sv.length()));
+	auto *d = nspace;
+	auto nleft = sv.length();
+
+	enum {
+		normal = 0,
+		quoted,
+		escape,
+		skip_spaces,
+	} state = normal;
+
+	char quote_char, prev_c = 0;
+	auto escape_offset = 0, i = 0;
+
+#define MAYBE_CONSUME_CHAR(c)            \
+	do {                                 \
+		if ((c) == '"' || (c) == '\'') { \
+			state = quoted;              \
+			quote_char = (c);            \
+			nleft--;                     \
+			*d++ = (c);                  \
+		}                                \
+		else if ((c) == '\\') {          \
+			escape_offset = i;           \
+			state = escape;              \
+		}                                \
+		else {                           \
+			state = normal;              \
+			nleft--;                     \
+			*d++ = g_ascii_tolower(c);   \
+		}                                \
+	} while (0)
+
+	for (const auto c: sv) {
+		if (nleft == 0) {
+			msg_err_css("cannot unescape css: truncated buffer of size %d",
+						(int) sv.length());
+			break;
+		}
+		switch (state) {
+		case normal:
+			MAYBE_CONSUME_CHAR(c);
+			break;
+		case quoted:
+			if (c == quote_char) {
+				if (prev_c != '\\') {
+					state = normal;
+				}
+			}
+			prev_c = c;
+			nleft--;
+			*d++ = c;
+			break;
+		case escape:
+			if (!g_ascii_isxdigit(c)) {
+				if (i > escape_offset + 1) {
+					/* Try to decode an escape */
+					const auto *escape_start = &sv[escape_offset + 1];
+					unsigned long val;
+
+					if (!rspamd_xstrtoul(escape_start, i - escape_offset - 1, &val)) {
+						msg_debug_css("invalid broken escape found at pos %d",
+									  escape_offset);
+					}
+					else {
+						if (val < 0x80) {
+							/* Trivial case: ascii character */
+							*d++ = (unsigned char) g_ascii_tolower(val);
+							nleft--;
+						}
+						else {
+							UChar32 uc = val;
+							auto off = 0;
+							UTF8_APPEND_CHAR_SAFE((uint8_t *) d, off,
+												  sv.length(), u_tolower(uc));
+							d += off;
+							nleft -= off;
+						}
+					}
+				}
+				else {
+					/* Empty escape, ignore it */
+					msg_debug_css("invalid empty escape found at pos %d",
+								  escape_offset);
+				}
+
+				if (nleft <= 0) {
+					msg_err_css("cannot unescape css: truncated buffer of size %d",
+								(int) sv.length());
+				}
+				else {
+					/* Escape is done, advance forward */
+					if (g_ascii_isspace(c)) {
+						state = skip_spaces;
+					}
+					else {
+						MAYBE_CONSUME_CHAR(c);
+					}
+				}
+			}
+			break;
+		case skip_spaces:
+			if (!g_ascii_isspace(c)) {
+				MAYBE_CONSUME_CHAR(c);
+			}
+			/* Ignore spaces */
+			break;
+		}
+
+		i++;
+	}
+
+	return std::string_view{nspace, sv.size() - nleft};
+}
+
+}// namespace rspamd::css
+
+/* C API */
+const gchar *rspamd_css_unescape(rspamd_mempool_t *pool,
+								 const guchar *begin,
+								 gsize len,
+								 gsize *outlen)
+{
+	auto sv = rspamd::css::unescape_css(pool, {(const char *) begin, len});
+	const auto *v = sv.begin();
+
+	if (outlen) {
+		*outlen = sv.size();
+	}
+
+	return v;
+}
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