problem with backslash in directory name

Hi all,

I'm having a problem with submodules that reside in directories that (unwisely) contain a backslash in their name.

Transcript:

### Arrange

$ git init main Initialized empty Git repository in /tmp/test/main/.git/

$ git init sub\\with\\backslash Initialized empty Git repository in /tmp/test/sub\with\backslash/.git/ # This looks okay: the shell interpreted \\ as \, # so we get sub\with\backslash

# Create a log entry in sub\with\backslash
# (it can't be added as a submodule otherwise)
# ((actually I think it's a misfeature, my current use case would be
# easier if git didn't insist on having a log in submodules))
$ touch sub\\with\\backslash/empty.file
$ git -C sub\\with\\backslash add empty.file
$ git -C sub\\with\\backslash commit -m "Added empty.file"
[master (root-commit) a27a485] Added empty.file
  1 file changed, 0 insertions(+), 0 deletions(-)
  create mode 100644 empty.file

### Act/Assert

$ git -C main submodule add ../sub\\with\\backslash fatal: repository '/tmp/test/sub\witackslash' does not exist fatal: clone of '/tmp/test/sub\witackslash' into submodule path 'sub\with\backslash' failed # The first "fatal:" line talks about "witackslash" # Um... "ackslash"? Now that's a nice nickname for a CVE :-)

# Okay, let's see what's actually in that message $ git -C main submodule add ../sub\\with\\backslash 2>&1 | xxd 00000000: 6661 7461 6c3a 2072 6570 6f73 6974 6f72 fatal: repositor 00000010: 7920 272f 746d 702f 7465 7374 2f73 7562 y '/tmp/test/sub 00000020: 5c77 6974 6808 6163 6b73 6c61 7368 2720 \with.ackslash' 00000030: 646f 6573 206e 6f74 2065 7869 7374 0a66 does not exist.f 00000040: 6174 616c 3a20 636c 6f6e 6520 6f66 2027 atal: clone of ' 00000050: 2f74 6d70 2f74 6573 742f 7375 625c 7769 /tmp/test/sub\wi 00000060: 7468 0861 636b 736c 6173 6827 2069 6e74 th.ackslash' int 00000070: 6f20 7375 626d 6f64 756c 6520 7061 7468 o submodule path 00000080: 2027 7375 625c 7769 7468 5c62 6163 6b73 'sub\with\backs 00000090: 6c61 7368 2720 6661 696c 6564 0a lash' failed.

# Yeah, there's a 0x08 at offset 0x25. # It's pretty strange that it is eliding the w following the \b, # not the h preceding it.

So... something inside "git submodule add" is replacing the \b with a backspace control code.

Next I tried something nasty:

$ mv sub\\with\\backslash 'sub: $(bc)' git -C main submodule add '../sub: $(bc)' Cloning into ' $(bc)'... done.

Whatever that "something" is, it is not doing shell expansion, otherwise it would have started an interactive calculator session. Phew :-) I'm still a bit uneasy because I don't know what other escape sequences might get interpreted, and what their effects are.