[PATCH/RFC] gitweb: highlight: strip non-printable characters via col(1)

["Christopher M. Fuhrman" <cfuhrman@panix.com>]

From: "Christopher M. Fuhrman" <cfuhrman@panix.com>

The current code, as is, passes control characters, such as form-feed
(^L) to highlight which then passes it through to the browser.  This
will cause the browser to display one of the following warnings:

Safari v5.1 (6534.50) & Google Chrome v13.0.782.112:

  This page contains the following errors:

  error on line 657 at column 38: PCDATA invalid Char value 12
  Below is a rendering of the page up to the first error.

Mozilla Firefox 3.6.19 & Mozilla Firefox 5.0:

   XML Parsing Error: not well-formed
   Location:
   http://path/to/git/repo/blah/blah

Both errors were generated by gitweb.perl v1.7.3.4 w/ highlight 2.7
using arch/ia64/kernel/unwind.c from the Linux kernel.

Strip non-printable control-characters by piping the output produced
by git-cat-file(1) to col(1) as follows:

  git cat-file blob deadbeef314159 | col -bx | highlight <args>

Tested under OpenSuSE 11.4 & NetBSD 5.1 using perl 5.12.3 and perl
5.12.2 respectively using Safari, Firefox, and Google Chrome.

Signed-off-by: Christopher M. Fuhrman <cfuhrman@panix.com>
---

For an example of this bug in action, see:

 *
   http://git.fuhrbear.com/~cfuhrman/?p=linux/.git;a=blob;f=arch/alpha/kernel/core_titan.c;h=219bf271c0ba2e5f2d668af707df57fbbd00ccfd;hb=HEAD
 *
   http://git.fuhrbear.com/~cfuhrman/?p=linux/.git;a=blob;f=arch/ia64/kernel/unwind.c;h=fed6afa2e8a9014e65229e51e64fa4b1c13cc284;hb=HEAD

WRT the col(1) command, I've verified that the binary is installed in
/usr/bin on OpenSuSE, NetBSD, OpenBSD, Solaris 10, and AIX.  This
patch assumes that /usr/bin is in $PATH.

Cheers!

 gitweb/gitweb.perl |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 81dacf2..38d5d4e 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -3656,6 +3656,7 @@ sub run_highlighter {
 
 	close $fd;
 	open $fd, quote_command(git_cmd(), "cat-file", "blob", $hash)." | ".
+	          "col -bx | ".
 	          quote_command($highlight_bin).
 	          " --replace-tabs=8 --fragment --syntax $syntax |"
 		or die_error(500, "Couldn't open file or run syntax highlighter");
-- 
1.7.5.4