ugh

[ikiwiki.git] / doc / security.mdwn

diff --git a/doc/security.mdwn b/doc/security.mdwn
index 0731ff3c5794cfe7b16f64286e1481c3d74ac836..c7a6fcd69dd0d91df051d793ce2d1a0bd2299a52 100644 (file)
--- a/doc/security.mdwn
+++ b/doc/security.mdwn
@@ -44,12 +44,19 @@ this wiki, BTW.
 
 ## svn commit logs
 
 
 ## svn commit logs
 

-Anyone with svn commit access can forge "web commit from foo" and make it appeat on [[RecentChanges]] like foo committed. One way to avoid this would be to limit web commits to those done by a certian user.
+Anyone with svn commit access can forge "web commit from foo" and make it appear on [[RecentChanges]] like foo committed. One way to avoid this would be to limit web commits to those done by a certian user.

 
 It's actually possible to force a whole series of svn commits to appear to have come just before yours, by forging svn log output. This could be guarded against somewhat by revision number scanning, since the forged revisions would duplicate the numbers of unforged ones. Or subversion could fix svn log to indent commit messages, which would make such forgery impossible..
 
 ikiwiki escapes any html in svn commit logs to prevent other mischief.
 
 
 It's actually possible to force a whole series of svn commits to appear to have come just before yours, by forging svn log output. This could be guarded against somewhat by revision number scanning, since the forged revisions would duplicate the numbers of unforged ones. Or subversion could fix svn log to indent commit messages, which would make such forgery impossible..
 
 ikiwiki escapes any html in svn commit logs to prevent other mischief.
 

+## page locking can be bypassed via direct svn commits
+
+A [[lock]]ed page can only be edited on the web by an admin, but
+anyone who is allowed to commit direct to svn can bypass this. This is by
+design, although a subversion pre-commit hook could be used to prevent
+editing of locked pages when using subversion, if you really need to.
+

 ----
 
 # Hopefully non-holes
 ----
 
 # Hopefully non-holes


@@ -84,7 +91,7 @@ been no problem yet.
 
 ikiwiki does not expose untrusted data to the shell. In fact it doesn't use
 system() at all, and the only use of backticks is on data supplied by the
 
 ikiwiki does not expose untrusted data to the shell. In fact it doesn't use
 system() at all, and the only use of backticks is on data supplied by the

-wiki admin. And it runs with taint checks on of course..
+wiki admin and untainted filenames. And it runs with taint checks on of course..

 
 ## cgi data security
 
 
 ## cgi data security
 


@@ -109,7 +116,9 @@ Login to the wiki involves sending a password in cleartext over the net.
 Cracking the password only allows editing the wiki as that user though.
 If you care, you can use https, I suppose.
 
 Cracking the password only allows editing the wiki as that user though.
 If you care, you can use https, I suppose.
 

-# Fixed holes.
+# Fixed holes
+
+_(Unless otherwise noted, these were discovered and immediatey fixed by the ikiwiki developers.)_

 
 ## destination directory file replacement
 
 
 ## destination directory file replacement
 


@@ -132,6 +141,22 @@ into the repo. ikiwiki uses File::Find to traverse the repo, and does not
 tell it to follow symlinks, but it might be possible to race replacing a
 directory with a symlink and trick it into following the link.
 
 tell it to follow symlinks, but it might be possible to race replacing a
 directory with a symlink and trick it into following the link.
 

-Also, if someone checks in a symlink to /etc/passwd, ikiwiki would read and publish that, which could be used to expose files a committer otherwise wouldn't see.
+Also, if someone checks in a symlink to /etc/passwd, ikiwiki would read and
+publish that, which could be used to expose files a committer otherwise
+wouldn't see.
+
+To avoid this, ikiwiki will skip over symlinks when scanning for pages, and
+uses locking to prevent more than one instance running at a time. The lock
+prevents one ikiwiki from running a svn up at the wrong time to race
+another ikiwiki. So only attackers who can write to the working copy on
+their own can race it.
+
+## symlink + cgi attacks
+
+Similarly, a svn commit of a symlink could be made, ikiwiki ignores it
+because of the above, but the symlink is still there, and then you edit the
+page from the web, which follows the symlink when reading the page, and
+again when saving the changed page.

 
 

-To avoid this, ikiwiki will avoid reading files that are symlinks, and uses locking to prevent more than one instance running at a time. The lock prevents one ikiwiki from running a svn up at the wrong time to race another ikiwiki. So only attackers who can write to the working copy on their own can race it.
\ No newline at end of file
+This was fixed by making ikiwiki refuse to read or write to files that are
+symlinks, combined with the above locking.