[OE-core] [PATCH 6/6] cve-check: fetch CVE data once at a time instead of in a single call

[Ross Burton]

This code used to construct a single SQL statement that fetched the NVD data for
every CVE requested.  For recipes such as the kernel where there are over 2000
CVEs to report this can hit the variable count limit and the query fails with
"sqlite3.OperationalError: too many SQL variables".  The default limit is 999
variables, but some distributions such as Debian set the default to 250000.

As the NVD table has an index on the ID column, whilst requesting the data
CVE-by-CVE is five times slower when working with 2000 CVEs the absolute time
different is insignificant: 0.05s verses 0.01s on my machine.

Signed-off-by: Ross Burton <ross.burton at intel.com>
---
 meta/classes/cve-check.bbclass | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/meta/classes/cve-check.bbclass b/meta/classes/cve-check.bbclass
index e95716d9ded..19ed5548b3a 100644
--- a/meta/classes/cve-check.bbclass
+++ b/meta/classes/cve-check.bbclass
@@ -267,17 +267,17 @@ def get_cve_info(d, cves):
 
     cve_data = {}
     conn = sqlite3.connect(d.getVar("CVE_CHECK_DB_FILE"))
-    placeholders = ",".join("?" * len(cves))
-    query = "SELECT * FROM NVD WHERE id IN (%s)" % placeholders
-    for row in conn.execute(query, tuple(cves)):
-        cve_data[row[0]] = {}
-        cve_data[row[0]]["summary"] = row[1]
-        cve_data[row[0]]["scorev2"] = row[2]
-        cve_data[row[0]]["scorev3"] = row[3]
-        cve_data[row[0]]["modified"] = row[4]
-        cve_data[row[0]]["vector"] = row[5]
-    conn.close()
 
+    for cve in cves:
+        for row in conn.execute("SELECT * FROM NVD WHERE ID IS ?", (cve,)):
+            cve_data[row[0]] = {}
+            cve_data[row[0]]["summary"] = row[1]
+            cve_data[row[0]]["scorev2"] = row[2]
+            cve_data[row[0]]["scorev3"] = row[3]
+            cve_data[row[0]]["modified"] = row[4]
+            cve_data[row[0]]["vector"] = row[5]
+
+    conn.close()
     return cve_data
 
 def cve_write_data(d, patched, unpatched, cve_data):
-- 
2.20.1