fix: improve xml2 checker (#2508)

Drop the very convoluted guess_xml2_version function and instead use
standard VERSION_PATTERNS which is working perfectly fine

Signed-off-by: Fabrice Fontaine <fabrice.fontaine@orange.com>

cve_bin_tool/checkers/xml2.py

@@ -12,8 +12,6 @@
 """
 from __future__ import annotations
 
-import re
-
 from cve_bin_tool.checkers import Checker
 
 
@@ -24,49 +22,8 @@ class Xml2Checker(Checker):
         r"xmlRelaxNG: include %s has a define %s but not the included grammar",
     ]
     FILENAME_PATTERNS = [r"libxml2.so."]
-    VERSION_PATTERNS: list[str] = []
+    VERSION_PATTERNS: list[str] = [
+        r"libxml2-([0-9]+\.[0-9]+\.[0-9]+)",
+        r"libxml2.so.([0-9]+\.[0-9]+\.[0-9]+)",
+    ]
     VENDOR_PRODUCT = [("xmlsoft", "libxml2")]
-
-    @staticmethod
-    def guess_xml2_version(lines):
-        """Guesses the xml2 version from the file contents"""
-        new_guess = ""
-        pattern1 = re.compile(r"/libxml2-([0-9]+\.[0-9]+\.[0-9]+)/")
-        pattern2 = re.compile(r"\\libxml2-([0-9]+\.[0-9]+\.[0-9]+)\\")
-        # fedora 29 string looks like libxml2.so.2.9.8-2.9.8-4.fc29.x86_64.debug
-        pattern3 = re.compile(r"libxml2.so.([0-9]+\.[0-9]+\.[0-9]+)")
-
-        for line in lines.splitlines():
-            match = pattern1.search(line)
-            if match:
-                new_guess2 = match.group(1).strip()
-                if len(new_guess2) > len(new_guess):
-                    new_guess = new_guess2
-
-            match = pattern2.search(line)
-            if match:
-                new_guess2 = match.group(1).strip()
-                if len(new_guess2) > len(new_guess):
-                    new_guess = new_guess2
-            if line == "20901":
-                new_guess = "2.9.1"
-            if line == "20902":
-                new_guess = "2.9.2"
-            if line == "20903":
-                new_guess = "2.9.3"
-            if line == "20904":
-                new_guess = "2.9.4"
-
-            match = pattern3.search(line)
-            if match:
-                new_guess2 = match.group(1).strip()
-                if len(new_guess2) > len(new_guess):
-                    new_guess = new_guess2
-        # If no version guessed, set version to "UNKNOWN"
-        return new_guess or "UNKNOWN"
-
-    def get_version(self, lines, filename):
-        version_info = super().get_version(lines, filename)
-        if version_info:
-            version_info["version"] = self.guess_xml2_version(lines)
-        return version_info