procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
#require serve
$ cat > web.conf << EOF
> [paths]
> / = $TESTTMP/*
> EOF
$ hg init repo1
$ cd repo1
$ touch foo
$ hg -q commit -A -m initial
$ cd ..
$ hg serve -p $HGPORT -d --pid-file=hg.pid --web-conf web.conf
$ cat hg.pid >> $DAEMON_PIDS
repo index should not send Content-Security-Policy header by default
$ get-with-headers.py --headeronly localhost:$HGPORT '' content-security-policy etag
200 Script output follows
static page should not send CSP by default
$ get-with-headers.py --headeronly localhost:$HGPORT static/mercurial.js content-security-policy etag
200 Script output follows
repo page should not send CSP by default, should send ETag
$ get-with-headers.py --headeronly localhost:$HGPORT repo1 content-security-policy etag
200 Script output follows
etag: W/"*" (glob)
$ killdaemons.py
Configure CSP without nonce
$ cat >> web.conf << EOF
> [web]
> csp = script-src https://example.com/ 'unsafe-inline'
> EOF
$ hg serve -p $HGPORT -d --pid-file=hg.pid --web-conf web.conf
$ cat hg.pid > $DAEMON_PIDS
repo index should send Content-Security-Policy header when enabled
$ get-with-headers.py --headeronly localhost:$HGPORT '' content-security-policy etag
200 Script output follows
content-security-policy: script-src https://example.com/ 'unsafe-inline'
static page should send CSP when enabled
$ get-with-headers.py --headeronly localhost:$HGPORT static/mercurial.js content-security-policy etag
200 Script output follows
content-security-policy: script-src https://example.com/ 'unsafe-inline'
$ get-with-headers.py --twice --headeronly localhost:$HGPORT repo1/static/style.css content-security-policy
200 Script output follows
content-security-policy: script-src https://example.com/ 'unsafe-inline'
304 Not Modified
content-security-policy: script-src https://example.com/ 'unsafe-inline'
repo page should send CSP by default, include etag w/o nonce
$ get-with-headers.py --headeronly localhost:$HGPORT repo1 content-security-policy etag
200 Script output follows
content-security-policy: script-src https://example.com/ 'unsafe-inline'
etag: W/"*" (glob)
nonce should not be added to html if CSP doesn't use it
$ get-with-headers.py localhost:$HGPORT repo1/graph/tip | egrep 'content-security-policy|<script'
<script type="text/javascript" src="/repo1/static/mercurial.js"></script>
<script type="text/javascript">
<script type="text/javascript">
Configure CSP with nonce
$ killdaemons.py
$ cat >> web.conf << EOF
> csp = image-src 'self'; script-src https://example.com/ 'nonce-%nonce%'
> EOF
$ hg serve -p $HGPORT -d --pid-file=hg.pid --web-conf web.conf
$ cat hg.pid > $DAEMON_PIDS
nonce should be substituted in CSP header
$ get-with-headers.py --headeronly localhost:$HGPORT '' content-security-policy etag
200 Script output follows
content-security-policy: image-src 'self'; script-src https://example.com/ 'nonce-*' (glob)
nonce should be included in CSP for static pages
$ get-with-headers.py --headeronly localhost:$HGPORT static/mercurial.js content-security-policy etag
200 Script output follows
content-security-policy: image-src 'self'; script-src https://example.com/ 'nonce-*' (glob)
repo page should have nonce, no ETag
$ get-with-headers.py --headeronly localhost:$HGPORT repo1 content-security-policy etag
200 Script output follows
content-security-policy: image-src 'self'; script-src https://example.com/ 'nonce-*' (glob)
nonce should be added to html when used
$ get-with-headers.py localhost:$HGPORT repo1/graph/tip content-security-policy | egrep 'content-security-policy|<script'
content-security-policy: image-src 'self'; script-src https://example.com/ 'nonce-*' (glob)
<script type="text/javascript" src="/repo1/static/mercurial.js"></script>
<script type="text/javascript" nonce="*"> (glob)
<script type="text/javascript" nonce="*"> (glob)
hgweb_mod w/o hgwebdir works as expected
$ killdaemons.py
$ hg serve -R repo1 -p $HGPORT -d --pid-file=hg.pid --config "web.csp=image-src 'self'; script-src https://example.com/ 'nonce-%nonce%'"
$ cat hg.pid > $DAEMON_PIDS
static page sends CSP
$ get-with-headers.py --headeronly localhost:$HGPORT static/mercurial.js content-security-policy etag
200 Script output follows
content-security-policy: image-src 'self'; script-src https://example.com/ 'nonce-*' (glob)
nonce included in <script> and headers
$ get-with-headers.py localhost:$HGPORT graph/tip content-security-policy | egrep 'content-security-policy|<script'
content-security-policy: image-src 'self'; script-src https://example.com/ 'nonce-*' (glob)
<script type="text/javascript" src="/static/mercurial.js"></script>
<script type="text/javascript" nonce="*"> (glob)
<script type="text/javascript" nonce="*"> (glob)