scan-tree: Support gitweb.description.

Use gitweb.description instead of description file to determine
description, if option is enabled.
scan-tree: Support gitweb.category.

Use gitweb.category from git config to determine repo's section, if
option is enabled.
ui-repolist: Case insensitive sorting and age sort

Add two options, one for doing the ordinary name sorts in a
case-insensitive manner, and another for choosing to sort repos in each
section by age instead of by name.
Update copyright headers to have latest dates.
ui-snapshot: pass -n to gzip, to suppress timestamp

Since cgit snapshots of tags are often used for releases, we don't
want the rarely used feature of the gzip compressor that includes
an embedded timestamp into the archive, since this makes each tarball
of the same (potentially signed) tag different.

This commit refactors the archive handling code a bit so that each
different format is able to run with an arbitrary argv for the filter.
do not write outside heap buffer

* parsing.c (substr): Handle tail < head.

This started when I noticed some cgit segfaults on savannah.gnu.org.
Finding the offending URL/commit and then constructing a stand-alone
reproducer were far more time-consuming than writing the actual patch.

The problem arises with a commit like this, in which the user name
part of the "Author" field is empty:

    $ git log -1
    commit 6f3f41d73393278f3ede68a2cb1e7a2a23fa3421
    Author: <T at h.or>
    Date:   Mon Apr 23 22:29:16 2012 +0200

Here's what happens:

(this is due to buf=malloc(0); strncpy (buf, head, -1);
 where "head" may point to plenty of attacker-specified non-NUL bytes,
 so we can overwrite a zero-length heap buffer with arbitrary data)

 Invalid write of size 1
    at 0x4A09361: strncpy (mc_replace_strmem.c:463)
    by 0x408977: substr (parsing.c:61)
    by 0x4089EF: parse_user (parsing.c:73)
    by 0x408D10: cgit_parse_commit (parsing.c:153)
    by 0x40A540: cgit_mk_refinfo (shared.c:171)
    by 0x40A581: cgit_refs_cb (shared.c:181)
    by 0x43DEB3: do_for_each_ref (refs.c:690)
    by 0x41075E: cgit_print_branches (ui-refs.c:191)
    by 0x416EF2: cgit_print_summary (ui-summary.c:56)
    by 0x40780A: summary_fn (cmd.c:120)
    by 0x40667A: process_request (cgit.c:544)
    by 0x404078: cache_process (cache.c:322)
  Address 0x4c718d0 is 0 bytes after a block of size 0 alloc'd
    at 0x4A0884D: malloc (vg_replace_malloc.c:263)
    by 0x455C85: xmalloc (wrapper.c:35)
    by 0x40894C: substr (parsing.c:60)
    by 0x4089EF: parse_user (parsing.c:73)
    by 0x408D10: cgit_parse_commit (parsing.c:153)
    by 0x40A540: cgit_mk_refinfo (shared.c:171)
    by 0x40A581: cgit_refs_cb (shared.c:181)
    by 0x43DEB3: do_for_each_ref (refs.c:690)
    by 0x41075E: cgit_print_branches (ui-refs.c:191)
    by 0x416EF2: cgit_print_summary (ui-summary.c:56)
    by 0x40780A: summary_fn (cmd.c:120)
    by 0x40667A: process_request (cgit.c:544)

 Invalid write of size 1
    at 0x4A09400: strncpy (mc_replace_strmem.c:463)
    by 0x408977: substr (parsing.c:61)
    by 0x4089EF: parse_user (parsing.c:73)
    by 0x408D10: cgit_parse_commit (parsing.c:153)
    by 0x40A540: cgit_mk_refinfo (shared.c:171)
    by 0x40A581: cgit_refs_cb (shared.c:181)
    by 0x43DEB3: do_for_each_ref (refs.c:690)
    by 0x41075E: cgit_print_branches (ui-refs.c:191)
    by 0x416EF2: cgit_print_summary (ui-summary.c:56)
    by 0x40780A: summary_fn (cmd.c:120)
    by 0x40667A: process_request (cgit.c:544)
    by 0x404078: cache_process (cache.c:322)
  Address 0x4c7192b is not stack'd, malloc'd or (recently) free'd

 Invalid write of size 1
    at 0x4A0940E: strncpy (mc_replace_strmem.c:463)
    by 0x408977: substr (parsing.c:61)
    by 0x4089EF: parse_user (parsing.c:73)
    by 0x408D10: cgit_parse_commit (parsing.c:153)
    by 0x40A540: cgit_mk_refinfo (shared.c:171)
    by 0x40A581: cgit_refs_cb (shared.c:181)
    by 0x43DEB3: do_for_each_ref (refs.c:690)
    by 0x41075E: cgit_print_branches (ui-refs.c:191)
    by 0x416EF2: cgit_print_summary (ui-summary.c:56)
    by 0x40780A: summary_fn (cmd.c:120)
    by 0x40667A: process_request (cgit.c:544)
    by 0x404078: cache_process (cache.c:322)
  Address 0x4c7192d is not stack'd, malloc'd or (recently) free'd

 Process terminating with default action of signal 11 (SIGSEGV)
  Access not within mapped region at address 0x502F000
    at 0x4A09400: strncpy (mc_replace_strmem.c:463)
    by 0x408977: substr (parsing.c:61)
    by 0x4089EF: parse_user (parsing.c:73)
    by 0x408D10: cgit_parse_commit (parsing.c:153)
    by 0x40A540: cgit_mk_refinfo (shared.c:171)
    by 0x40A581: cgit_refs_cb (shared.c:181)
    by 0x43DEB3: do_for_each_ref (refs.c:690)
    by 0x41075E: cgit_print_branches (ui-refs.c:191)
    by 0x416EF2: cgit_print_summary (ui-summary.c:56)
    by 0x40780A: summary_fn (cmd.c:120)
    by 0x40667A: process_request (cgit.c:544)
    by 0x404078: cache_process (cache.c:322)

This happens when tail - head == -1 here:
(parsing.c)

  char *substr(const char *head, const char *tail)
  {
          char *buf;

          buf = xmalloc(tail - head + 1);
          strncpy(buf, head, tail - head);
          buf[tail - head] = '\0';
          return buf;
  }

  char *parse_user(char *t, char **name, char **email, unsigned long *date)
  {
          char *p = t;
          int mode = 1;

          while (p && *p) {
                  if (mode == 1 && *p == '<') {
                          *name = substr(t, p - 1);
                          t = p;
                          mode++;
                  } else if (mode == 1 && *p == '\n') {

The fix is to handle the case of (tail < head) before calling xmalloc,
thus avoiding passing an invalid value to xmalloc.

And here's the reproducer:
It was tricky to reproduce, because git prohibits use of an empty "name"
in a commit ID.  To construct the offending commit, I had to resort to
using "git hash-object".

git init -q foo &&
( cd foo &&
  echo a > j && git add . && git ci -q --author='au <T at h.or>' -m. . &&
  h=$(git cat-file commit HEAD|sed 's/au //' \
    |git hash-object -t commit -w --stdin) &&
  git co -q -b test $h &&
  git br -q -D master &&
  git br -q -m test master)
git clone -q --bare foo foo.git

cat <<EOF > in
repo.url=foo.git
repo.path=foo.git
EOF
CGIT_CONFIG=in QUERY_STRING=url=foo.git valgrind ./cgit

The valgrind output is what you see above.

AFAICS, this is not exploitable thanks (ironically) to the use of strncpy.
Since that -1 translates to SIZE_MAX and this is strncpy, not only does it
copy whatever is in "head" (up to first NUL), but it also writes
SIZE_MAX - strlen(head) NUL bytes into the destination buffer, and that
latter is guaranteed to evoke a segfault.  Since cgit is single-threaded,
AFAICS, there is no way that the buffer clobbering can be turned into
an exploit.
ui-repolist: Bold the currently viewed page.

Signed-off-by: Jamie Couture <jamie.couture@gmail.com>
Makefile: add tag target to generate ctags

Signed-off-by: Jamie Couture <jamie.couture@gmail.com>
Revert "filters/syntax-highlighting.sh: work around highlight --force bug"

This reverts commit f50be7fda0a7ab57009169dd5905fcbab8eb5166.

An update with the latest highlight landed in EPEL. This new version
doesn't have the --force bug, so the workaround can now be removed.

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
ui-repolist: do not use agefile if it's date could not be parsed

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
syntax-highlight: when the file has no extension, assume text

There are 2 situations:
1- empty extension: assuming text is better than highlight
   producing no output because of a missing argument.
2- no extension at all: assuming text is better than setting
   the extension to the filename, which is what now happens.

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
README: times, they are a-changin
repo_config: do not let globals override repo settings

This makes it possible to activate the enable_commit_graph,
enable_log_filecount, and enable_log_linecount for individual
repositories, even if the global setting is "0" (default).

The commit that introduced the broken behavior was e189344, and the
commit message of that makes it clear that this wasn't the intended
behavior.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
ui-repolist: Rename section-sort to repository-sort.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
ui: Remember to print ampersand as proper html entities.
scan-tree: Unify gitweb.* and cgit.* settings into one config option.

After some back and forth with Jamie and René, it looks like the git
config semantics are going to be like this:

- gitweb.category maps to the cgit repo config key "section"
- gitweb.description maps to the cgit repo config key "desc"
- gitweb.owner maps to the cgit repo config key "owner"
- cgit.* maps to all cgit repo config keys

This option can be enabled with "enable-git-config=1", and replaces
all previous "enable-gitweb-*" config keys.

The order of operations is as follows:

- git config settings are applied in the order that they exist in
  the git config file
- if the owner is not set from git config, get the owner using the
  usual getpwuid call
- if the description is not set from git config, look inside the
  static $path/description file
- if section-from-path=1, override whatever previous settings were
  inside of git config using the section-from-path logic
- parse $path/cgitrc for local repo.* settings, that override all
  previous settings
ui-repolist: Add "section-sort" flag to control section sorting.

Flag which, when set to "1", will sort the sections on the repository
listing by name. Set this flag to "0" if the order in the cgitrc file
should be preserved. Default value: "1".

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
ui-log: Add "commit-sort" option for controlling commit ordering

This makes it possible to use strict commit date ordering or strict
topological ordering by passing the corresponding flags to "git log".

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
tests: check for proper html entity

Since we're now properly writing ampersand literals as &amp; instead of
as a plain &, we need to update the test accordingly.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Makefile: support FreeBSD libiconv paths

According to Dan Rue <drue@therub.org>, FreeBSD requires the lib paths
to get libiconv from /usr/local.