410 lines
7.8 KiB
C
410 lines
7.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "bpf_misc.h"
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#include "bpf_experimental.h"
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, 8);
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__type(key, __u32);
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__type(value, __u64);
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} map SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_USER_RINGBUF);
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__uint(max_entries, 8);
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} ringbuf SEC(".maps");
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struct vm_area_struct;
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struct bpf_map;
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struct buf_context {
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char *buf;
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};
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struct num_context {
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__u64 i;
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__u64 j;
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};
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__u8 choice_arr[2] = { 0, 1 };
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static int unsafe_on_2nd_iter_cb(__u32 idx, struct buf_context *ctx)
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{
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if (idx == 0) {
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ctx->buf = (char *)(0xDEAD);
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return 0;
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}
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if (bpf_probe_read_user(ctx->buf, 8, (void *)(0xBADC0FFEE)))
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return 1;
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return 0;
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}
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SEC("?raw_tp")
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__failure __msg("R1 type=scalar expected=fp")
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int unsafe_on_2nd_iter(void *unused)
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{
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char buf[4];
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struct buf_context loop_ctx = { .buf = buf };
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bpf_loop(100, unsafe_on_2nd_iter_cb, &loop_ctx, 0);
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return 0;
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}
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static int unsafe_on_zero_iter_cb(__u32 idx, struct num_context *ctx)
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{
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ctx->i = 0;
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return 0;
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}
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SEC("?raw_tp")
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__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
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int unsafe_on_zero_iter(void *unused)
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{
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struct num_context loop_ctx = { .i = 32 };
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bpf_loop(100, unsafe_on_zero_iter_cb, &loop_ctx, 0);
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return choice_arr[loop_ctx.i];
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}
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static int widening_cb(__u32 idx, struct num_context *ctx)
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{
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++ctx->i;
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return 0;
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}
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SEC("?raw_tp")
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__success
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int widening(void *unused)
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{
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struct num_context loop_ctx = { .i = 0, .j = 1 };
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bpf_loop(100, widening_cb, &loop_ctx, 0);
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/* loop_ctx.j is not changed during callback iteration,
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* verifier should not apply widening to it.
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*/
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return choice_arr[loop_ctx.j];
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}
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static int loop_detection_cb(__u32 idx, struct num_context *ctx)
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{
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for (;;) {}
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return 0;
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}
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SEC("?raw_tp")
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__failure __msg("infinite loop detected")
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int loop_detection(void *unused)
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{
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struct num_context loop_ctx = { .i = 0 };
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bpf_loop(100, loop_detection_cb, &loop_ctx, 0);
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return 0;
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}
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static __always_inline __u64 oob_state_machine(struct num_context *ctx)
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{
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switch (ctx->i) {
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case 0:
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ctx->i = 1;
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break;
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case 1:
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ctx->i = 32;
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break;
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}
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return 0;
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}
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static __u64 for_each_map_elem_cb(struct bpf_map *map, __u32 *key, __u64 *val, void *data)
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{
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return oob_state_machine(data);
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}
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SEC("?raw_tp")
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__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
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int unsafe_for_each_map_elem(void *unused)
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{
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struct num_context loop_ctx = { .i = 0 };
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bpf_for_each_map_elem(&map, for_each_map_elem_cb, &loop_ctx, 0);
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return choice_arr[loop_ctx.i];
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}
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static __u64 ringbuf_drain_cb(struct bpf_dynptr *dynptr, void *data)
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{
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return oob_state_machine(data);
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}
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SEC("?raw_tp")
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__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
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int unsafe_ringbuf_drain(void *unused)
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{
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struct num_context loop_ctx = { .i = 0 };
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bpf_user_ringbuf_drain(&ringbuf, ringbuf_drain_cb, &loop_ctx, 0);
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return choice_arr[loop_ctx.i];
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}
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static __u64 find_vma_cb(struct task_struct *task, struct vm_area_struct *vma, void *data)
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{
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return oob_state_machine(data);
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}
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SEC("?raw_tp")
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__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
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int unsafe_find_vma(void *unused)
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{
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struct task_struct *task = bpf_get_current_task_btf();
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struct num_context loop_ctx = { .i = 0 };
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bpf_find_vma(task, 0, find_vma_cb, &loop_ctx, 0);
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return choice_arr[loop_ctx.i];
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}
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static int iter_limit_cb(__u32 idx, struct num_context *ctx)
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{
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ctx->i++;
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return 0;
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}
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SEC("?raw_tp")
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__success
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int bpf_loop_iter_limit_ok(void *unused)
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{
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struct num_context ctx = { .i = 0 };
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bpf_loop(1, iter_limit_cb, &ctx, 0);
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return choice_arr[ctx.i];
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}
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SEC("?raw_tp")
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__failure __msg("invalid access to map value, value_size=2 off=2 size=1")
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int bpf_loop_iter_limit_overflow(void *unused)
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{
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struct num_context ctx = { .i = 0 };
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bpf_loop(2, iter_limit_cb, &ctx, 0);
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return choice_arr[ctx.i];
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}
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static int iter_limit_level2a_cb(__u32 idx, struct num_context *ctx)
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{
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ctx->i += 100;
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return 0;
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}
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static int iter_limit_level2b_cb(__u32 idx, struct num_context *ctx)
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{
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ctx->i += 10;
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return 0;
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}
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static int iter_limit_level1_cb(__u32 idx, struct num_context *ctx)
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{
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ctx->i += 1;
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bpf_loop(1, iter_limit_level2a_cb, ctx, 0);
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bpf_loop(1, iter_limit_level2b_cb, ctx, 0);
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return 0;
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}
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/* Check that path visiting every callback function once had been
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* reached by verifier. Variables 'ctx{1,2}i' below serve as flags,
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* with each decimal digit corresponding to a callback visit marker.
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*/
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SEC("socket")
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__success __retval(111111)
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int bpf_loop_iter_limit_nested(void *unused)
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{
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struct num_context ctx1 = { .i = 0 };
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struct num_context ctx2 = { .i = 0 };
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__u64 a, b, c;
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bpf_loop(1, iter_limit_level1_cb, &ctx1, 0);
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bpf_loop(1, iter_limit_level1_cb, &ctx2, 0);
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a = ctx1.i;
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b = ctx2.i;
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/* Force 'ctx1.i' and 'ctx2.i' precise. */
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c = choice_arr[(a + b) % 2];
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/* This makes 'c' zero, but neither clang nor verifier know it. */
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c /= 10;
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/* Make sure that verifier does not visit 'impossible' states:
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* enumerate all possible callback visit masks.
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*/
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if (a != 0 && a != 1 && a != 11 && a != 101 && a != 111 &&
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b != 0 && b != 1 && b != 11 && b != 101 && b != 111)
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asm volatile ("r0 /= 0;" ::: "r0");
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return 1000 * a + b + c;
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}
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struct iter_limit_bug_ctx {
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__u64 a;
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__u64 b;
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__u64 c;
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};
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static __naked void iter_limit_bug_cb(void)
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{
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/* This is the same as C code below, but written
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* in assembly to control which branches are fall-through.
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*
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* switch (bpf_get_prandom_u32()) {
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* case 1: ctx->a = 42; break;
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* case 2: ctx->b = 42; break;
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* default: ctx->c = 42; break;
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* }
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*/
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asm volatile (
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"r9 = r2;"
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"call %[bpf_get_prandom_u32];"
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"r1 = r0;"
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"r2 = 42;"
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"r0 = 0;"
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"if r1 == 0x1 goto 1f;"
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"if r1 == 0x2 goto 2f;"
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"*(u64 *)(r9 + 16) = r2;"
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"exit;"
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"1: *(u64 *)(r9 + 0) = r2;"
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"exit;"
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"2: *(u64 *)(r9 + 8) = r2;"
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"exit;"
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:
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: __imm(bpf_get_prandom_u32)
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: __clobber_all
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);
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}
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SEC("tc")
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__failure
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__flag(BPF_F_TEST_STATE_FREQ)
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int iter_limit_bug(struct __sk_buff *skb)
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{
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struct iter_limit_bug_ctx ctx = { 7, 7, 7 };
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bpf_loop(2, iter_limit_bug_cb, &ctx, 0);
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/* This is the same as C code below,
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* written in assembly to guarantee checks order.
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*
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* if (ctx.a == 42 && ctx.b == 42 && ctx.c == 7)
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* asm volatile("r1 /= 0;":::"r1");
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*/
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asm volatile (
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"r1 = *(u64 *)%[ctx_a];"
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"if r1 != 42 goto 1f;"
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"r1 = *(u64 *)%[ctx_b];"
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"if r1 != 42 goto 1f;"
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"r1 = *(u64 *)%[ctx_c];"
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"if r1 != 7 goto 1f;"
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"r1 /= 0;"
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"1:"
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:
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: [ctx_a]"m"(ctx.a),
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[ctx_b]"m"(ctx.b),
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[ctx_c]"m"(ctx.c)
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: "r1"
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);
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return 0;
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}
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#define ARR_SZ 1000000
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int zero;
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char arr[ARR_SZ];
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SEC("socket")
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__success __retval(0xd495cdc0)
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int cond_break1(const void *ctx)
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{
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unsigned long i;
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unsigned int sum = 0;
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for (i = zero; i < ARR_SZ; cond_break, i++)
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sum += i;
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for (i = zero; i < ARR_SZ; i++) {
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barrier_var(i);
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sum += i + arr[i];
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cond_break;
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}
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return sum;
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}
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SEC("socket")
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__success __retval(999000000)
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int cond_break2(const void *ctx)
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{
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int i, j;
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int sum = 0;
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for (i = zero; i < 1000; cond_break, i++)
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for (j = zero; j < 1000; j++) {
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sum += i + j;
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cond_break;
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}
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return sum;
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}
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static __noinline int loop(void)
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{
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int i, sum = 0;
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for (i = zero; i <= 1000000; i++, cond_break)
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sum += i;
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return sum;
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}
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SEC("socket")
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__success __retval(0x6a5a2920)
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int cond_break3(const void *ctx)
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{
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return loop();
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}
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SEC("socket")
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__success __retval(1)
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int cond_break4(const void *ctx)
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{
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int cnt = zero;
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for (;;) {
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/* should eventually break out of the loop */
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cond_break;
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cnt++;
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}
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/* if we looped a bit, it's a success */
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return cnt > 1 ? 1 : 0;
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}
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static __noinline int static_subprog(void)
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{
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int cnt = zero;
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for (;;) {
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cond_break;
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cnt++;
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}
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return cnt;
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}
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SEC("socket")
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__success __retval(1)
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int cond_break5(const void *ctx)
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{
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int cnt1 = zero, cnt2;
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for (;;) {
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cond_break;
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cnt1++;
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}
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cnt2 = static_subprog();
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/* main and subprog have to loop a bit */
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return cnt1 > 1 && cnt2 > 1 ? 1 : 0;
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}
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char _license[] SEC("license") = "GPL";
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