Faking the UID and GID

Some programs expect that, when they create a file or directory, stat() will show that the object is owned by the same user ID that is returned by getuid(). For this reason, PlashGlibc patches getuid() and similar calls so that they can return the UID or GID of the user that created the sandbox instead of returning the UID/GID created for the sandbox by ChrootSetuidJail.

This feature is enabled by setting the following environment variables:

PLASH_FAKE_UID
PLASH_FAKE_GID
PLASH_FAKE_EUID
PLASH_FAKE_EGID

UID/GID faking is enabled by pola-run by default:

$ id -u
1000
$ pola-run -B -e env | grep FAKE
PLASH_FAKE_UID=1000
PLASH_FAKE_GID=1000
PLASH_FAKE_EGID=1000
PLASH_FAKE_EUID=1000