Re: [PATCH bpf-next v3 01/11] selftests/bpf: Fix caps for __xlated/jited_unpriv
From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Date: 2025-05-01 16:56:52
Also in:
bpf, linux-kselftest, linuxppc-dev, lkml
On Thu, 1 May 2025 at 09:39, Luis Gerhorst [off-list ref] wrote:
Currently, __xlated_unpriv and __jited_unpriv do not work because the
BPF syscall will overwrite info.jited_prog_len and info.xlated_prog_len
with 0 if the process is not bpf_capable(). This bug was not noticed
before, because there is no test that actually uses
__xlated_unpriv/__jited_unpriv.
To resolve this, simply restore the capabilities earlier (but still
after loading the program). Adding this here unconditionally is fine
because the function first checks that the capabilities were initialized
before attempting to restore them.
This will be important later when we add tests that check whether a
speculation barrier was inserted in the correct location.
Signed-off-by: Luis Gerhorst <redacted>
Fixes: 9c9f73391310 ("selftests/bpf: allow checking xlated programs in verifier_* tests")
Fixes: 7d743e4c759c ("selftests/bpf: __jited test tag to check disassembly after jit")
---Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>