selftests/bpf: Update EFAULT {g,s}etsockopt selftests

Instead of assuming EFAULT, let's assume the BPF program's
output is ignored.

Remove "getsockopt: deny arbitrary ctx->retval" because it
was actually testing optlen. We have separate set of tests
for retval.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230511170456.1759459-3-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

diff --git a/tools/testing/selftests/bpf/prog_tests/sockopt.c b/tools/testing/selftests/bpf/prog_tests/sockopt.c
index aa4debf..33dd453 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/sockopt.c
+++ b/tools/testing/selftests/bpf/prog_tests/sockopt.c
@@ -5,10 +5,15 @@
 static char bpf_log_buf[4096];
 static bool verbose;
 
+#ifndef PAGE_SIZE
+#define PAGE_SIZE 4096
+#endif
+
 enum sockopt_test_error {
        OK = 0,
        DENY_LOAD,
        DENY_ATTACH,
+       EOPNOTSUPP_GETSOCKOPT,
        EPERM_GETSOCKOPT,
        EFAULT_GETSOCKOPT,
        EPERM_SETSOCKOPT,
@@ -273,10 +278,31 @@ static struct sockopt_test {
                .error = EFAULT_GETSOCKOPT,
        },
        {
-               .descr = "getsockopt: deny arbitrary ctx->retval",
+               .descr = "getsockopt: ignore >PAGE_SIZE optlen",
                .insns = {
-                       /* ctx->retval = 123 */
-                       BPF_MOV64_IMM(BPF_REG_0, 123),
+                       /* write 0xFF to the first optval byte */
+
+                       /* r6 = ctx->optval */
+                       BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1,
+                                   offsetof(struct bpf_sockopt, optval)),
+                       /* r2 = ctx->optval */
+                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_6),
+                       /* r6 = ctx->optval + 1 */
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 1),
+
+                       /* r7 = ctx->optval_end */
+                       BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_1,
+                                   offsetof(struct bpf_sockopt, optval_end)),
+
+                       /* if (ctx->optval + 1 <= ctx->optval_end) { */
+                       BPF_JMP_REG(BPF_JGT, BPF_REG_6, BPF_REG_7, 1),
+                       /* ctx->optval[0] = 0xF0 */
+                       BPF_ST_MEM(BPF_B, BPF_REG_2, 0, 0xFF),
+                       /* } */
+
+                       /* retval changes are ignored */
+                       /* ctx->retval = 5 */
+                       BPF_MOV64_IMM(BPF_REG_0, 5),
                        BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_0,
                                    offsetof(struct bpf_sockopt, retval)),
 
@@ -287,9 +313,11 @@ static struct sockopt_test {
                .attach_type = BPF_CGROUP_GETSOCKOPT,
                .expected_attach_type = BPF_CGROUP_GETSOCKOPT,
 
-               .get_optlen = 64,
-
-               .error = EFAULT_GETSOCKOPT,
+               .get_level = 1234,
+               .get_optname = 5678,
+               .get_optval = {}, /* the changes are ignored */
+               .get_optlen = PAGE_SIZE + 1,
+               .error = EOPNOTSUPP_GETSOCKOPT,
        },
        {
                .descr = "getsockopt: support smaller ctx->optlen",
@@ -649,6 +677,45 @@ static struct sockopt_test {
                .error = EFAULT_SETSOCKOPT,
        },
        {
+               .descr = "setsockopt: ignore >PAGE_SIZE optlen",
+               .insns = {
+                       /* write 0xFF to the first optval byte */
+
+                       /* r6 = ctx->optval */
+                       BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1,
+                                   offsetof(struct bpf_sockopt, optval)),
+                       /* r2 = ctx->optval */
+                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_6),
+                       /* r6 = ctx->optval + 1 */
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 1),
+
+                       /* r7 = ctx->optval_end */
+                       BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_1,
+                                   offsetof(struct bpf_sockopt, optval_end)),
+
+                       /* if (ctx->optval + 1 <= ctx->optval_end) { */
+                       BPF_JMP_REG(BPF_JGT, BPF_REG_6, BPF_REG_7, 1),
+                       /* ctx->optval[0] = 0xF0 */
+                       BPF_ST_MEM(BPF_B, BPF_REG_2, 0, 0xF0),
+                       /* } */
+
+                       BPF_MOV64_IMM(BPF_REG_0, 1),
+                       BPF_EXIT_INSN(),
+               },
+               .attach_type = BPF_CGROUP_SETSOCKOPT,
+               .expected_attach_type = BPF_CGROUP_SETSOCKOPT,
+
+               .set_level = SOL_IP,
+               .set_optname = IP_TOS,
+               .set_optval = {},
+               .set_optlen = PAGE_SIZE + 1,
+
+               .get_level = SOL_IP,
+               .get_optname = IP_TOS,
+               .get_optval = {}, /* the changes are ignored */
+               .get_optlen = 4,
+       },
+       {
                .descr = "setsockopt: allow changing ctx->optlen within bounds",
                .insns = {
                        /* r6 = ctx->optval */
@@ -906,6 +973,13 @@ static int run_test(int cgroup_fd, struct sockopt_test *test)
        }
 
        if (test->set_optlen) {
+               if (test->set_optlen >= PAGE_SIZE) {
+                       int num_pages = test->set_optlen / PAGE_SIZE;
+                       int remainder = test->set_optlen % PAGE_SIZE;
+
+                       test->set_optlen = num_pages * sysconf(_SC_PAGESIZE) + remainder;
+               }
+
                err = setsockopt(sock_fd, test->set_level, test->set_optname,
                                 test->set_optval, test->set_optlen);
                if (err) {
@@ -921,7 +995,15 @@ static int run_test(int cgroup_fd, struct sockopt_test *test)
        }
 
        if (test->get_optlen) {
+               if (test->get_optlen >= PAGE_SIZE) {
+                       int num_pages = test->get_optlen / PAGE_SIZE;
+                       int remainder = test->get_optlen % PAGE_SIZE;
+
+                       test->get_optlen = num_pages * sysconf(_SC_PAGESIZE) + remainder;
+               }
+
                optval = malloc(test->get_optlen);
+               memset(optval, 0, test->get_optlen);
                socklen_t optlen = test->get_optlen;
                socklen_t expected_get_optlen = test->get_optlen_ret ?:
                        test->get_optlen;
@@ -929,6 +1011,8 @@ static int run_test(int cgroup_fd, struct sockopt_test *test)
                err = getsockopt(sock_fd, test->get_level, test->get_optname,
                                 optval, &optlen);
                if (err) {
+                       if (errno == EOPNOTSUPP && test->error == EOPNOTSUPP_GETSOCKOPT)
+                               goto free_optval;
                        if (errno == EPERM && test->error == EPERM_GETSOCKOPT)
                                goto free_optval;
                        if (errno == EFAULT && test->error == EFAULT_GETSOCKOPT)