On 09/27, Brandon Williams wrote: > On 09/27, Junio C Hamano wrote: > > Brandon Williams <bmw...@google.com> writes: > > > > > A normal request to git-daemon is structured as > > > "command path/to/repo\0host=..\0" and due to a bug in an old version of > > > git-daemon 73bb33a94 (daemon: Strictly parse the "extra arg" part of the > > > command, 2009-06-04) we aren't able to place any extra args (separated > > > by NULs) besides the host. > > > > It's a bit unclear if that commit _introduced_ a bug, or just > > noticed an old bug and documented it in its log message. How does > > that commit impact the versons of Git that the updated code is > > capable of interracting with? > > You're right, after reading it again it isn't clear. I'll change this > to indicate that the commit is a fix to a bug and that the fix doesn't > allow us to place any additional args.
Ok how about this wording for the commit msg: daemon: recognize hidden request arguments A normal request to git-daemon is structured as "command path/to/repo\0host=..\0" and due to a bug introduced in 49ba83fb6 (Add virtualization support to git-daemon, 2006-09-19) we aren't able to place any extra arguments (separated by NULs) besides the host otherwise the parsing of those arguments would enter an infinite loop. This bug was fixed in 73bb33a94 (daemon: Strictly parse the "extra arg" part of the command, 2009-06-04) but a check was put in place to disallow extra arguments so that new clients wouldn't trigger this bug in older servers. In order to get around this limitation teach git-daemon to recognize additional request arguments hidden behind a second NUL byte. Requests can then be structured like: "command path/to/repo\0host=..\0\0version=1\0key=value\0". git-daemon can then parse out the extra arguments and set 'GIT_PROTOCOL' accordingly. By placing these extra arguments behind a second NUL byte we can skirt around both the infinite loop bug in 49ba83fb6 (Add virtualization support to git-daemon, 2006-09-19) as well as the explicit disallowing of extra arguments introduced in 73bb33a94 (daemon: Strictly parse the "extra arg" part of the command, 2009-06-04) because both of these versions of git-daemon check for a single NUL byte after the host argument before terminating the argument parsing. This way I'm citing when the bug was actually introduced as well as describing why the 'fix' didn't completely resolve the issue. I also explain a little bit about how this change should work even with very old servers which still have the bug. (I tried to get the introp test to work on a version of git that old but am having some difficulty even getting the old version to launch git-daemon without hanging for some unknown reason) -- Brandon Williams
