I am attempting to write an init replacement that is capability-smart.
Though I'm pleased that prctl() lets me keep capabilities across a
setreuid(), maintaining caps over execve() seems impossible to do right.
I currently see a few options:
- use the CLOEXEC-pipe hack that execcap uses (parent notices
when pipe closes then rushes to set caps on child before
child notices they're gone). This looks like a race to me.
- tweak linux/fs/exec.c (prepare_binprm) to pretend that all
files have cap_inheritable and cap_effective fully set.
This seems a more elegant solution, but requires a kernel
patch.
- exec the child in a stopped state, mess with caps, then
send it SIGCONT. AFAIK, there is no way to do
execve_and_stop.
Is there a better solution available, or one in the works?
I think capabilites may be a key to achieving Pretty Good (tm) security
- but then again, so is running bind as non-root, and nobody even
bothers to do that...
-Eric
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This archive was generated by hypermail 2b29 : Mon Apr 30 2001 - 21:00:11 EST