view tests/test-diff-unified.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.

  $ hg init repo
  $ cd repo
  $ cat > a <<EOF
  > c
  > c
  > a
  > a
  > b
  > a
  > a
  > c
  > c
  > EOF
  $ hg ci -Am adda
  adding a

  $ cat > a <<EOF
  > c
  > c
  > a
  > a
  > dd
  > a
  > a
  > c
  > c
  > EOF

default context

  $ hg diff --nodates
  diff -r cf9f4ba66af2 a
  --- a/a
  +++ b/a
  @@ -2,7 +2,7 @@
   c
   a
   a
  -b
  +dd
   a
   a
   c

invalid --unified

  $ hg diff --nodates -U foo
  abort: diff context lines count must be an integer, not 'foo'
  [255]


  $ hg diff --nodates -U 2
  diff -r cf9f4ba66af2 a
  --- a/a
  +++ b/a
  @@ -3,5 +3,5 @@
   a
   a
  -b
  +dd
   a
   a

  $ hg --config diff.unified=2 diff --nodates
  diff -r cf9f4ba66af2 a
  --- a/a
  +++ b/a
  @@ -3,5 +3,5 @@
   a
   a
  -b
  +dd
   a
   a

  $ hg diff --nodates -U 1
  diff -r cf9f4ba66af2 a
  --- a/a
  +++ b/a
  @@ -4,3 +4,3 @@
   a
  -b
  +dd
   a

invalid diff.unified

  $ hg --config diff.unified=foo diff --nodates
  abort: diff context lines count must be an integer, not 'foo'
  [255]

noprefix config and option

  $ hg --config diff.noprefix=True diff --nodates
  diff -r cf9f4ba66af2 a
  --- a
  +++ a
  @@ -2,7 +2,7 @@
   c
   a
   a
  -b
  +dd
   a
   a
   c
  $ hg diff --noprefix --nodates
  diff -r cf9f4ba66af2 a
  --- a
  +++ a
  @@ -2,7 +2,7 @@
   c
   a
   a
  -b
  +dd
   a
   a
   c

noprefix config disabled in plain mode, but option still enabled

  $ HGPLAIN=1 hg --config diff.noprefix=True diff --nodates
  diff -r cf9f4ba66af2 a
  --- a/a
  +++ b/a
  @@ -2,7 +2,7 @@
   c
   a
   a
  -b
  +dd
   a
   a
   c
  $ HGPLAIN=1 hg diff --noprefix --nodates
  diff -r cf9f4ba66af2 a
  --- a
  +++ a
  @@ -2,7 +2,7 @@
   c
   a
   a
  -b
  +dd
   a
   a
   c

  $ cd ..


0 lines of context hunk header matches gnu diff hunk header

  $ hg init diffzero
  $ cd diffzero
  $ cat > f1 << EOF
  > c2
  > c4
  > c5
  > EOF
  $ hg commit -Am0
  adding f1

  $ cat > f2 << EOF
  > c1
  > c2
  > c3
  > c4
  > EOF
  $ mv f2 f1
  $ hg diff -U0 --nodates
  diff -r 55d8ff78db23 f1
  --- a/f1
  +++ b/f1
  @@ -0,0 +1,1 @@
  +c1
  @@ -1,0 +3,1 @@
  +c3
  @@ -3,1 +4,0 @@
  -c5

  $ hg diff -U0 --nodates --git
  diff --git a/f1 b/f1
  --- a/f1
  +++ b/f1
  @@ -0,0 +1,1 @@
  +c1
  @@ -1,0 +3,1 @@
  +c3
  @@ -3,1 +4,0 @@
  -c5

  $ hg diff -U0 --nodates -p
  diff -r 55d8ff78db23 f1
  --- a/f1
  +++ b/f1
  @@ -0,0 +1,1 @@
  +c1
  @@ -1,0 +3,1 @@ c2
  +c3
  @@ -3,1 +4,0 @@ c4
  -c5

  $ echo a > f1
  $ hg ci -m movef2

Test diff headers terminating with TAB when necessary (issue3357)
Regular diff --nodates, file creation

  $ hg mv f1 'f 1'
  $ echo b > 'f 1'
  $ hg diff --nodates 'f 1'
  diff -r 7574207d0d15 f 1
  --- /dev/null
  +++ b/f 1	
  @@ -0,0 +1,1 @@
  +b

Git diff, adding space

  $ hg diff --git
  diff --git a/f1 b/f 1
  rename from f1
  rename to f 1
  --- a/f1
  +++ b/f 1	
  @@ -1,1 +1,1 @@
  -a
  +b

Git diff with noprefix

  $ hg --config diff.noprefix=True diff --git --nodates
  diff --git f1 f 1
  rename from f1
  rename to f 1
  --- f1
  +++ f 1	
  @@ -1,1 +1,1 @@
  -a
  +b

noprefix config disabled in plain mode, but option still enabled

  $ HGPLAIN=1 hg --config diff.noprefix=True diff --git --nodates
  diff --git a/f1 b/f 1
  rename from f1
  rename to f 1
  --- a/f1
  +++ b/f 1	
  @@ -1,1 +1,1 @@
  -a
  +b
  $ HGPLAIN=1 hg diff --git --noprefix --nodates
  diff --git f1 f 1
  rename from f1
  rename to f 1
  --- f1
  +++ f 1	
  @@ -1,1 +1,1 @@
  -a
  +b

Regular diff --nodates, file deletion

  $ hg ci -m addspace
  $ hg mv 'f 1' f1
  $ echo a > f1
  $ hg diff --nodates 'f 1'
  diff -r ca50fe67c9c7 f 1
  --- a/f 1	
  +++ /dev/null
  @@ -1,1 +0,0 @@
  -b

Git diff, removing space

  $ hg diff --git
  diff --git a/f 1 b/f1
  rename from f 1
  rename to f1
  --- a/f 1	
  +++ b/f1
  @@ -1,1 +1,1 @@
  -b
  +a

showfunc diff
  $ cat > f1 << EOF
  > int main() {
  >     int a = 0;
  >     int b = 1;
  >     int c = 2;
  >     int d = 3;
  >     return a + b + c + d;
  > }
  > EOF
  $ hg commit -m addfunction
  $ cat > f1 << EOF
  > int main() {
  >     int a = 0;
  >     int b = 1;
  >     int c = 2;
  >     int e = 3;
  >     return a + b + c + e;
  > }
  > EOF
  $ hg diff --git
  diff --git a/f1 b/f1
  --- a/f1
  +++ b/f1
  @@ -2,6 +2,6 @@
       int a = 0;
       int b = 1;
       int c = 2;
  -    int d = 3;
  -    return a + b + c + d;
  +    int e = 3;
  +    return a + b + c + e;
   }
  $ hg diff --config diff.showfunc=True --git
  diff --git a/f1 b/f1
  --- a/f1
  +++ b/f1
  @@ -2,6 +2,6 @@ int main() {
       int a = 0;
       int b = 1;
       int c = 2;
  -    int d = 3;
  -    return a + b + c + d;
  +    int e = 3;
  +    return a + b + c + e;
   }

If [diff] git is set to true, but the user says --no-git, we should
*not* get git diffs
  $ hg diff --nodates --config diff.git=1 --no-git
  diff -r f2c7c817fa55 f1
  --- a/f1
  +++ b/f1
  @@ -2,6 +2,6 @@
       int a = 0;
       int b = 1;
       int c = 2;
  -    int d = 3;
  -    return a + b + c + d;
  +    int e = 3;
  +    return a + b + c + e;
   }

  $ cd ..