[PATCH v4 bpf-next 4/4] selftests/bpf: use CAP_BPF and CAP_TRACING in tests

[Alexei Starovoitov]

Make all test_verifier test exercise CAP_BPF and CAP_TRACING

Signed-off-by: Alexei Starovoitov <a...@kernel.org>
---
 tools/testing/selftests/bpf/test_verifier.c | 46 +++++++++++++++++----
 1 file changed, 38 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/bpf/test_verifier.c 
b/tools/testing/selftests/bpf/test_verifier.c
index d27fd929abb9..0d5567962c4e 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -807,10 +807,20 @@ static void do_test_fixup(struct bpf_test *test, enum 
bpf_prog_type prog_type,
        }
 }
 
+struct libcap {
+       struct __user_cap_header_struct hdr;
+       struct __user_cap_data_struct data[2];
+};
+
 static int set_admin(bool admin)
 {
        cap_t caps;
-       const cap_value_t cap_val = CAP_SYS_ADMIN;
+       /* need CAP_BPF to load progs and CAP_NET_ADMIN to run networking progs,
+        * and CAP_TRACING to create stackmap
+        */
+       const cap_value_t cap_net_admin = CAP_NET_ADMIN;
+       const cap_value_t cap_sys_admin = CAP_SYS_ADMIN;
+       struct libcap *cap;
        int ret = -1;
 
        caps = cap_get_proc();
@@ -818,11 +828,26 @@ static int set_admin(bool admin)
                perror("cap_get_proc");
                return -1;
        }
-       if (cap_set_flag(caps, CAP_EFFECTIVE, 1, &cap_val,
+       cap = (struct libcap *)caps;
+       if (cap_set_flag(caps, CAP_EFFECTIVE, 1, &cap_sys_admin, CAP_CLEAR)) {
+               perror("cap_set_flag clear admin");
+               goto out;
+       }
+       if (cap_set_flag(caps, CAP_EFFECTIVE, 1, &cap_net_admin,
                                admin ? CAP_SET : CAP_CLEAR)) {
-               perror("cap_set_flag");
+               perror("cap_set_flag set_or_clear net");
                goto out;
        }
+       /* libcap is likely old and simply ignores CAP_BPF and CAP_TRACING,
+        * so update effective bits manually
+        */
+       if (admin) {
+               cap->data[1].effective |= 1 << (38 /* CAP_BPF */ - 32);
+               cap->data[1].effective |= 1 << (39 /* CAP_TRACING */ - 32);
+       } else {
+               cap->data[1].effective &= ~(1 << (38 - 32));
+               cap->data[1].effective &= ~(1 << (39 - 32));
+       }
        if (cap_set_proc(caps)) {
                perror("cap_set_proc");
                goto out;
@@ -1051,9 +1076,11 @@ static void do_test_single(struct bpf_test *test, bool 
unpriv,
 
 static bool is_admin(void)
 {
+       cap_flag_value_t net_priv = CAP_CLEAR;
+       bool tracing_priv = false;
+       bool bpf_priv = false;
+       struct libcap *cap;
        cap_t caps;
-       cap_flag_value_t sysadmin = CAP_CLEAR;
-       const cap_value_t cap_val = CAP_SYS_ADMIN;
 
 #ifdef CAP_IS_SUPPORTED
        if (!CAP_IS_SUPPORTED(CAP_SETFCAP)) {
@@ -1066,11 +1093,14 @@ static bool is_admin(void)
                perror("cap_get_proc");
                return false;
        }
-       if (cap_get_flag(caps, cap_val, CAP_EFFECTIVE, &sysadmin))
-               perror("cap_get_flag");
+       cap = (struct libcap *)caps;
+       bpf_priv = cap->data[1].effective & (1 << (38/* CAP_BPF */ - 32));
+       tracing_priv = cap->data[1].effective & (1 << (39/* CAP_TRACING */ - 
32));
+       if (cap_get_flag(caps, CAP_NET_ADMIN, CAP_EFFECTIVE, &net_priv))
+               perror("cap_get_flag NET");
        if (cap_free(caps))
                perror("cap_free");
-       return (sysadmin == CAP_SET);
+       return bpf_priv && tracing_priv && net_priv == CAP_SET;
 }
 
 static void get_unpriv_disabled()
-- 
2.20.0