3 Commits

Author	SHA1	Message	Date
Daniel Xu	37cce22dbd	bpf: verifier: Refactor helper access type tracking ... Previously, the verifier was treating all PTR_TO_STACK registers passed to a helper call as potentially written to by the helper. However, all calls to check_stack_range_initialized() already have precise access type information available. Rather than treat ACCESS_HELPER as a proxy for BPF_WRITE, pass enum bpf_access_type to check_stack_range_initialized() to more precisely track helper arguments. One benefit from this precision is that registers tracked as valid spills and passed as a read-only helper argument remain tracked after the call. Rather than being marked STACK_MISC afterwards. An additional benefit is the verifier logs are also more precise. For this particular error, users will enjoy a slightly clearer message. See included selftest updates for examples. Acked-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Link: https://lore.kernel.org/r/ff885c0e5859e0cd12077c3148ff0754cad4f7ed.1736886479.git.dxu@dxuuu.xyz Signed-off-by: Alexei Starovoitov <ast@kernel.org>	2025-01-16 17:51:10 -08:00
Eduard Zingerman	adfdd9c685	selftests/bpf: Introduce __caps_unpriv annotation for tests ... Add a __caps_unpriv annotation so that tests requiring specific capabilities while dropping the rest can conveniently specify them during selftest declaration instead of munging with capabilities at runtime from the testing binary. While at it, let us convert test_verifier_mtu to use this new support instead. Since we do not want to include linux/capability.h, we only defined the four main capabilities BPF subsystem deals with in bpf_misc.h for use in tests. If the user passes a CAP_SYS_NICE or anything else that's not defined in the header, capability parsing code will return a warning. Also reject strtol returning 0. CAP_CHOWN = 0 but we'll never need to use it, and strtol doesn't errno on failed conversion. Fail the test in such a case. The original diff for this idea is available at link [0]. [0]: https://lore.kernel.org/bpf/a1e48f5d9ae133e19adc6adf27e19d585e06bab4.camel@gmail.com Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> [ Kartikeya: rebase on bpf-next, add warn to parse_caps, convert test_verifier_mtu ] Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20241204044757.1483141-4-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>	2024-12-04 09:19:50 -08:00
Daniel Borkmann	82bbe13331	selftests/bpf: Add test for passing in uninit mtu_len ... Add a small test to pass an uninitialized mtu_len to the bpf_check_mtu() helper to probe whether the verifier rejects it under !CAP_PERFMON. # ./vmtest.sh -- ./test_progs -t verifier_mtu [...] ./test_progs -t verifier_mtu [ 1.414712] tsc: Refined TSC clocksource calibration: 3407.993 MHz [ 1.415327] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fcd52370, max_idle_ns: 440795242006 ns [ 1.416463] clocksource: Switched to clocksource tsc [ 1.429842] bpf_testmod: loading out-of-tree module taints kernel. [ 1.430283] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel #510/1 verifier_mtu/uninit/mtu: write rejected:OK #510 verifier_mtu:OK Summary: 1/1 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20241021152809.33343-5-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org>	2024-10-22 15:42:56 -07:00