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Commit 2a159c6f authored by Daniel Borkmann's avatar Daniel Borkmann Committed by Alexei Starovoitov
Browse files

bpf, verifier: fix register type dump in xadd and st 



Using reg_type_str[insn->dst_reg] is incorrect since insn->dst_reg
contains the register number but not the actual register type. Add
a small reg_state() helper and use it to get to the type. Also fix
up the test_verifier test cases that have an incorrect errstr.

Fixes: 9d2be44a ("bpf: Reuse canonical string formatter for ctx errs")
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent c16ee04c

kernel/bpf/verifier.c

+13 −6
Original line number Diff line number Diff line
@@ -1528,14 +1528,19 @@ static bool __is_pointer_value(bool allow_ptr_leaks, 
	return reg->type != SCALAR_VALUE;

}



static struct bpf_reg_state *reg_state(struct bpf_verifier_env *env, int regno)

{

	return cur_regs(env) + regno;

}



static bool is_pointer_value(struct bpf_verifier_env *env, int regno)

{

	return __is_pointer_value(env->allow_ptr_leaks, cur_regs(env) + regno);

	return __is_pointer_value(env->allow_ptr_leaks, reg_state(env, regno));

}



static bool is_ctx_reg(struct bpf_verifier_env *env, int regno)

{

	const struct bpf_reg_state *reg = cur_regs(env) + regno;

	const struct bpf_reg_state *reg = reg_state(env, regno);



	return reg->type == PTR_TO_CTX ||

	       reg->type == PTR_TO_SOCKET;
@@ -1543,7 +1548,7 @@ static bool is_ctx_reg(struct bpf_verifier_env *env, int regno) 


static bool is_pkt_reg(struct bpf_verifier_env *env, int regno)

{

	const struct bpf_reg_state *reg = cur_regs(env) + regno;

	const struct bpf_reg_state *reg = reg_state(env, regno);



	return type_is_pkt_pointer(reg->type);

}
@@ -1958,7 +1963,8 @@ static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_ins 
	if (is_ctx_reg(env, insn->dst_reg) ||

	    is_pkt_reg(env, insn->dst_reg)) {

		verbose(env, "BPF_XADD stores into R%d %s is not allowed\n",

			insn->dst_reg, reg_type_str[insn->dst_reg]);

			insn->dst_reg,

			reg_type_str[reg_state(env, insn->dst_reg)->type]);

		return -EACCES;

	}
@@ -1983,7 +1989,7 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno, 
				int access_size, bool zero_size_allowed,

				struct bpf_call_arg_meta *meta)

{

	struct bpf_reg_state *reg = cur_regs(env) + regno;

	struct bpf_reg_state *reg = reg_state(env, regno);

	struct bpf_func_state *state = func(env, reg);

	int off, i, slot, spi;
@@ -5264,7 +5270,8 @@ static int do_check(struct bpf_verifier_env *env) 


			if (is_ctx_reg(env, insn->dst_reg)) {

				verbose(env, "BPF_ST stores into R%d %s is not allowed\n",

					insn->dst_reg, reg_type_str[insn->dst_reg]);

					insn->dst_reg,

					reg_type_str[reg_state(env, insn->dst_reg)->type]);

				return -EACCES;

			}

tools/testing/selftests/bpf/test_verifier.c

+5 −5
Original line number Diff line number Diff line
@@ -3430,7 +3430,7 @@ static struct bpf_test tests[] = { 
			BPF_ST_MEM(BPF_DW, BPF_REG_1, offsetof(struct __sk_buff, mark), 0),

			BPF_EXIT_INSN(),

		},

		.errstr = "BPF_ST stores into R1 inv is not allowed",

		.errstr = "BPF_ST stores into R1 ctx is not allowed",

		.result = REJECT,

		.prog_type = BPF_PROG_TYPE_SCHED_CLS,

	},
@@ -3442,7 +3442,7 @@ static struct bpf_test tests[] = { 
				     BPF_REG_0, offsetof(struct __sk_buff, mark), 0),

			BPF_EXIT_INSN(),

		},

		.errstr = "BPF_XADD stores into R1 inv is not allowed",

		.errstr = "BPF_XADD stores into R1 ctx is not allowed",

		.result = REJECT,

		.prog_type = BPF_PROG_TYPE_SCHED_CLS,

	},
@@ -5670,7 +5670,7 @@ static struct bpf_test tests[] = { 
		.errstr_unpriv = "R2 leaks addr into mem",

		.result_unpriv = REJECT,

		.result = REJECT,

		.errstr = "BPF_XADD stores into R1 inv is not allowed",

		.errstr = "BPF_XADD stores into R1 ctx is not allowed",

	},

	{

		"leak pointer into ctx 2",
@@ -5685,7 +5685,7 @@ static struct bpf_test tests[] = { 
		.errstr_unpriv = "R10 leaks addr into mem",

		.result_unpriv = REJECT,

		.result = REJECT,

		.errstr = "BPF_XADD stores into R1 inv is not allowed",

		.errstr = "BPF_XADD stores into R1 ctx is not allowed",

	},

	{

		"leak pointer into ctx 3",
@@ -12634,7 +12634,7 @@ static struct bpf_test tests[] = { 
			BPF_EXIT_INSN(),

		},

		.result = REJECT,

		.errstr = "BPF_XADD stores into R2 ctx",

		.errstr = "BPF_XADD stores into R2 pkt is not allowed",

		.prog_type = BPF_PROG_TYPE_XDP,

	},

	{