diff mbox series

[v2,bpf-next,04/13] bpf: add register bounds sanity checks and sanitization

Message ID 20231112010609.848406-5-andrii@kernel.org (mailing list archive)
State Accepted
Commit 5f99f312bd3bedb3b266b0d26376a8c500cdc97f
Delegated to: BPF
Headers show
Series BPF register bounds range vs range support | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 2930 this patch: 2930
netdev/cc_maintainers warning 8 maintainers not CCed: jolsa@kernel.org john.fastabend@gmail.com sdf@google.com yonghong.song@linux.dev martin.lau@linux.dev song@kernel.org haoluo@google.com kpsingh@kernel.org
netdev/build_clang success Errors and warnings before: 1298 this patch: 1298
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 3014 this patch: 3014
netdev/checkpatch warning CHECK: Prefer using the BIT macro WARNING: Statements should start on a tabstop WARNING: line length of 83 exceeds 80 columns WARNING: line length of 84 exceeds 80 columns WARNING: line length of 95 exceeds 80 columns WARNING: quoted string split across lines WARNING: suspect code indent for conditional statements (8, 20)
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-VM_Test-0 success Logs for Lint
bpf/vmtest-bpf-next-VM_Test-1 success Logs for ShellCheck
bpf/vmtest-bpf-next-VM_Test-2 success Logs for Validate matrix.py
bpf/vmtest-bpf-next-VM_Test-3 success Logs for aarch64-gcc / build / build for aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-8 success Logs for aarch64-gcc / veristat
bpf/vmtest-bpf-next-VM_Test-4 success Logs for aarch64-gcc / test (test_maps, false, 360) / test_maps on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-7 success Logs for aarch64-gcc / test (test_verifier, false, 360) / test_verifier on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-5 success Logs for aarch64-gcc / test (test_progs, false, 360) / test_progs on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-6 success Logs for aarch64-gcc / test (test_progs_no_alu32, false, 360) / test_progs_no_alu32 on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-9 success Logs for s390x-gcc / build / build for s390x with gcc
bpf/vmtest-bpf-next-VM_Test-14 success Logs for s390x-gcc / veristat
bpf/vmtest-bpf-next-VM_Test-15 success Logs for set-matrix
bpf/vmtest-bpf-next-VM_Test-16 success Logs for x86_64-gcc / build / build for x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-17 success Logs for x86_64-gcc / test (test_maps, false, 360) / test_maps on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-18 success Logs for x86_64-gcc / test (test_progs, false, 360) / test_progs on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-19 success Logs for x86_64-gcc / test (test_progs_no_alu32, false, 360) / test_progs_no_alu32 on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-20 success Logs for x86_64-gcc / test (test_progs_no_alu32_parallel, true, 30) / test_progs_no_alu32_parallel on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-21 success Logs for x86_64-gcc / test (test_progs_parallel, true, 30) / test_progs_parallel on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-22 success Logs for x86_64-gcc / test (test_verifier, false, 360) / test_verifier on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-23 success Logs for x86_64-gcc / veristat / veristat on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-24 success Logs for x86_64-llvm-16 / build / build for x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-25 success Logs for x86_64-llvm-16 / test (test_maps, false, 360) / test_maps on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-26 success Logs for x86_64-llvm-16 / test (test_progs, false, 360) / test_progs on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-27 success Logs for x86_64-llvm-16 / test (test_progs_no_alu32, false, 360) / test_progs_no_alu32 on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-28 success Logs for x86_64-llvm-16 / test (test_verifier, false, 360) / test_verifier on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-29 success Logs for x86_64-llvm-16 / veristat
bpf/vmtest-bpf-next-VM_Test-13 success Logs for s390x-gcc / test (test_verifier, false, 360) / test_verifier on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-12 success Logs for s390x-gcc / test (test_progs_no_alu32, false, 360) / test_progs_no_alu32 on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-11 success Logs for s390x-gcc / test (test_progs, false, 360) / test_progs on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-10 success Logs for s390x-gcc / test (test_maps, false, 360) / test_maps on s390x with gcc
bpf/vmtest-bpf-next-PR fail merge-conflict

Commit Message

Andrii Nakryiko Nov. 12, 2023, 1:06 a.m. UTC 
Add simple sanity checks that validate well-formed ranges (min <= max)
across u64, s64, u32, and s32 ranges. Also for cases when the value is
constant (either 64-bit or 32-bit), we validate that ranges and tnums
are in agreement.

These bounds checks are performed at the end of BPF_ALU/BPF_ALU64
operations, on conditional jumps, and for LDX instructions (where subreg
zero/sign extension is probably the most important to check). This
covers most of the interesting cases.

Also, we validate the sanity of the return register when manually
adjusting it for some special helpers.

By default, sanity violation will trigger a warning in verifier log and
resetting register bounds to "unbounded" ones. But to aid development
and debugging, BPF_F_TEST_SANITY_STRICT flag is added, which will
trigger hard failure of verification with -EFAULT on register bounds
violations. This allows selftests to catch such issues. veristat will
also gain a CLI option to enable this behavior.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 include/linux/bpf_verifier.h   |   1 +
 include/uapi/linux/bpf.h       |   3 +
 kernel/bpf/syscall.c           |   3 +-
 kernel/bpf/verifier.c          | 117 ++++++++++++++++++++++++++-------
 tools/include/uapi/linux/bpf.h |   3 +
 5 files changed, 101 insertions(+), 26 deletions(-)

Comments

Shung-Hsi Yu Nov. 13, 2023, 4:53 a.m. UTC | #1 
On Sat, Nov 11, 2023 at 05:06:00PM -0800, Andrii Nakryiko wrote:
> Add simple sanity checks that validate well-formed ranges (min <= max)
> across u64, s64, u32, and s32 ranges. Also for cases when the value is
> constant (either 64-bit or 32-bit), we validate that ranges and tnums
> are in agreement.
> 
> These bounds checks are performed at the end of BPF_ALU/BPF_ALU64
> operations, on conditional jumps, and for LDX instructions (where subreg
> zero/sign extension is probably the most important to check). This
> covers most of the interesting cases.
> 
> Also, we validate the sanity of the return register when manually
> adjusting it for some special helpers.
> 
> By default, sanity violation will trigger a warning in verifier log and
> resetting register bounds to "unbounded" ones. But to aid development
> and debugging, BPF_F_TEST_SANITY_STRICT flag is added, which will
> trigger hard failure of verification with -EFAULT on register bounds
> violations. This allows selftests to catch such issues. veristat will
> also gain a CLI option to enable this behavior.
> 
> Acked-by: Eduard Zingerman <eddyz87@gmail.com>
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Alexei Starovoitov Nov. 15, 2023, 8:25 p.m. UTC | #2 
On Sat, Nov 11, 2023 at 5:06 PM Andrii Nakryiko <andrii@kernel.org> wrote:
>
>
> By default, sanity violation will trigger a warning in verifier log and
> resetting register bounds to "unbounded" ones. But to aid development
> and debugging, BPF_F_TEST_SANITY_STRICT flag is added, which will
> trigger hard failure of verification with -EFAULT on register bounds
> violations. This allows selftests to catch such issues. veristat will
> also gain a CLI option to enable this behavior.
...
> +       bool test_sanity_strict;        /* fail verification on sanity violations */
...
> +/* The verifier internal test flag. Behavior is undefined */
> +#define BPF_F_TEST_SANITY_STRICT       (1U << 7)

Applied, but please follow up with a rename.

The name of the flag here in uapi and in the "veristat --test-sanity"
will be a subject of bad jokes.
The flag is asking the verifier to test its own sanity?
Can the verifier go insane?
Let's call it TEST_RANGE_ACCOUNTING or something.
I'm guessing you didn't qualify it with 'range' to reuse it
in the future for other 'sanity' checks?
We can add another flag later.
Like BPF_F_TEST_STATE_FREQ is pretty specific and it's a good thing.
I think being specific like BPF_F_TEST_RANGE_TRACKING or
RANGE_ACCOUNTING is better long term.
Andrii Nakryiko Nov. 15, 2023, 10:06 p.m. UTC | #3 
On Wed, Nov 15, 2023 at 3:25 PM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Sat, Nov 11, 2023 at 5:06 PM Andrii Nakryiko <andrii@kernel.org> wrote:
> >
> >
> > By default, sanity violation will trigger a warning in verifier log and
> > resetting register bounds to "unbounded" ones. But to aid development
> > and debugging, BPF_F_TEST_SANITY_STRICT flag is added, which will
> > trigger hard failure of verification with -EFAULT on register bounds
> > violations. This allows selftests to catch such issues. veristat will
> > also gain a CLI option to enable this behavior.
> ...
> > +       bool test_sanity_strict;        /* fail verification on sanity violations */
> ...
> > +/* The verifier internal test flag. Behavior is undefined */
> > +#define BPF_F_TEST_SANITY_STRICT       (1U << 7)
>
> Applied, but please follow up with a rename.
>
> The name of the flag here in uapi and in the "veristat --test-sanity"
> will be a subject of bad jokes.
> The flag is asking the verifier to test its own sanity?
> Can the verifier go insane?
> Let's call it TEST_RANGE_ACCOUNTING or something.
> I'm guessing you didn't qualify it with 'range' to reuse it
> in the future for other 'sanity' checks?
> We can add another flag later.
> Like BPF_F_TEST_STATE_FREQ is pretty specific and it's a good thing.
> I think being specific like BPF_F_TEST_RANGE_TRACKING or
> RANGE_ACCOUNTING is better long term.

Sure, I like BPF_F_TEST_RANGE_TRACKING_STRICT. Or you want to drop the
_STRICT suffix? We can also do something like
BPF_F_TEST_REG_INVARIANTS_STRICT or something to keep it a bit more
generic?
Alexei Starovoitov Nov. 16, 2023, 7:37 p.m. UTC | #4 
On Wed, Nov 15, 2023 at 2:07 PM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Wed, Nov 15, 2023 at 3:25 PM Alexei Starovoitov
> <alexei.starovoitov@gmail.com> wrote:
> >
> > On Sat, Nov 11, 2023 at 5:06 PM Andrii Nakryiko <andrii@kernel.org> wrote:
> > >
> > >
> > > By default, sanity violation will trigger a warning in verifier log and
> > > resetting register bounds to "unbounded" ones. But to aid development
> > > and debugging, BPF_F_TEST_SANITY_STRICT flag is added, which will
> > > trigger hard failure of verification with -EFAULT on register bounds
> > > violations. This allows selftests to catch such issues. veristat will
> > > also gain a CLI option to enable this behavior.
> > ...
> > > +       bool test_sanity_strict;        /* fail verification on sanity violations */
> > ...
> > > +/* The verifier internal test flag. Behavior is undefined */
> > > +#define BPF_F_TEST_SANITY_STRICT       (1U << 7)
> >
> > Applied, but please follow up with a rename.
> >
> > The name of the flag here in uapi and in the "veristat --test-sanity"
> > will be a subject of bad jokes.
> > The flag is asking the verifier to test its own sanity?
> > Can the verifier go insane?
> > Let's call it TEST_RANGE_ACCOUNTING or something.
> > I'm guessing you didn't qualify it with 'range' to reuse it
> > in the future for other 'sanity' checks?
> > We can add another flag later.
> > Like BPF_F_TEST_STATE_FREQ is pretty specific and it's a good thing.
> > I think being specific like BPF_F_TEST_RANGE_TRACKING or
> > RANGE_ACCOUNTING is better long term.
>
> Sure, I like BPF_F_TEST_RANGE_TRACKING_STRICT. Or you want to drop the
> _STRICT suffix? We can also do something like
> BPF_F_TEST_REG_INVARIANTS_STRICT or something to keep it a bit more
> generic?

Both names sound fine. I prefer without _strict mainly because
I'm confused by its meaning. With _strict it sounds like the verifier
already testing range tracking, but not strict enough.
Whereas without the flag there is no enforcement at all.
diff mbox series

Patch

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 24213a99cc79..402b6bc44a1b 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -602,6 +602,7 @@  struct bpf_verifier_env {
 	int stack_size;			/* number of states to be processed */
 	bool strict_alignment;		/* perform strict pointer alignment checks */
 	bool test_state_freq;		/* test verifier with different pruning frequency */
+	bool test_sanity_strict;	/* fail verification on sanity violations */
 	struct bpf_verifier_state *cur_state; /* current verifier state */
 	struct bpf_verifier_state_list **explored_states; /* search pruning optimization */
 	struct bpf_verifier_state_list *free_list;
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 7cf8bcf9f6a2..8a5855fcee69 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1200,6 +1200,9 @@  enum bpf_perf_event_type {
  */
 #define BPF_F_XDP_DEV_BOUND_ONLY	(1U << 6)
 
+/* The verifier internal test flag. Behavior is undefined */
+#define BPF_F_TEST_SANITY_STRICT	(1U << 7)
+
 /* link_create.kprobe_multi.flags used in LINK_CREATE command for
  * BPF_TRACE_KPROBE_MULTI attach type to create return probe.
  */
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 0ed286b8a0f0..f266e03ba342 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2573,7 +2573,8 @@  static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
 				 BPF_F_SLEEPABLE |
 				 BPF_F_TEST_RND_HI32 |
 				 BPF_F_XDP_HAS_FRAGS |
-				 BPF_F_XDP_DEV_BOUND_ONLY))
+				 BPF_F_XDP_DEV_BOUND_ONLY |
+				 BPF_F_TEST_SANITY_STRICT))
 		return -EINVAL;
 
 	if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) &&
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 65570eedfe88..e7edacf86e0f 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2615,6 +2615,56 @@  static void reg_bounds_sync(struct bpf_reg_state *reg)
 	__update_reg_bounds(reg);
 }
 
+static int reg_bounds_sanity_check(struct bpf_verifier_env *env,
+				   struct bpf_reg_state *reg, const char *ctx)
+{
+	const char *msg;
+
+	if (reg->umin_value > reg->umax_value ||
+	    reg->smin_value > reg->smax_value ||
+	    reg->u32_min_value > reg->u32_max_value ||
+	    reg->s32_min_value > reg->s32_max_value) {
+		    msg = "range bounds violation";
+		    goto out;
+	}
+
+	if (tnum_is_const(reg->var_off)) {
+		u64 uval = reg->var_off.value;
+		s64 sval = (s64)uval;
+
+		if (reg->umin_value != uval || reg->umax_value != uval ||
+		    reg->smin_value != sval || reg->smax_value != sval) {
+			msg = "const tnum out of sync with range bounds";
+			goto out;
+		}
+	}
+
+	if (tnum_subreg_is_const(reg->var_off)) {
+		u32 uval32 = tnum_subreg(reg->var_off).value;
+		s32 sval32 = (s32)uval32;
+
+		if (reg->u32_min_value != uval32 || reg->u32_max_value != uval32 ||
+		    reg->s32_min_value != sval32 || reg->s32_max_value != sval32) {
+			msg = "const subreg tnum out of sync with range bounds";
+			goto out;
+		}
+	}
+
+	return 0;
+out:
+	verbose(env, "REG SANITY VIOLATION (%s): %s u64=[%#llx, %#llx] "
+		"s64=[%#llx, %#llx] u32=[%#x, %#x] s32=[%#x, %#x] var_off=(%#llx, %#llx)\n",
+		ctx, msg, reg->umin_value, reg->umax_value,
+		reg->smin_value, reg->smax_value,
+		reg->u32_min_value, reg->u32_max_value,
+		reg->s32_min_value, reg->s32_max_value,
+		reg->var_off.value, reg->var_off.mask);
+	if (env->test_sanity_strict)
+		return -EFAULT;
+	__mark_reg_unbounded(reg);
+	return 0;
+}
+
 static bool __reg32_bound_s64(s32 a)
 {
 	return a >= 0 && a <= S32_MAX;
@@ -9982,14 +10032,15 @@  static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
 	return 0;
 }
 
-static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,
-				   int func_id,
-				   struct bpf_call_arg_meta *meta)
+static int do_refine_retval_range(struct bpf_verifier_env *env,
+				  struct bpf_reg_state *regs, int ret_type,
+				  int func_id,
+				  struct bpf_call_arg_meta *meta)
 {
 	struct bpf_reg_state *ret_reg = &regs[BPF_REG_0];
 
 	if (ret_type != RET_INTEGER)
-		return;
+		return 0;
 
 	switch (func_id) {
 	case BPF_FUNC_get_stack:
@@ -10015,6 +10066,8 @@  static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,
 		reg_bounds_sync(ret_reg);
 		break;
 	}
+
+	return reg_bounds_sanity_check(env, ret_reg, "retval");
 }
 
 static int
@@ -10666,7 +10719,9 @@  static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
 		regs[BPF_REG_0].ref_obj_id = id;
 	}
 
-	do_refine_retval_range(regs, fn->ret_type, func_id, &meta);
+	err = do_refine_retval_range(env, regs, fn->ret_type, func_id, &meta);
+	if (err)
+		return err;
 
 	err = check_map_func_compatibility(env, meta.map_ptr, func_id);
 	if (err)
@@ -14166,13 +14221,12 @@  static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
 
 		/* check dest operand */
 		err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
+		err = err ?: adjust_reg_min_max_vals(env, insn);
 		if (err)
 			return err;
-
-		return adjust_reg_min_max_vals(env, insn);
 	}
 
-	return 0;
+	return reg_bounds_sanity_check(env, &regs[insn->dst_reg], "alu");
 }
 
 static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
@@ -14653,18 +14707,21 @@  static void regs_refine_cond_op(struct bpf_reg_state *reg1, struct bpf_reg_state
  * Technically we can do similar adjustments for pointers to the same object,
  * but we don't support that right now.
  */
-static void reg_set_min_max(struct bpf_reg_state *true_reg1,
-			    struct bpf_reg_state *true_reg2,
-			    struct bpf_reg_state *false_reg1,
-			    struct bpf_reg_state *false_reg2,
-			    u8 opcode, bool is_jmp32)
+static int reg_set_min_max(struct bpf_verifier_env *env,
+			   struct bpf_reg_state *true_reg1,
+			   struct bpf_reg_state *true_reg2,
+			   struct bpf_reg_state *false_reg1,
+			   struct bpf_reg_state *false_reg2,
+			   u8 opcode, bool is_jmp32)
 {
+	int err;
+
 	/* If either register is a pointer, we can't learn anything about its
 	 * variable offset from the compare (unless they were a pointer into
 	 * the same object, but we don't bother with that).
 	 */
 	if (false_reg1->type != SCALAR_VALUE || false_reg2->type != SCALAR_VALUE)
-		return;
+		return 0;
 
 	/* fallthrough (FALSE) branch */
 	regs_refine_cond_op(false_reg1, false_reg2, rev_opcode(opcode), is_jmp32);
@@ -14675,6 +14732,12 @@  static void reg_set_min_max(struct bpf_reg_state *true_reg1,
 	regs_refine_cond_op(true_reg1, true_reg2, opcode, is_jmp32);
 	reg_bounds_sync(true_reg1);
 	reg_bounds_sync(true_reg2);
+
+	err = reg_bounds_sanity_check(env, true_reg1, "true_reg1");
+	err = err ?: reg_bounds_sanity_check(env, true_reg2, "true_reg2");
+	err = err ?: reg_bounds_sanity_check(env, false_reg1, "false_reg1");
+	err = err ?: reg_bounds_sanity_check(env, false_reg2, "false_reg2");
+	return err;
 }
 
 static void mark_ptr_or_null_reg(struct bpf_func_state *state,
@@ -14968,15 +15031,20 @@  static int check_cond_jmp_op(struct bpf_verifier_env *env,
 	other_branch_regs = other_branch->frame[other_branch->curframe]->regs;
 
 	if (BPF_SRC(insn->code) == BPF_X) {
-		reg_set_min_max(&other_branch_regs[insn->dst_reg],
-				&other_branch_regs[insn->src_reg],
-				dst_reg, src_reg, opcode, is_jmp32);
+		err = reg_set_min_max(env,
+				      &other_branch_regs[insn->dst_reg],
+				      &other_branch_regs[insn->src_reg],
+				      dst_reg, src_reg, opcode, is_jmp32);
 	} else /* BPF_SRC(insn->code) == BPF_K */ {
-		reg_set_min_max(&other_branch_regs[insn->dst_reg],
-				src_reg /* fake one */,
-				dst_reg, src_reg /* same fake one */,
-				opcode, is_jmp32);
+		err = reg_set_min_max(env,
+				      &other_branch_regs[insn->dst_reg],
+				      src_reg /* fake one */,
+				      dst_reg, src_reg /* same fake one */,
+				      opcode, is_jmp32);
 	}
+	if (err)
+		return err;
+
 	if (BPF_SRC(insn->code) == BPF_X &&
 	    src_reg->type == SCALAR_VALUE && src_reg->id &&
 	    !WARN_ON_ONCE(src_reg->id != other_branch_regs[insn->src_reg].id)) {
@@ -17479,10 +17547,8 @@  static int do_check(struct bpf_verifier_env *env)
 					       insn->off, BPF_SIZE(insn->code),
 					       BPF_READ, insn->dst_reg, false,
 					       BPF_MODE(insn->code) == BPF_MEMSX);
-			if (err)
-				return err;
-
-			err = save_aux_ptr_type(env, src_reg_type, true);
+			err = err ?: save_aux_ptr_type(env, src_reg_type, true);
+			err = err ?: reg_bounds_sanity_check(env, &regs[insn->dst_reg], "ldx");
 			if (err)
 				return err;
 		} else if (class == BPF_STX) {
@@ -20769,6 +20835,7 @@  int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3
 
 	if (is_priv)
 		env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;
+	env->test_sanity_strict = attr->prog_flags & BPF_F_TEST_SANITY_STRICT;
 
 	env->explored_states = kvcalloc(state_htab_size(env),
 				       sizeof(struct bpf_verifier_state_list *),
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 7cf8bcf9f6a2..8a5855fcee69 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1200,6 +1200,9 @@  enum bpf_perf_event_type {
  */
 #define BPF_F_XDP_DEV_BOUND_ONLY	(1U << 6)
 
+/* The verifier internal test flag. Behavior is undefined */
+#define BPF_F_TEST_SANITY_STRICT	(1U << 7)
+
 /* link_create.kprobe_multi.flags used in LINK_CREATE command for
  * BPF_TRACE_KPROBE_MULTI attach type to create return probe.
  */