A set of test cases to check behavior of callback handling logic,
check if verifier catches the following situations:
- program not safe on second callback iteration;
- program not safe on zero callback iterations;
- infinite loop inside a callback.
Verify that callback logic works for bpf_loop, bpf_for_each_map_elem,
bpf_user_ringbuf_drain, bpf_find_vma.
Signed-off-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
---
.../selftests/bpf/prog_tests/verifier.c | 2 +
.../bpf/progs/verifier_iterating_callbacks.c | 147 ++++++++++++++++++
2 files changed, 149 insertions(+)
create mode 100644 tools/testing/selftests/bpf/progs/verifier_iterating_callbacks.c
diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c
index e5c61aa6604a..5cfa7a6316b6 100644
--- a/tools/testing/selftests/bpf/prog_tests/verifier.c
+++ b/tools/testing/selftests/bpf/prog_tests/verifier.c
@@ -31,6 +31,7 @@
#include "verifier_helper_restricted.skel.h"
#include "verifier_helper_value_access.skel.h"
#include "verifier_int_ptr.skel.h"
+#include "verifier_iterating_callbacks.skel.h"
#include "verifier_jeq_infer_not_null.skel.h"
#include "verifier_ld_ind.skel.h"
#include "verifier_ldsx.skel.h"
@@ -139,6 +140,7 @@ void test_verifier_helper_packet_access(void) { RUN(verifier_helper_packet_acces
void test_verifier_helper_restricted(void) { RUN(verifier_helper_restricted); }
void test_verifier_helper_value_access(void) { RUN(verifier_helper_value_access); }
void test_verifier_int_ptr(void) { RUN(verifier_int_ptr); }
+void test_verifier_iterating_callbacks(void) { RUN(verifier_iterating_callbacks); }
void test_verifier_jeq_infer_not_null(void) { RUN(verifier_jeq_infer_not_null); }
void test_verifier_ld_ind(void) { RUN(verifier_ld_ind); }
void test_verifier_ldsx(void) { RUN(verifier_ldsx); }
diff --git a/tools/testing/selftests/bpf/progs/verifier_iterating_callbacks.c b/tools/testing/selftests/bpf/progs/verifier_iterating_callbacks.c
new file mode 100644
index 000000000000..fa9429f77a81
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/verifier_iterating_callbacks.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __uint(max_entries, 8);
+ __type(key, __u32);
+ __type(value, __u64);
+} map SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_USER_RINGBUF);
+ __uint(max_entries, 8);
+} ringbuf SEC(".maps");
+
+struct vm_area_struct;
+struct bpf_map;
+
+struct buf_context {
+ char *buf;
+};
+
+struct num_context {
+ __u64 i;
+};
+
+__u8 choice_arr[2] = { 0, 1 };
+
+static int unsafe_on_2nd_iter_cb(__u32 idx, struct buf_context *ctx)
+{
+ if (idx == 0) {
+ ctx->buf = (char *)(0xDEAD);
+ return 0;
+ }
+
+ if (bpf_probe_read_user(ctx->buf, 8, (void *)(0xBADC0FFEE)))
+ return 1;
+
+ return 0;
+}
+
+SEC("?raw_tp")
+__failure __msg("R1 type=scalar expected=fp")
+int unsafe_on_2nd_iter(void *unused)
+{
+ char buf[4];
+ struct buf_context loop_ctx = { .buf = buf };
+
+ bpf_loop(100, unsafe_on_2nd_iter_cb, &loop_ctx, 0);
+ return 0;
+}
+
+static int unsafe_on_zero_iter_cb(__u32 idx, struct num_context *ctx)
+{
+ ctx->i = 0;
+ return 0;
+}
+
+SEC("?raw_tp")
+__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
+int unsafe_on_zero_iter(void *unused)
+{
+ struct num_context loop_ctx = { .i = 32 };
+
+ bpf_loop(100, unsafe_on_zero_iter_cb, &loop_ctx, 0);
+ return choice_arr[loop_ctx.i];
+}
+
+static int loop_detection_cb(__u32 idx, struct num_context *ctx)
+{
+ for (;;) {}
+ return 0;
+}
+
+SEC("?raw_tp")
+__failure __msg("infinite loop detected")
+int loop_detection(void *unused)
+{
+ struct num_context loop_ctx = { .i = 0 };
+
+ bpf_loop(100, loop_detection_cb, &loop_ctx, 0);
+ return 0;
+}
+
+static __always_inline __u64 oob_state_machine(struct num_context *ctx)
+{
+ switch (ctx->i) {
+ case 0:
+ ctx->i = 1;
+ break;
+ case 1:
+ ctx->i = 32;
+ break;
+ }
+ return 0;
+}
+
+static __u64 for_each_map_elem_cb(struct bpf_map *map, __u32 *key, __u64 *val, void *data)
+{
+ return oob_state_machine(data);
+}
+
+SEC("?raw_tp")
+__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
+int unsafe_for_each_map_elem(void *unused)
+{
+ struct num_context loop_ctx = { .i = 0 };
+
+ bpf_for_each_map_elem(&map, for_each_map_elem_cb, &loop_ctx, 0);
+ return choice_arr[loop_ctx.i];
+}
+
+static __u64 ringbuf_drain_cb(struct bpf_dynptr *dynptr, void *data)
+{
+ return oob_state_machine(data);
+}
+
+SEC("?raw_tp")
+__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
+int unsafe_ringbuf_drain(void *unused)
+{
+ struct num_context loop_ctx = { .i = 0 };
+
+ bpf_user_ringbuf_drain(&ringbuf, ringbuf_drain_cb, &loop_ctx, 0);
+ return choice_arr[loop_ctx.i];
+}
+
+static __u64 find_vma_cb(struct task_struct *task, struct vm_area_struct *vma, void *data)
+{
+ return oob_state_machine(data);
+}
+
+SEC("?raw_tp")
+__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
+int unsafe_find_vma(void *unused)
+{
+ struct task_struct *task = bpf_get_current_task_btf();
+ struct num_context loop_ctx = { .i = 0 };
+
+ bpf_find_vma(task, 0, find_vma_cb, &loop_ctx, 0);
+ return choice_arr[loop_ctx.i];
+}
+
+char _license[] SEC("license") = "GPL";
--
2.42.0
