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// mirror files from upstream NVD source
package nvdmirror
import (
"fmt"
"github.com/pablotron/cvez/atomictemp"
"github.com/rs/zerolog/log"
"io"
"net/http"
"net/url"
"path/filepath"
"time"
)
// default user agent (FIXME: make configurable)
var defaultUserAgent = "cvez/0.1.0"
// Sync() configuration.
type SyncConfig struct {
// CVE 1.1 Base URL. The full meta and JSON URLs are constructed by
// appending the file name to this base.
Cve11BaseUrl string
// CPE 1.0 base URL. The full meta and JSON URLs are constructed by
// appending the file name to this base.
Cpe10MatchBaseUrl string
// CPE 2.3 dictionary URL.
Cpe23DictUrl string
// User agent string. Set to "" for default user agent string.
UserAgent string
// Maximum number of idle connections.
MaxIdleConns int
// Idle connection timeout.
IdleConnTimeout time.Duration
}
// Get user agent string.
func (me SyncConfig) GetUserAgent() string {
if len(me.UserAgent) > 0 {
return me.UserAgent
} else {
return defaultUserAgent
}
}
// NVD URLs
var DefaultConfig = SyncConfig {
Cve11BaseUrl: "https://nvd.nist.gov/feeds/json/cve/1.1",
Cpe10MatchBaseUrl: "https://nvd.nist.gov/feeds/json/cpematch/1.0",
Cpe23DictUrl: "https://nvd.nist.gov/feeds/xml/cpe/dictionary/official-cpe-dictionary_v2.3.xml.gz",
}
var extraFiles = []string {
"nvdcve-1.1-modified",
"nvdcve-1.1-recent",
}
// fetch result
type fetchResult struct {
src string // source URL
err error // fetch result
modified bool // was the result modified?
lastModified string // last modified response header
etag string // etag response header
}
// base CVE year
const baseYear = 2002
func fetch(ch chan fetchResult, config SyncConfig, cache Cache, client *http.Client, srcUrl string, dstDir string) {
// parse source url
src, err := url.Parse(srcUrl)
if err != nil {
ch <- fetchResult { src: srcUrl, err: err }
return
}
// build destination path
path := filepath.Join(dstDir, filepath.Base(src.Path))
log.Debug().Str("url", srcUrl).Str("path", path).Send()
// create request
req, err := http.NewRequest("GET", srcUrl, nil)
if err != nil {
ch <- fetchResult { src: srcUrl, err: err }
return
}
// add request headers
req.Header.Add("user-agent", config.GetUserAgent())
if headers, ok := cache.Get(srcUrl); ok {
for k, v := range(headers) {
req.Header.Add(k, v)
}
}
// send request
resp, err := client.Do(req)
if err != nil {
ch <- fetchResult { src: srcUrl, err: err }
return
}
defer resp.Body.Close()
switch resp.StatusCode {
case 200:
// create temporary output file
err := atomictemp.Create(path, func(f io.Writer) error {
_, err := io.Copy(f, resp.Body)
return err
})
if err != nil {
// write failed
ch <- fetchResult { src: srcUrl, err: err, modified: false }
} else {
ch <- fetchResult {
src: srcUrl,
modified: true,
lastModified: resp.Header.Get("last-modified"),
etag: resp.Header.Get("etag"),
}
}
case 304:
ch <- fetchResult { src: srcUrl, modified: false }
default:
code := resp.StatusCode
err := fmt.Errorf("%d: %s", code, http.StatusText(code))
ch <- fetchResult { src: srcUrl, err: err }
}
}
func Sync(config SyncConfig, cache Cache, dstDir string) error {
log.Debug().Str("dstDir", dstDir).Msg("Sync")
// create fetch result channel
ch := make(chan fetchResult)
// create shared transport and client
tr := &http.Transport{
MaxIdleConns: config.MaxIdleConns,
IdleConnTimeout: config.IdleConnTimeout,
}
client := &http.Client{Transport: tr}
// calculate total number of years
numYears := time.Now().Year() - baseYear + 1
// fetch cve feed metas
for year := baseYear; year < baseYear + numYears; year++ {
// build url
url := fmt.Sprintf("%s/nvdcve-1.1-%04d.meta", config.Cve11BaseUrl, year)
log.Debug().Int("year", year).Str("url", url).Send()
go fetch(ch, config, cache, client, url, dstDir)
}
// fetch cve extra file metas
for _, s := range(extraFiles) {
url := fmt.Sprintf("%s/%s.meta", config.Cve11BaseUrl, s)
log.Debug().Str("file", s).Str("url", url).Send()
go fetch(ch, config, cache, client, url, dstDir)
}
// read results
for i := 0; i < numYears + len(extraFiles); i++ {
if r := <-ch; r.err != nil {
log.Error().Str("url", r.src).Err(r.err).Send()
// FIXME: errs = append(errs, r)
} else {
log.Info().Str("url", r.src).Str("etag", r.etag).Msg("ok")
if r.modified {
// build request headers
headers := map[string]string {
"if-none-match": r.etag,
"if-modified-since": r.lastModified,
}
// save headers to cache
if err := cache.Set(r.src, headers); err != nil {
log.Error().Str("url", r.src).Err(r.err).Msg("Set")
return err
}
}
}
}
// TODO: fetch cpe dictionary
// TODO: fetch cpematch
// "nvdcpematch-1.0.{meta,json}",
// return success
return nil
}
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