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

Alexei Starovoitov says:

====================
pull-request: bpf-next 2023-07-13

We've added 67 non-merge commits during the last 15 day(s) which contain
a total of 106 files changed, 4444 insertions(+), 619 deletions(-).

The main changes are:

1) Fix bpftool build in presence of stale vmlinux.h,
   from Alexander Lobakin.

2) Introduce bpf_me_mcache_free_rcu() and fix OOM under stress,
   from Alexei Starovoitov.

3) Teach verifier actual bounds of bpf_get_smp_processor_id()
   and fix perf+libbpf issue related to custom section handling,
   from Andrii Nakryiko.

4) Introduce bpf map element count, from Anton Protopopov.

5) Check skb ownership against full socket, from Kui-Feng Lee.

6) Support for up to 12 arguments in BPF trampoline, from Menglong Dong.

7) Export rcu_request_urgent_qs_task, from Paul E. McKenney.

8) Fix BTF walking of unions, from Yafang Shao.

9) Extend link_info for kprobe_multi and perf_event links,
   from Yafang Shao.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (67 commits)
  selftests/bpf: Add selftest for PTR_UNTRUSTED
  bpf: Fix an error in verifying a field in a union
  selftests/bpf: Add selftests for nested_trust
  bpf: Fix an error around PTR_UNTRUSTED
  selftests/bpf: add testcase for TRACING with 6+ arguments
  bpf, x86: allow function arguments up to 12 for TRACING
  bpf, x86: save/restore regs with BPF_DW size
  bpftool: Use "fallthrough;" keyword instead of comments
  bpf: Add object leak check.
  bpf: Convert bpf_cpumask to bpf_mem_cache_free_rcu.
  bpf: Introduce bpf_mem_free_rcu() similar to kfree_rcu().
  selftests/bpf: Improve test coverage of bpf_mem_alloc.
  rcu: Export rcu_request_urgent_qs_task()
  bpf: Allow reuse from waiting_for_gp_ttrace list.
  bpf: Add a hint to allocated objects.
  bpf: Change bpf_mem_cache draining process.
  bpf: Further refactor alloc_bulk().
  bpf: Factor out inc/dec of active flag into helpers.
  bpf: Refactor alloc_bulk().
  bpf: Let free_all() return the number of freed elements.
  ...
====================

Link: https://lore.kernel.org/r/20230714020910.80794-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 31 insertions, 11 deletions

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 930b5555cfd3..0b9da95331d7 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -25,6 +25,7 @@
 #include <linux/btf_ids.h>
 #include <linux/poison.h>
 #include <linux/module.h>
+#include <linux/cpumask.h>
 
 #include "disasm.h"
 
@@ -6067,6 +6068,11 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
 				   type_is_rcu_or_null(env, reg, field_name, btf_id)) {
 				/* __rcu tagged pointers can be NULL */
 				flag |= MEM_RCU | PTR_MAYBE_NULL;
+
+				/* We always trust them */
+				if (type_is_rcu_or_null(env, reg, field_name, btf_id) &&
+				    flag & PTR_UNTRUSTED)
+					flag &= ~PTR_UNTRUSTED;
 			} else if (flag & (MEM_PERCPU | MEM_USER)) {
 				/* keep as-is */
 			} else {
@@ -9117,19 +9123,33 @@ static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,
 {
 	struct bpf_reg_state *ret_reg = &regs[BPF_REG_0];
 
-	if (ret_type != RET_INTEGER ||
-	    (func_id != BPF_FUNC_get_stack &&
-	     func_id != BPF_FUNC_get_task_stack &&
-	     func_id != BPF_FUNC_probe_read_str &&
-	     func_id != BPF_FUNC_probe_read_kernel_str &&
-	     func_id != BPF_FUNC_probe_read_user_str))
+	if (ret_type != RET_INTEGER)
 		return;
 
-	ret_reg->smax_value = meta->msize_max_value;
-	ret_reg->s32_max_value = meta->msize_max_value;
-	ret_reg->smin_value = -MAX_ERRNO;
-	ret_reg->s32_min_value = -MAX_ERRNO;
-	reg_bounds_sync(ret_reg);
+	switch (func_id) {
+	case BPF_FUNC_get_stack:
+	case BPF_FUNC_get_task_stack:
+	case BPF_FUNC_probe_read_str:
+	case BPF_FUNC_probe_read_kernel_str:
+	case BPF_FUNC_probe_read_user_str:
+		ret_reg->smax_value = meta->msize_max_value;
+		ret_reg->s32_max_value = meta->msize_max_value;
+		ret_reg->smin_value = -MAX_ERRNO;
+		ret_reg->s32_min_value = -MAX_ERRNO;
+		reg_bounds_sync(ret_reg);
+		break;
+	case BPF_FUNC_get_smp_processor_id:
+		ret_reg->umax_value = nr_cpu_ids - 1;
+		ret_reg->u32_max_value = nr_cpu_ids - 1;
+		ret_reg->smax_value = nr_cpu_ids - 1;
+		ret_reg->s32_max_value = nr_cpu_ids - 1;
+		ret_reg->umin_value = 0;
+		ret_reg->u32_min_value = 0;
+		ret_reg->smin_value = 0;
+		ret_reg->s32_min_value = 0;
+		reg_bounds_sync(ret_reg);
+		break;
+	}
 }
 
 static int