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containerd / go-runc

runc bindings for Go
Apache License 2.0
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Remove fchown and uid, gid on pipes #18

Closed justincormack closed 7 years ago

justincormack commented 7 years ago

This makes no sense: open file descriptors do not have ownership, they can be accessed by anyone who has the file descriptor. These anonymous pipes cannot be bound into the filesystem.

On Linux this happens to succeed and do nothing; Posix also allows it to fail.

Signed-off-by: Justin Cormack justin.cormack@docker.com

crosbymichael commented 7 years ago

Are you sure? This is this way for user namespaces to work.

justincormack commented 7 years ago

Hmm, so is that via the ownership of the /proc/self/fd files? Let me check. Otherwise I will make the fchown Linux only.

crosbymichael commented 7 years ago

We just don't do things randomly, there is a reason to the madness ;)

justincormack commented 7 years ago

Well I wasn't trying to remove it randomly either ;) either way I will add a comment...

justincormack commented 7 years ago

Hmm, well fchown does not change the ownership of /proc/self/fd/nn either, so I still don't see how this could help in the userns case... Will try to test actually running a userns.

crosbymichael commented 7 years ago

LGTM