cve-check: Fix false negative version issue

NVD DB store version and update in the same value, separated by '_'.
The proposed patch check if the version from NVD DB contains a "_",
ie 9.2.0_p1 is convert to 9.2.0p1 before version comparison.

[YOCTO #14127]

Reviewed-by: Yoann CONGAL <yoann.congal@smile.fr>
(From OE-Core rev: 7d00f6ec578084a0a0e5caf36241d53036d996c4)

Signed-off-by: Geoffrey GIRY <geoffrey.giry@smile.fr>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/cve-check.bbclass

@@ -260,7 +260,7 @@ def check_cves(d, patched_cves):
     """
     Connect to the NVD database and find unpatched cves.
     """
-    from oe.cve_check import Version
+    from oe.cve_check import Version, convert_cve_version
 
     pn = d.getVar("PN")
     real_pv = d.getVar("PV")
@@ -324,6 +324,9 @@ def check_cves(d, patched_cves):
                 if cve in cve_ignore:
                     ignored = True
 
+                version_start = convert_cve_version(version_start)
+                version_end = convert_cve_version(version_end)
+
                 if (operator_start == '=' and pv == version_start) or version_start == '-':
                     vulnerable = True
                 else:

meta/lib/oe/cve_check.py

@@ -179,3 +179,42 @@ def update_symlinks(target_path, link_path):
         if os.path.exists(os.path.realpath(link_path)):
             os.remove(link_path)
         os.symlink(os.path.basename(target_path), link_path)
+
+
+def convert_cve_version(version):
+    """
+    This function converts from CVE format to Yocto version format.
+    eg 8.3_p1 -> 8.3p1, 6.2_rc1 -> 6.2-rc1
+
+    Unless it is redefined using CVE_VERSION in the recipe,
+    cve_check uses the version in the name of the recipe (${PV})
+    to check vulnerabilities against a CVE in the database downloaded from NVD.
+
+    When the version has an update, i.e.
+    "p1" in OpenSSH 8.3p1,
+    "-rc1" in linux kernel 6.2-rc1,
+    the database stores the version as version_update (8.3_p1, 6.2_rc1).
+    Therefore, we must transform this version before comparing to the
+    recipe version.
+
+    In this case, the parameter of the function is 8.3_p1.
+    If the version uses the Release Candidate format, "rc",
+    this function replaces the '_' by '-'.
+    If the version uses the Update format, "p",
+    this function removes the '_' completely.
+    """
+    import re
+
+    matches = re.match('^([0-9.]+)_((p|rc)[0-9]+)$', version)
+
+    if not matches:
+        return version
+
+    version = matches.group(1)
+    update = matches.group(2)
+
+    if matches.group(3) == "rc":
+        return version + '-' + update
+
+    return version + update
+

meta/lib/oeqa/selftest/cases/cve_check.py

@@ -54,6 +54,25 @@ class CVECheck(OESelftestTestCase):
         self.assertTrue( result ,msg="Failed to compare version with suffix '1.0_patch2' < '1.0_patch3'")
 
 
+    def test_convert_cve_version(self):
+        from oe.cve_check import convert_cve_version
+
+        # Default format
+        self.assertEqual(convert_cve_version("8.3"), "8.3")
+        self.assertEqual(convert_cve_version(""), "")
+
+        # OpenSSL format version
+        self.assertEqual(convert_cve_version("1.1.1t"), "1.1.1t")
+
+        # OpenSSH format
+        self.assertEqual(convert_cve_version("8.3_p1"), "8.3p1")
+        self.assertEqual(convert_cve_version("8.3_p22"), "8.3p22")
+
+        # Linux kernel format
+        self.assertEqual(convert_cve_version("6.2_rc8"), "6.2-rc8")
+        self.assertEqual(convert_cve_version("6.2_rc31"), "6.2-rc31")
+
+
     def test_recipe_report_json(self):
         config = """
 INHERIT += "cve-check"