X-Git-Url: https://sipb.mit.edu/gitweb.cgi/ikiwiki.git/blobdiff_plain/73e562edc865c6357cc1b4c8436e0a44957800e8..8c55424b11edbe1fd3e6ff1e20ec85c1f3c6e593:/doc/plugins/contrib/cvs/discussion.mdwn

diff --git a/doc/plugins/contrib/cvs/discussion.mdwn b/doc/plugins/contrib/cvs/discussion.mdwn
index ed6cf506e..1f0ce0102 100644
--- a/doc/plugins/contrib/cvs/discussion.mdwn
+++ b/doc/plugins/contrib/cvs/discussion.mdwn
@@ -24,6 +24,38 @@ the "cvs add <directory>" call and avoid doing anything in that case?
 >> It seems like it might be. You can use a `getopt` hook to check
 >> `@ARGV` to see how it was called. --[[Joey]] 
 
+>>> This does the trick iff the post-commit wrapper passes its args
+>>> along. Committed on my branch. This seems potentially dangerous,
+>>> since the args passed to ikiwiki are influenced by web commits.
+>>> I don't see an exploit, but for paranoia's sake, maybe the wrapper
+>>> should only be built with execv() if the cvs plugin is loaded?
+>>> --[[schmonz]]
+
+>>>> Hadn't considered that. While in wrapper mode the normal getopt is not
+>>>> done, plugin getopt still runs, and so any unsafe options that 
+>>>> other plugins support could be a problem if another user runs
+>>>> the setuid wrapper and passes those options through. --[[Joey]]
+
+>>>>> I've tried compiling the argument check into the wrapper as
+>>>>> the first thing main() does, and was surprised to find that
+>>>>> this doesn't prevent the `cvs add <dir>` deadlock in a web
+>>>>> commit. I was convinced this'd be a reasonable solution,
+>>>>> especially if conditionalized on the cvs plugin being loaded,
+>>>>> but it doesn't work. And I stuck debug printfs at the beginning
+>>>>> of all the rcs_foo() subs, and whatever `cvs add <dir>` is
+>>>>> doing to ikiwiki isn't visible to my plugin, because none of
+>>>>> those subs are getting called. Nuts. Can you think of anything
+>>>>> else that might solve the problem, or should I go back to
+>>>>> generating a minimal wrapper wrapper that checks for just
+>>>>> this one thing? --[[schmonz]]
+
+>>>>>> I don't see how there could possibly be a difference between
+>>>>>> ikiwiki's C wrapper and your shell wrapper wrapper here. --[[Joey]]
+
+>>>>>>> I was comparing strings overly precisely. Fixed on my branch.
+>>>>>>> I've also knocked off the two most pressing to-do items. I
+>>>>>>> think the plugin's ready for prime time. --[[schmonz]]
+
 > Thing 2 I'm less sure of. (I'd like to see the web UI return
 > immediately on save anyway, to a temporary "rebuilding, please wait
 > if you feel like knowing when it's done" page, but this problem
@@ -42,6 +74,9 @@ the "cvs add <directory>" call and avoid doing anything in that case?
 >> on a " &" to the ikiwiki wrapper call doesn't need a wrapper script,
 >> does it? --[[Joey]]
 
+>>> Nope, it works fine to append it to the `CVSROOT/loginfo` line.
+>>> Fixed on my branch. --[[schmonz]]
+
 > Thing 3 I think I did in order to squelch the error messages that
 > were bollixing up the CGI. It was easy to do this in the wrapper
 > wrapper, but if that's going away, it can be done just as easily
@@ -51,3 +86,42 @@ the "cvs add <directory>" call and avoid doing anything in that case?
 
 >> If the error messages screw up the CGI they must go to stdout.
 >> I thought we had stderr even in the the CVS dark ages. ;-) --[[Joey]] 
+
+>>> Some messages go to stderr, but definitely not all. That's why
+>>> I wound up reaching for IPC::Cmd, to execute the command line
+>>> safely while shutting CVS up. Anyway, I've tested what happens
+>>> if a configured post-commit hook is missing, and it seems fine,
+>>> probably also thanks to IPC::Cmd.
+>>> --[[schmonz]]
+
+----
+
+
+Further review.. --[[Joey]] 
+
+I don't understand what `cvs_shquote_commit` is
+trying to do with the test message, but it seems
+highly likely to be insecure; I never trust anything 
+that relies on safely quoting user input passed to the shell. 
+
+(As an aside, `shell_quote` can die on certian inputs.)
+
+Seems to me that, if `IPC::Cmd` exposes input to the shell
+(which I have not verified but its docs don't specify; a bad sign)
+you chose the wrong tool and ended up doing down the wrong
+route, dragging in shell quoting problems and fixes. Since you
+chose to use `IPC::Cmd`	just because you wanted to shut
+up CVS stderr, my suggestion would be to use plain `system`
+to run the command, with stderr temporarily sent to /dev/null:
+
+	open(my $savederr, ">&STDERR");
+	open(STDERR, ">", "/dev/null");
+	my $ret=system("cvs", "-Q", @_);
+	open(STDERR, ">$savederr");
+
+`cvs_runcvs` should not take an array reference. It's
+usual for this type of function to take a list of parameters
+to pass to the command.
+
+> Thanks for reading carefully. I've tested your suggestions and
+> applied them on my branch. --[[schmonz]]