Commit 9d2be44a authored by Joe Stringer's avatar Joe Stringer Committed by Daniel Borkmann
Browse files

bpf: Reuse canonical string formatter for ctx errs 



The array "reg_type_str" provides canonical formatting of register
types, however a couple of places would previously check whether a
register represented the context and write the name "context" directly.
An upcoming commit will add another pointer type to these statements, so
to provide more accurate error messages in the verifier, update these
error messages to use "reg_type_str" instead.

Signed-off-by: default avatarJoe Stringer <joe@wand.net.nz>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent aad2eeaf

kernel/bpf/verifier.c

+3 −4
Original line number Diff line number Diff line
@@ -1763,8 +1763,7 @@ 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, is_ctx_reg(env, insn->dst_reg) ?

			"context" : "packet");

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

		return -EACCES;

	}
@@ -4871,8 +4870,8 @@ static int do_check(struct bpf_verifier_env *env) 
				return err;



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

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

					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]);

				return -EACCES;

			}

tools/testing/selftests/bpf/test_verifier.c

+5 −5
Original line number Diff line number Diff line
@@ -3276,7 +3276,7 @@ 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 context is not allowed",

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

		.result = REJECT,

		.prog_type = BPF_PROG_TYPE_SCHED_CLS,

	},
@@ -3288,7 +3288,7 @@ static struct bpf_test tests[] = { 
				     BPF_REG_0, offsetof(struct __sk_buff, mark), 0),

			BPF_EXIT_INSN(),

		},

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

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

		.result = REJECT,

		.prog_type = BPF_PROG_TYPE_SCHED_CLS,

	},
@@ -5266,7 +5266,7 @@ static struct bpf_test tests[] = { 
		.errstr_unpriv = "R2 leaks addr into mem",

		.result_unpriv = REJECT,

		.result = REJECT,

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

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

	},

	{

		"leak pointer into ctx 2",
@@ -5281,7 +5281,7 @@ static struct bpf_test tests[] = { 
		.errstr_unpriv = "R10 leaks addr into mem",

		.result_unpriv = REJECT,

		.result = REJECT,

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

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

	},

	{

		"leak pointer into ctx 3",
@@ -12230,7 +12230,7 @@ static struct bpf_test tests[] = { 
			BPF_EXIT_INSN(),

		},

		.result = REJECT,

		.errstr = "BPF_XADD stores into R2 packet",

		.errstr = "BPF_XADD stores into R2 ctx",

		.prog_type = BPF_PROG_TYPE_XDP,

	},

	{

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