Re: [PATCH bpf-next v1] selftests/bpf:Enhance bpf ability to detect ksym read error by libcap

On 9/14/24 11:24 AM, Lin Yikai wrote:

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 04716a5e43f1..369c5ad8fc4a 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -183,7 +183,7 @@ NON_CHECK_FEAT_TARGETS := clean docs-clean CHECK_FEAT := $(filter-out $(NON_CHECK_FEAT_TARGETS),$(or $(MAKECMDGOALS), "none")) ifneq ($(CHECK_FEAT),) FEATURE_USER := .selftests -FEATURE_TESTS := llvm +FEATURE_TESTS := llvm libcap FEATURE_DISPLAY := $(FEATURE_TESTS) # Makefile.feature expects OUTPUT to end with a slash @@ -208,6 +208,11 @@ ifeq ($(feature-llvm),1) LLVM_LDFLAGS += $(shell $(LLVM_CONFIG) --ldflags) endif +ifeq ($(feature-libcap), 1)

• CFLAGS += -DHAVE_LIBCAP_SUPPORT
• LDLIBS += -lcap

+endif

[ ... ]

@@ -31,6 +35,55 @@ struct ksyms { static struct ksyms *ksyms; static pthread_mutex_t ksyms_mutex = PTHREAD_MUTEX_INITIALIZER; +#ifdef HAVE_LIBCAP_SUPPORT +#include <sys/capability.h> +static bool bpf_cap__capable(cap_value_t cap) +{

• cap_flag_value_t val;
• cap_t caps = cap_get_proc();
• if (!caps)

• return false;
  

• if (cap_get_flag(caps, cap, CAP_EFFECTIVE, &val) != 0)

Instead of adding new dependency on libcap, please check if capget() can directly be used. Take a look at tools/testing/selftests/bpf/cap_helpers.c.

pw-bot: cr

• val = CAP_CLEAR;
  

• if (cap_free(caps) != 0)

• return false;
  

• return val == CAP_SET;

+}