Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2023-04-24

We've added 5 non-merge commits during the last 3 day(s) which contain
a total of 7 files changed, 87 insertions(+), 44 deletions(-).

The main changes are:

1) Workaround for bpf iter selftest due to lack of subprog support
   in precision tracking, from Andrii.

2) Disable bpf_refcount_acquire kfunc until races are fixed, from Dave.

3) One more test_verifier test converted from asm macro to asm in C,
   from Eduard.

4) Fix build with NETFILTER=y INET=n config, from Florian.

5) Add __rcu_read_{lock,unlock} into deny list, from Yafang.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next:
  selftests/bpf: avoid mark_all_scalars_precise() trigger in one of iter tests
  bpf: Add __rcu_read_{lock,unlock} into btf id deny list
  bpf: Disable bpf_refcount_acquire kfunc calls until race conditions are fixed
  selftests/bpf: verifier/prevent_map_lookup converted to inline assembly
  bpf: fix link failure with NETFILTER=y INET=n
====================

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: kuba-moo

include/linux/bpf_types.h

@@ -79,7 +79,7 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_LSM, lsm,
 #endif
 BPF_PROG_TYPE(BPF_PROG_TYPE_SYSCALL, bpf_syscall,
 	      void *, void *)
-#ifdef CONFIG_NETFILTER
+#ifdef CONFIG_NETFILTER_BPF_LINK
 BPF_PROG_TYPE(BPF_PROG_TYPE_NETFILTER, netfilter,
 	      struct bpf_nf_ctx, struct bpf_nf_ctx)
 #endif

kernel/bpf/verifier.c

@@ -10509,7 +10509,10 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_
 				verbose(env, "arg#%d doesn't point to a type with bpf_refcount field\n", i);
 				return -EINVAL;
 			}
-
+			if (rec->refcount_off >= 0) {
+				verbose(env, "bpf_refcount_acquire calls are disabled for now\n");
+				return -EINVAL;
+			}
 			meta->arg_refcount_acquire.btf = reg->btf;
 			meta->arg_refcount_acquire.btf_id = reg->btf_id;
 			break;
@@ -18668,6 +18671,10 @@ BTF_ID(func, rcu_read_unlock_strict)
 BTF_ID(func, preempt_count_add)
 BTF_ID(func, preempt_count_sub)
 #endif
+#ifdef CONFIG_PREEMPT_RCU
+BTF_ID(func, __rcu_read_lock)
+BTF_ID(func, __rcu_read_unlock)
+#endif
 BTF_SET_END(btf_id_deny)
 
 static bool can_be_sleepable(struct bpf_prog *prog)

tools/testing/selftests/bpf/prog_tests/refcounted_kptr.c

@@ -9,10 +9,8 @@
 
 void test_refcounted_kptr(void)
 {
-	RUN_TESTS(refcounted_kptr);
 }
 
 void test_refcounted_kptr_fail(void)
 {
-	RUN_TESTS(refcounted_kptr_fail);
 }

tools/testing/selftests/bpf/prog_tests/verifier.c

@@ -42,6 +42,7 @@
 #include "verifier_meta_access.skel.h"
 #include "verifier_netfilter_ctx.skel.h"
 #include "verifier_netfilter_retcode.skel.h"
+#include "verifier_prevent_map_lookup.skel.h"
 #include "verifier_raw_stack.skel.h"
 #include "verifier_raw_tp_writable.skel.h"
 #include "verifier_reg_equal.skel.h"
@@ -140,6 +141,7 @@ void test_verifier_masking(void)              { RUN(verifier_masking); }
 void test_verifier_meta_access(void)          { RUN(verifier_meta_access); }
 void test_verifier_netfilter_ctx(void)        { RUN(verifier_netfilter_ctx); }
 void test_verifier_netfilter_retcode(void)    { RUN(verifier_netfilter_retcode); }
+void test_verifier_prevent_map_lookup(void)   { RUN(verifier_prevent_map_lookup); }
 void test_verifier_raw_stack(void)            { RUN(verifier_raw_stack); }
 void test_verifier_raw_tp_writable(void)      { RUN(verifier_raw_tp_writable); }
 void test_verifier_reg_equal(void)            { RUN(verifier_reg_equal); }

tools/testing/selftests/bpf/progs/iters.c

@@ -651,25 +651,29 @@ int iter_stack_array_loop(const void *ctx)
 	return sum;
 }
 
-static __noinline void fill(struct bpf_iter_num *it, int *arr, __u32 n, int mul)
+#define ARR_SZ 16
+
+static __noinline void fill(struct bpf_iter_num *it, int *arr, int mul)
 {
-	int *t, i;
+	int *t;
+	__u64 i;
 
 	while ((t = bpf_iter_num_next(it))) {
 		i = *t;
-		if (i >= n)
+		if (i >= ARR_SZ)
 			break;
 		arr[i] =  i * mul;
 	}
 }
 
-static __noinline int sum(struct bpf_iter_num *it, int *arr, __u32 n)
+static __noinline int sum(struct bpf_iter_num *it, int *arr)
 {
-	int *t, i, sum = 0;;
+	int *t, sum = 0;;
+	__u64 i;
 
 	while ((t = bpf_iter_num_next(it))) {
 		i = *t;
-		if (i >= n)
+		if (i >= ARR_SZ)
 			break;
 		sum += arr[i];
 	}
@@ -681,7 +685,7 @@ SEC("raw_tp")
 __success
 int iter_pass_iter_ptr_to_subprog(const void *ctx)
 {
-	int arr1[16], arr2[32];
+	int arr1[ARR_SZ], arr2[ARR_SZ];
 	struct bpf_iter_num it;
 	int n, sum1, sum2;
 
@@ -690,25 +694,25 @@ int iter_pass_iter_ptr_to_subprog(const void *ctx)
 	/* fill arr1 */
 	n = ARRAY_SIZE(arr1);
 	bpf_iter_num_new(&it, 0, n);
-	fill(&it, arr1, n, 2);
+	fill(&it, arr1, 2);
 	bpf_iter_num_destroy(&it);
 
 	/* fill arr2 */
 	n = ARRAY_SIZE(arr2);
 	bpf_iter_num_new(&it, 0, n);
-	fill(&it, arr2, n, 10);
+	fill(&it, arr2, 10);
 	bpf_iter_num_destroy(&it);
 
 	/* sum arr1 */
 	n = ARRAY_SIZE(arr1);
 	bpf_iter_num_new(&it, 0, n);
-	sum1 = sum(&it, arr1, n);
+	sum1 = sum(&it, arr1);
 	bpf_iter_num_destroy(&it);
 
 	/* sum arr2 */
 	n = ARRAY_SIZE(arr2);
 	bpf_iter_num_new(&it, 0, n);
-	sum2 = sum(&it, arr2, n);
+	sum2 = sum(&it, arr2);
 	bpf_iter_num_destroy(&it);
 
 	bpf_printk("sum1=%d, sum2=%d", sum1, sum2);

tools/testing/selftests/bpf/progs/verifier_prevent_map_lookup.c

@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Converted from tools/testing/selftests/bpf/verifier/prevent_map_lookup.c */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+struct {
+	__uint(type, BPF_MAP_TYPE_STACK_TRACE);
+	__uint(max_entries, 1);
+	__type(key, __u32);
+	__type(value, __u64);
+} map_stacktrace SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
+	__uint(max_entries, 8);
+	__uint(key_size, sizeof(int));
+	__array(values, void (void));
+} map_prog2_socket SEC(".maps");
+
+SEC("perf_event")
+__description("prevent map lookup in stack trace")
+__failure __msg("cannot pass map_type 7 into func bpf_map_lookup_elem")
+__naked void map_lookup_in_stack_trace(void)
+{
+	asm volatile ("					\
+	r1 = 0;						\
+	*(u64*)(r10 - 8) = r1;				\
+	r2 = r10;					\
+	r2 += -8;					\
+	r1 = %[map_stacktrace] ll;			\
+	call %[bpf_map_lookup_elem];			\
+	exit;						\
+"	:
+	: __imm(bpf_map_lookup_elem),
+	  __imm_addr(map_stacktrace)
+	: __clobber_all);
+}
+
+SEC("socket")
+__description("prevent map lookup in prog array")
+__failure __msg("cannot pass map_type 3 into func bpf_map_lookup_elem")
+__failure_unpriv
+__naked void map_lookup_in_prog_array(void)
+{
+	asm volatile ("					\
+	r1 = 0;						\
+	*(u64*)(r10 - 8) = r1;				\
+	r2 = r10;					\
+	r2 += -8;					\
+	r1 = %[map_prog2_socket] ll;			\
+	call %[bpf_map_lookup_elem];			\
+	exit;						\
+"	:
+	: __imm(bpf_map_lookup_elem),
+	  __imm_addr(map_prog2_socket)
+	: __clobber_all);
+}
+
+char _license[] SEC("license") = "GPL";