On Windows, the os/exec.{Command,CommandContext,LookPath} functions
resolve command names that have neither path separators nor file extension
(e.g., "git") by first looking in the current working directory before
looking in the PATH environment variable.
Go maintainers intended to match cmd.exe's historical behavior.
However, this is pretty much never the intended behavior and as an abundance of precaution
this patch prevents that when executing commands.
Example of commands that docker.exe may execute: `git`, `docker-buildx` (or other cli plugin), `docker-credential-wincred`, `docker`.
Note that this was prompted by the [Go 1.15.7 security fixes](https://blog.golang.org/path-security), but unlike in `go.exe`,
the windows path lookups in docker are not in a code path allowing remote code execution, thus there is no security impact on docker.
Signed-off-by: Tibor Vass <tibor@docker.com>
'CheckInitialized' in the credential-helper library actually invokes
`pass`, which isn't desirable (see #699).
This moves the check to be simpler, and then pass will only be invoked
when it's needed (such as for `docker login` or when pulling from a
private registry).
This logic could also reasonably live in the credential-helper library,
but it's simple enough it seems fine in either location.
Signed-off-by: Euan Kemp <euank@euank.com>
Tibor Vass
Sebastiaan van Stijn
Tonis Tiigi
Euan Kemp
Vincent Demeester
Daniel Nephin
Ivan Markin
Tycho Andersen
Daniel Nephin