From 1a1a03bc82e5331aee4cb73d8b194482ac244958 Mon Sep 17 00:00:00 2001 From: Joey Hess Date: Sat, 13 Jun 2020 20:37:22 -0400 Subject: [PATCH] analysis; ACL may be needed --- ..._076d23581986bf53295100f2dd68b5d8._comment | 45 +++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 doc/bugs/git_test_receive_wrapper_fails/comment_1_076d23581986bf53295100f2dd68b5d8._comment diff --git a/doc/bugs/git_test_receive_wrapper_fails/comment_1_076d23581986bf53295100f2dd68b5d8._comment b/doc/bugs/git_test_receive_wrapper_fails/comment_1_076d23581986bf53295100f2dd68b5d8._comment new file mode 100644 index 000000000..8775cbee1 --- /dev/null +++ b/doc/bugs/git_test_receive_wrapper_fails/comment_1_076d23581986bf53295100f2dd68b5d8._comment @@ -0,0 +1,45 @@ +[[!comment format=mdwn + username="joey" + subject="""comment 1""" + date="2020-06-14T00:17:35Z" + content=""" +Stracing git-daemon -f I noticed this: + + [pid 22616] lstat64("/home/b-ikiwiki/source.git/HEAD", {st_mode=S_IFREG|0664, st_size=23, ...}) = 0 + [pid 22616] openat(AT_FDCWD, "/home/b-ikiwiki/source.git/HEAD", O_RDONLY|O_LARGEFILE) = 3 + [pid 22616] read(3, "ref: refs/heads/master\n", 255) = 23 + [pid 22616] read(3, "", 232) = 0 + [pid 22616] close(3) = 0 + [pid 22616] lstat64("/home/b-ikiwiki/source.git/commondir", 0xbf83896c) = -1 ENOENT (No such file or directory) + [pid 22616] access("/home/b-ikiwiki/source.git/./objects/incoming-gXNPXm", X_OK) = -1 EACCES (Permission denied) + [pid 22616] stat64("/home/b-ikiwiki", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 + +So the git diff is in the right cwd, it gets as far as reading HEAD. But then +this permissions error on this incoming directory happens, and it then seems to +give up and search for a different git repo to use in the parent directory (and all the way up to root). + +The directory is created by git earlier in the strace: + + [pid 22559] mkdir("./objects/incoming-gXNPXm", 0700) = 0 + +And here's how it looks: + + drwx------+ 7 ikiwiki-anon ikiwiki-anon 4096 Jun 14 00:22 incoming-y6a8pe/ + +And I think that's the problem, by the time ikiwiki runs it's switched +away from the ikiwiki-anon user that git-daemon uses, and over to the +site user. Which can't read that. + +source.git has an ACL set to let ikiwiki-anon write to it. + + ikisite: eval { shell("setfacl", "-R", "-m", "d:g:$config{gitdaemonuser}:rwX,d:g:$user:rwX,g:$config{gitdaemonuser}:rwX,g:$user:rwX", "$home/source.git") }; + +Can this ACL be adjusted so that all directories created under it will be readable + by the site user (b-ikiwiki)? I don't know ACLs very well. + +Alternatively, `GIT_QUARANTINE_PATH` is set to the directory, so +the C wrapper could fix up its permissions. The wrapper is suid, +so either would need to switch user ID back to ikiwiki-anon, if that's allowed, +or there would need to be an outer wrapper that's not suid (just a shell +script would work) that then runs the regular suid wrapper. +"""]]