[PATCH 3 of 6 V2] hgweb: restrict usage of regular expressions in search

[Alexander Plavin]

# HG changeset patch
# User Alexander Plavin <alexander at plav.in>
# Date 1376650882 -14400
#      Fri Aug 16 15:01:22 2013 +0400
# Node ID 3a09bc2bf256789aa7a4d5c50dedf9fb50886873
# Parent  d7684354b9a2755149fc8b9740d2770634d3185e
hgweb: restrict usage of regular expressions in search

If the search query has strings defining revset regular expressions
(those starting with 're:'), revset syntax is disabled. It eliminates the
possibility of ReDoS.

diff -r d7684354b9a2 -r 3a09bc2bf256 mercurial/hgweb/webcommands.py
--- a/mercurial/hgweb/webcommands.py	Wed Aug 07 01:16:14 2013 +0400
+++ b/mercurial/hgweb/webcommands.py	Fri Aug 16 15:01:22 2013 +0400
@@ -175,6 +175,10 @@
             # no revset syntax used
             return 'kw'
 
+        if any((token, (value or '')[:3]) == ('string', 're:')
+               for token, value, pos in revset.tokenize(revdef)):
+            return 'kw'
+
         mfunc = revset.match(None, revdef)
         try:
             # try running against empty subset
diff -r d7684354b9a2 -r 3a09bc2bf256 tests/test-hgweb-commands.t
--- a/tests/test-hgweb-commands.t	Wed Aug 07 01:16:14 2013 +0400
+++ b/tests/test-hgweb-commands.t	Fri Aug 16 15:01:22 2013 +0400
@@ -632,6 +632,56 @@
   
   
 
+  $ "$TESTDIR/get-with-headers.py" 127.0.0.1:$HGPORT 'log?rev=user("test")&style=raw'
+  200 Script output follows
+  
+  
+  # HG changesets search
+  # Node ID cad8025a2e87f88c06259790adfa15acb4080123
+  # Query "user("test")"
+  
+  changeset:   cad8025a2e87f88c06259790adfa15acb4080123
+  revision:    3
+  user:        test
+  date:        Thu, 01 Jan 1970 00:00:00 +0000
+  summary:     branch commit with null character: \x00 (esc)
+  branch:      unstable
+  tag:         tip
+  bookmark:    something
+  
+  changeset:   1d22e65f027e5a0609357e7d8e7508cd2ba5d2fe
+  revision:    2
+  user:        test
+  date:        Thu, 01 Jan 1970 00:00:00 +0000
+  summary:     branch
+  branch:      stable
+  
+  changeset:   a4f92ed23982be056b9852de5dfe873eaac7f0de
+  revision:    1
+  user:        test
+  date:        Thu, 01 Jan 1970 00:00:00 +0000
+  summary:     Added tag 1.0 for changeset 2ef0ac749a14
+  branch:      default
+  
+  changeset:   2ef0ac749a14e4f57a5a822464a0902c6f7f448f
+  revision:    0
+  user:        test
+  date:        Thu, 01 Jan 1970 00:00:00 +0000
+  summary:     base
+  tag:         1.0
+  bookmark:    anotherthing
+  
+  
+  $ "$TESTDIR/get-with-headers.py" 127.0.0.1:$HGPORT 'log?rev=user("re:test")&style=raw'
+  200 Script output follows
+  
+  
+  # HG changesets search
+  # Node ID cad8025a2e87f88c06259790adfa15acb4080123
+  # Query "user("re:test")"
+  
+  
+
 File-related
 
   $ "$TESTDIR/get-with-headers.py" 127.0.0.1:$HGPORT 'file/1/foo/?style=raw'