mirror of
https://github.com/DNSCrypt/dnscrypt-proxy.git
synced 2024-12-27 00:12:31 +01:00
Verify signature immediately after reading from cache or URL
This allows a large number of tests to be enabled and pass now that the behaviour is expected. The main fix here is that a download with an invalid signature will always fall back on using a properly signed cache, no matter how old it is. Additionally, downloads will never be written to the cache unless they are properly signed (both at startup and prefetching).
This commit is contained in:
William Elwood
Frank Denis
parent
53d5b0f3cd
commit
c0e34d1a9e
@ -51,18 +51,23 @@ func (source *Source) checkSignature(bin, sig []byte) (err error) {
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// timeNow can be replaced by tests to provide a static value
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var timeNow = time.Now
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func (source *Source) fetchFromCache() (bin, sig []byte, delayTillNextUpdate time.Duration, err error) {
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func (source *Source) fetchFromCache() (delayTillNextUpdate time.Duration, err error) {
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delayTillNextUpdate = 0
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var fi os.FileInfo
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if fi, err = os.Stat(source.cacheFile); err != nil {
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return
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}
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var bin, sig []byte
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if bin, err = ioutil.ReadFile(source.cacheFile); err != nil {
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return
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}
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if sig, err = ioutil.ReadFile(source.cacheFile + ".minisig"); err != nil {
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return
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}
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if err = source.checkSignature(bin, sig); err != nil {
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return
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}
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source.in = bin
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var fi os.FileInfo
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if fi, err = os.Stat(source.cacheFile); err != nil {
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return
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}
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if elapsed := timeNow().Sub(fi.ModTime()); elapsed < source.cacheTTL {
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dlog.Debugf("Cache file [%s] is still fresh", source.cacheFile)
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delayTillNextUpdate = source.prefetchDelay - elapsed
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@ -100,8 +105,8 @@ func fetchFromURL(xTransport *XTransport, u *url.URL) (bin []byte, err error) {
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return
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}
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func (source *Source) fetchWithCache(xTransport *XTransport, urlStr string) (bin, sig []byte, delayTillNextUpdate time.Duration, err error) {
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if bin, sig, delayTillNextUpdate, err = source.fetchFromCache(); err != nil {
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func (source *Source) fetchWithCache(xTransport *XTransport, urlStr string) (delayTillNextUpdate time.Duration, err error) {
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if delayTillNextUpdate, err = source.fetchFromCache(); err != nil {
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if len(urlStr) == 0 {
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dlog.Errorf("Cache file [%s] not present and no URL given to retrieve it", source.cacheFile)
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return
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@ -122,12 +127,17 @@ func (source *Source) fetchWithCache(xTransport *XTransport, urlStr string) (bin
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sigURL := &url.URL{}
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*sigURL = *srcURL // deep copy to avoid parsing twice
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sigURL.Path += ".minisig"
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var bin, sig []byte
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if bin, err = fetchFromURL(xTransport, srcURL); err != nil {
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return
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}
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if sig, err = fetchFromURL(xTransport, sigURL); err != nil {
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return
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}
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if err = source.checkSignature(bin, sig); err != nil {
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return
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}
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source.in = bin
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source.writeToCache(bin, sig) // ignore error: not fatal
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delayTillNextUpdate = source.prefetchDelay
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return
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@ -150,13 +160,12 @@ func NewSource(xTransport *XTransport, urls []string, minisignKeyStr string, cac
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}
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now := timeNow()
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var bin, sig []byte
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var delayTillNextUpdate time.Duration
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if len(urls) <= 0 {
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bin, sig, delayTillNextUpdate, err = source.fetchWithCache(xTransport, "")
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delayTillNextUpdate, err = source.fetchWithCache(xTransport, "")
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} else {
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for _, url := range urls {
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bin, sig, delayTillNextUpdate, err = source.fetchWithCache(xTransport, url)
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delayTillNextUpdate, err = source.fetchWithCache(xTransport, url)
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if err == nil {
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break
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}
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@ -168,11 +177,7 @@ func NewSource(xTransport *XTransport, urls []string, minisignKeyStr string, cac
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return
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}
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if err = source.checkSignature(bin, sig); err != nil {
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return
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}
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dlog.Noticef("Source [%s] loaded", cacheFile)
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source.in = bin
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return
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}
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@ -188,7 +193,7 @@ func PrefetchSources(xTransport *XTransport, sources []*Source) time.Duration {
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continue
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}
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dlog.Debugf("Prefetching [%s]", u)
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_, _, delay, err := source.fetchWithCache(xTransport, u)
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delay, err := source.fetchWithCache(xTransport, u)
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if err != nil {
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dlog.Debugf("Prefetching [%s] failed: %v", u, err)
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continue
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@ -197,32 +197,32 @@ func setupSourceTest(t *testing.T) (func(), *SourceTestData) {
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d.cacheTests = map[string]SourceTestState{ // determines cache files written to disk before each call
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"correct": TestStateCorrect,
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//"expired": TestStateExpired, // TODO: an expired cache should be used if no download passes signature verification
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//"partial": TestStatePartial, // TODO: failed signature verification should not abort before trying additional URLs
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//"partial-sig": TestStatePartialSig, // TODO: failed signature verification should not abort before trying additional URLs
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"missing": TestStateMissing,
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//"missing-sig": TestStateMissingSig, // TODO: a cache without a signature should cause an attempt to download both files (not just the signature)
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"open-err": TestStateOpenErr,
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//"open-sig-err": TestStateOpenSigErr, // TODO: a cache without a signature should cause an attempt to download both files (not just the signature)
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"partial": TestStatePartial,
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"partial-sig": TestStatePartialSig,
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"missing": TestStateMissing,
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"missing-sig": TestStateMissingSig,
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"open-err": TestStateOpenErr,
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"open-sig-err": TestStateOpenSigErr,
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}
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d.downloadTests = map[string][]SourceTestState{ // determines the list of URLs passed in each call and how they will respond
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"correct": {TestStateCorrect},
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//"partial": {TestStatePartial}, // TODO: failed signature verification should not count as successfully prefetched
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//"partial-sig": {TestStatePartialSig}, // TODO: failed signature verification should not count as successfully prefetched
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"missing": {TestStateMissing},
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//"missing-sig": {TestStateMissingSig}, // TODO: failed signature verification should not count as successfully prefetched
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"read-err": {TestStateReadErr},
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//"read-sig-err": {TestStateReadSigErr}, // TODO: failed signature verification should not count as successfully prefetched
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"open-err": {TestStateOpenErr},
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//"open-sig-err": {TestStateOpenSigErr}, // TODO: failed signature verification should not count as successfully prefetched
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"correct": {TestStateCorrect},
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"partial": {TestStatePartial},
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"partial-sig": {TestStatePartialSig},
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"missing": {TestStateMissing},
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"missing-sig": {TestStateMissingSig},
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"read-err": {TestStateReadErr},
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"read-sig-err": {TestStateReadSigErr},
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"open-err": {TestStateOpenErr},
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"open-sig-err": {TestStateOpenSigErr},
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//"path-err": {TestStatePathErr}, // TODO: invalid URLs should not be included in the prefetch list
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//"partial,correct": {TestStatePartial, TestStateCorrect}, // TODO: all URLs should be included in the prefetch list, failed signature verification should not abort before trying additional URLs
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//"partial-sig,correct": {TestStatePartialSig, TestStateCorrect}, // TODO: all URLs should be included in the prefetch list, failed signature verification should not abort before trying additional URLs
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//"missing,correct": {TestStateMissing, TestStateCorrect}, // TODO: all URLs should be included in the prefetch list
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//"missing-sig,correct": {TestStateMissingSig, TestStateCorrect}, // TODO: all URLs should be included in the prefetch list, failed signature verification should not abort before trying additional URLs
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//"read-err,correct": {TestStateReadErr, TestStateCorrect}, // TODO: all URLs should be included in the prefetch list
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//"read-sig-err,correct": {TestStateReadSigErr, TestStateCorrect}, // TODO: all URLs should be included in the prefetch list, failed signature verification should not abort before trying additional URLs
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//"open-err,correct": {TestStateOpenErr, TestStateCorrect}, // TODO: all URLs should be included in the prefetch list
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//"open-sig-err,correct": {TestStateOpenSigErr, TestStateCorrect}, // TODO: all URLs should be included in the prefetch list, failed signature verification should not abort before trying additional URLs
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"partial,correct": {TestStatePartial, TestStateCorrect},
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"partial-sig,correct": {TestStatePartialSig, TestStateCorrect},
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"missing,correct": {TestStateMissing, TestStateCorrect},
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"missing-sig,correct": {TestStateMissingSig, TestStateCorrect},
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"read-err,correct": {TestStateReadErr, TestStateCorrect},
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"read-sig-err,correct": {TestStateReadSigErr, TestStateCorrect},
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"open-err,correct": {TestStateOpenErr, TestStateCorrect},
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"open-sig-err,correct": {TestStateOpenSigErr, TestStateCorrect},
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//"path-err,correct": {TestStatePathErr, TestStateCorrect}, // TODO: invalid URLs should not be included in the prefetch list
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"no-urls": {},
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}
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@ -252,7 +252,7 @@ func prepSourceTestCache(t *testing.T, d *SourceTestData, e *SourceTestExpect, s
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case TestStatePartial, TestStatePartialSig:
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e.err = "signature"
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case TestStateMissing, TestStateMissingSig:
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e.err = "stat"
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e.err = "open"
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case TestStateOpenErr, TestStateOpenSigErr:
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e.err = os.ErrPermission.Error()
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}
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