test_dev_cgroup currently loads a small bpf program allowing any access on urandom and zero devices, disabling access to any other device. It makes migrating this test to test_progs impossible, since this one manipulates extensively /dev/null.
Allow /dev/null manipulation in dev_cgroup program to make its usage in test_progs framework possible. Update test_dev_cgroup.c as well to match this change while it has not been removed.
Signed-off-by: Alexis Lothoré (eBPF Foundation) alexis.lothore@bootlin.com --- tools/testing/selftests/bpf/progs/dev_cgroup.c | 4 ++-- tools/testing/selftests/bpf/test_dev_cgroup.c | 18 +++++++++--------- 2 files changed, 11 insertions(+), 11 deletions(-)
diff --git a/tools/testing/selftests/bpf/progs/dev_cgroup.c b/tools/testing/selftests/bpf/progs/dev_cgroup.c index 79b54a4fa244..c1dfbd2b56fc 100644 --- a/tools/testing/selftests/bpf/progs/dev_cgroup.c +++ b/tools/testing/selftests/bpf/progs/dev_cgroup.c @@ -41,14 +41,14 @@ int bpf_prog1(struct bpf_cgroup_dev_ctx *ctx) bpf_trace_printk(fmt, sizeof(fmt), ctx->major, ctx->minor); #endif
- /* Allow access to /dev/zero and /dev/random. + /* Allow access to /dev/null and /dev/urandom. * Forbid everything else. */ if (ctx->major != 1 || type != BPF_DEVCG_DEV_CHAR) return 0;
switch (ctx->minor) { - case 5: /* 1:5 /dev/zero */ + case 3: /* 1:3 /dev/null */ case 9: /* 1:9 /dev/urandom */ return 1; } diff --git a/tools/testing/selftests/bpf/test_dev_cgroup.c b/tools/testing/selftests/bpf/test_dev_cgroup.c index adeaf63cb6fa..33f544f0005a 100644 --- a/tools/testing/selftests/bpf/test_dev_cgroup.c +++ b/tools/testing/selftests/bpf/test_dev_cgroup.c @@ -54,25 +54,25 @@ int main(int argc, char **argv) goto err; }
- /* All operations with /dev/zero and and /dev/urandom are allowed, + /* All operations with /dev/null and /dev/urandom are allowed, * everything else is forbidden. */ - assert(system("rm -f /tmp/test_dev_cgroup_null") == 0); - assert(system("mknod /tmp/test_dev_cgroup_null c 1 3")); - assert(system("rm -f /tmp/test_dev_cgroup_null") == 0); - - /* /dev/zero is whitelisted */ assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0); - assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0); + assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5")); assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
- assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0); + /* /dev/null is whitelisted */ + assert(system("rm -f /tmp/test_dev_cgroup_null") == 0); + assert(system("mknod /tmp/test_dev_cgroup_null c 1 3") == 0); + assert(system("rm -f /tmp/test_dev_cgroup_null") == 0); + + assert(system("dd if=/dev/urandom of=/dev/null count=64") == 0);
/* src is allowed, target is forbidden */ assert(system("dd if=/dev/urandom of=/dev/full count=64"));
/* src is forbidden, target is allowed */ - assert(system("dd if=/dev/random of=/dev/zero count=64")); + assert(system("dd if=/dev/random of=/dev/null count=64"));
error = 0; printf("test_dev_cgroup:PASS\n");