[PATCH v3 04/21] Escape names used in symbol whitelisting regex.

[Giuliano Procida <gprocida@google.com>]

There is the theoretical possibility that symbols may contain special
regex characters like '.' and '$'. This patch ensures all such
characters in symbol names are escaped before they are added to the
whitelisting regex.

	* include/regex.h (escape): New string reference holder
	class. (operator<<): Declaration of std::ostream,
	regex::escape overload.
	* include/regex.cc (operator<<): New std::ostream,
	regex::escape overload that outputs regex-escaped strings.
	* src/abg-tools-utils.cc
	(gen_suppr_spec_from_kernel_abi_whitelists): Make sure any
	special regex characters in symbol names are escaped.

Signed-off-by: Giuliano Procida <gprocida@google.com>
---
 include/abg-regex.h | 10 ++++++++++
 src/abg-regex.cc    | 27 +++++++++++++++++++++++++--
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/include/abg-regex.h b/include/abg-regex.h
index 2f638ef2..59976794 100644
--- a/include/abg-regex.h
+++ b/include/abg-regex.h
@@ -58,6 +58,16 @@ struct regex_t_deleter
   }
 };//end struct regex_deleter
 
+/// A class to hold a reference to a string to regex escape.
+struct escape
+{
+  escape(const std::string& str) : ref(str) { }
+  const std::string& ref;
+};
+
+std::ostream&
+operator<<(std::ostream& os, const escape& esc);
+
 std::string
 generate_from_strings(const std::vector<std::string>& strs);
 
diff --git a/src/abg-regex.cc b/src/abg-regex.cc
index 79a89033..90e4d144 100644
--- a/src/abg-regex.cc
+++ b/src/abg-regex.cc
@@ -24,6 +24,7 @@
 ///
 
 #include <sstream>
+#include <ostream>
 #include "abg-sptr-utils.h"
 #include "abg-regex.h"
 
@@ -56,6 +57,28 @@ sptr_utils::build_sptr<regex_t>()
 namespace regex
 {
 
+/// Escape regex special charaters in input string.
+///
+/// @param os the output stream being written to.
+///
+/// @param esc the regex_escape object holding a reference to the string
+/// needing to be escaped.
+///
+/// @return the output stream.
+std::ostream&
+operator<<(std::ostream& os, const escape& esc)
+{
+  static const std::string specials = "^.[$()|*+?{\\";
+  const std::string str = esc.ref;
+  for (std::string::const_iterator i = str.begin(); i != str.end(); ++i)
+    {
+      if (specials.find(*i) != std::string::npos)
+        os << '\\';
+      os << *i;
+    }
+  return os;
+}
+
 /// Generate a regex pattern equivalent to testing set membership.
 ///
 /// A string will match the resulting pattern regex, if and only if it
@@ -71,9 +94,9 @@ generate_from_strings(const std::vector<std::string>& strs)
     return "^_^";
   std::ostringstream os;
   std::vector<std::string>::const_iterator i = strs.begin();
-  os << "^(" << *i++;
+  os << "^(" << escape(*i++);
   while (i != strs.end())
-    os << "|" << *i++;
+    os << "|" << escape(*i++);
   os << ")$";
   return os.str();
 }
-- 
2.26.2.303.gf8c07b1a785-goog