[PATCH 0/4] Relocate execve() sanity checks
Eric W. Biederman
ebiederm at xmission.com
Tue May 19 15:06:32 UTC 2020
Kees Cook <keescook at chromium.org> writes:
> While looking at the code paths for the proposed O_MAYEXEC flag, I saw
> some things that looked like they should be fixed up.
> exec: Change uselib(2) IS_SREG() failure to EACCES
> This just regularizes the return code on uselib(2).
> exec: Relocate S_ISREG() check
> This moves the S_ISREG() check even earlier than it was already.
> exec: Relocate path_noexec() check
> This adds the path_noexec() check to the same place as the
> S_ISREG() check.
> fs: Include FMODE_EXEC when converting flags to f_mode
> This seemed like an oversight, but I suspect there is some
> reason I couldn't find for why FMODE_EXEC doesn't get set in
> f_mode and just stays in f_flags.
So I took a look at this series.
I think the belt and suspenders approach of adding code in open and then
keeping it in exec and uselib is probably wrong. My sense of the
situation is a belt and suspenders approach is more likely to be
confusing and result in people making mistakes when maintaining the code
than to actually be helpful.
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