view tests/test-strip-cross.t @ 30766:d7bf7d2bd5ab

hgweb: support Content Security Policy

Content-Security-Policy (CSP) is a web security feature that allows
servers to declare what loaded content is allowed to do. For example,
a policy can prevent loading of images, JavaScript, CSS, etc unless
the source of that content is whitelisted (by hostname, URI scheme,
hashes of content, etc). It's a nifty security feature that provides
extra mitigation against some attacks, notably XSS.

Mitigation against these attacks is important for Mercurial because
hgweb renders repository data, which is commonly untrusted. While we
make attempts to escape things, etc, there's the possibility that
malicious data could be injected into the site content. If this happens
today, the full power of the web browser is available to that
malicious content. A restrictive CSP policy (defined by the server
operator and sent in an HTTP header which is outside the control of
malicious content), could restrict browser capabilities and mitigate
security problems posed by malicious data.

CSP works by emitting an HTTP header declaring the policy that browsers
should apply. Ideally, this header would be emitted by a layer above
Mercurial (likely the HTTP server doing the WSGI "proxying"). This
works for some CSP policies, but not all.

For example, policies to allow inline JavaScript may require setting
a "nonce" attribute on <script>. This attribute value must be unique
and non-guessable. And, the value must be present in the HTTP header
and the HTML body. This means that coordinating the value between
Mercurial and another HTTP server could be difficult: it is much
easier to generate and emit the nonce in a central location.

This commit introduces support for emitting a
Content-Security-Policy header from hgweb. A config option defines
the header value. If present, the header is emitted. A special
"%nonce%" syntax in the value triggers generation of a nonce and
inclusion in <script> elements in templates. The inclusion of a
nonce does not occur unless "%nonce%" is present. This makes this
commit completely backwards compatible and the feature opt-in.

The nonce is a type 4 UUID, which is the flavor that is randomly
generated. It has 122 random bits, which should be plenty to satisfy
the guarantees of a nonce.

test stripping of filelogs where the linkrev doesn't always increase

  $ echo '[extensions]' >> $HGRCPATH
  $ echo 'strip =' >> $HGRCPATH
  $ hg init orig
  $ cd orig
  $ commit()
  > {
  >     hg up -qC null
  >     count=1
  >     for i in "$@"; do
  >         for f in $i; do
  >             echo $count > $f
  >         done
  >         count=`expr $count + 1`
  >     done
  >     hg commit -qAm "$*"
  > }

2 1 0 2 0 1 2

  $ commit '201 210'
  $ commit '102 120' '210'
  $ commit '021'
  $ commit '201' '021 120'
  $ commit '012 021' '102 201' '120 210'
  $ commit 'manifest-file'
  $ commit '102 120' '012 210' '021 201'
  $ commit '201 210' '021 120' '012 102'
  $ HGUSER=another-user; export HGUSER
  $ commit 'manifest-file'
  $ commit '012' 'manifest-file'
  $ cd ..
  $ hg clone -q -U -r -1 -r -2 -r -3 -r -4 -r -6 orig crossed
  $ cd crossed
  $ hg debugindex --manifest
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0     112  .....       0 6f105cbb914d 000000000000 000000000000 (re)
       1       112      56  .....       3 1b55917b3699 000000000000 000000000000 (re)
       2       168     123  .....       1 8f3d04e263e5 000000000000 000000000000 (re)
       3       291     122  .....       2 f0ef8726ac4f 000000000000 000000000000 (re)
       4       413      87  .....       4 0b76e38b4070 000000000000 000000000000 (re)

  $ for i in 012 021 102 120 201 210 manifest-file; do
  >     echo $i
  >     hg debugindex $i
  >     echo
  > done
  012
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       0 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       1 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       2 2661d26c6496 000000000000 000000000000 (re)
  
  021
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       0 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       2 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       1 2661d26c6496 000000000000 000000000000 (re)
  
  102
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       1 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       0 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       2 2661d26c6496 000000000000 000000000000 (re)
  
  120
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       1 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       2 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       0 2661d26c6496 000000000000 000000000000 (re)
  
  201
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       2 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       0 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       1 2661d26c6496 000000000000 000000000000 (re)
  
  210
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       2 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       1 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       0 2661d26c6496 000000000000 000000000000 (re)
  
  manifest-file
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       3 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       4 5d9299349fc0 000000000000 000000000000 (re)
  
  $ cd ..
  $ for i in 0 1 2 3 4; do
  >     hg clone -q -U --pull crossed $i
  >     echo "% Trying to strip revision $i"
  >     hg --cwd $i strip $i
  >     echo "% Verifying"
  >     hg --cwd $i verify
  >     echo
  > done
  % Trying to strip revision 0
  saved backup bundle to $TESTTMP/0/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 15 total revisions
  
  % Trying to strip revision 1
  saved backup bundle to $TESTTMP/1/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 14 total revisions
  
  % Trying to strip revision 2
  saved backup bundle to $TESTTMP/2/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 14 total revisions
  
  % Trying to strip revision 3
  saved backup bundle to $TESTTMP/3/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 19 total revisions
  
  % Trying to strip revision 4
  saved backup bundle to $TESTTMP/4/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 19 total revisions