patterns: test for empty terms, reject them

3 files changed, 30 insertions, 1 deletions

diff --git a/apt-pkg/cachefilter-patterns.cc b/apt-pkg/cachefilter-patterns.cc
index 1c92a7b1f..5a58a9767 100644
--- a/apt-pkg/cachefilter-patterns.cc
+++ b/apt-pkg/cachefilter-patterns.cc
@@ -263,6 +263,9 @@ std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parsePattern()
 
    node->term = sentence.substr(node->start, state.offset - node->start);
 
+   if (node->term.size() <= 1)
+      throw Error{*node, "Pattern must have a term/name"};
+
    node->end = skipSpace();
    // We don't have any arguments, return node;
    if (sentence[state.offset] != '(')
diff --git a/apt-pkg/cachefilter-patterns.h b/apt-pkg/cachefilter-patterns.h
index e79702af8..4eeb68594 100644
--- a/apt-pkg/cachefilter-patterns.h
+++ b/apt-pkg/cachefilter-patterns.h
@@ -92,9 +92,9 @@ struct PatternTreeParser
    /// There may not be anything before or after the pattern, except for
    /// whitespace.
    std::unique_ptr<Node> parseTop();
+   std::unique_ptr<Node> parse(); // public for test cases only
 
    private:
-   std::unique_ptr<Node> parse();
    std::unique_ptr<Node> parseOr();
    std::unique_ptr<Node> parseAnd();
    std::unique_ptr<Node> parseUnary();
diff --git a/test/libapt/pattern_test.cc b/test/libapt/pattern_test.cc
index 84d09351c..bfcaf2093 100644
--- a/test/libapt/pattern_test.cc
+++ b/test/libapt/pattern_test.cc
@@ -14,6 +14,32 @@
 
 using namespace APT::Internal;
 
+#define EXPECT_EXCEPTION(exp, exc, msg)                                                        \
+   caught = false;                                                                             \
+   try                                                                                         \
+   {                                                                                           \
+      exp;                                                                                     \
+   }                                                                                           \
+   catch (exc & e)                                                                             \
+   {                                                                                           \
+      caught = true;                                                                           \
+      EXPECT_TRUE(e.message.find(msg) != std::string::npos) << msg << " not in " << e.message; \
+   };                                                                                          \
+   EXPECT_TRUE(caught) << #exp "should have thrown an exception"
+
+TEST(TreeParserTest, ParseInvalid)
+{
+   bool caught = false;
+
+   // Not a valid pattern: Reject
+   EXPECT_EXCEPTION(PatternTreeParser("?").parse(), PatternTreeParser::Error, "Pattern must have a term");
+   EXPECT_EXCEPTION(PatternTreeParser("?AB?").parse(), PatternTreeParser::Error, "Pattern must have a term");
+   EXPECT_EXCEPTION(PatternTreeParser("~").parse(), PatternTreeParser::Error, "Unknown short pattern");
+
+   // Not a pattern at all: Report nullptr
+   EXPECT_EQ(PatternTreeParser("A?").parse(), nullptr);
+}
+
 TEST(TreeParserTest, ParseWord)
 {
    auto node = PatternTreeParser("?word(word)").parseTop();