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BPF fixes and tests

PATCH Applied Daniel Borkmann 5 participants 9 messages Nov 1, 2018 – Nov 2, 2018

Subsystems (6)
Networking Network drivers Kselftest BPF +2 more subsystems
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Daniel Borkmann

author maintainer
#0 lore raw

cover BPF fixes and tests

The series contains two fixes in BPF core and test cases. For details please see individual patches. Thanks!

Daniel Borkmann (4):
bpf: fix partial copy of map_ptr when dst is scalar
bpf: don't set id on after map lookup with ptr_to_map_val return
bpf: add various test cases to test_verifier
bpf: test make sure to run unpriv test cases in test_verifier

 include/linux/bpf_verifier.h                |   3 +
 kernel/bpf/verifier.c                       |  21 +-
 tools/testing/selftests/bpf/test_verifier.c | 321 +++++++++++++++++++++++++---
 3 files changed, 305 insertions(+), 40 deletions(-)
Signature · 1 line
2.9.5
author maintainer
#1 lore raw

PATCH 1/4 bpf: fix partial copy of map_ptr when dst is scalar

ALU operations on pointers such as scalar_reg += map_value_ptr are handled in adjust_ptr_min_max_vals(). Problem is however that map_ptr and range in the register state share a union, so transferring state through dst_reg->range = ptr_reg->range is just buggy as any new map_ptr in the dst_reg is then truncated (or null) for subsequent checks. Fix this by adding a raw member and use it for copying state over to dst_reg.

Fixes f1174f77b50c ("bpf/verifier: rework value tracking")
Signed-off-by Daniel Borkmann <[email protected]>
Cc Edward Cree <[email protected]>
Acked-by Alexei Starovoitov <[email protected]>
---
 include/linux/bpf_verifier.h |  3 +++
 kernel/bpf/verifier.c        | 10 ++++++----
 2 files changed, 9 insertions(+), 4 deletions(-)
include/linux/bpf_verifier.h +3 -0
index 9e8056e..d93e897 100644
@@ -51,6 +51,9 @@ struct bpf_reg_state {
 		 *   PTR_TO_MAP_VALUE_OR_NULL
 		 */
 		struct bpf_map *map_ptr;
+
+		/* Max size from any of the above. */
+		unsigned long raw;
 	};
 	/* Fixed part of pointer offset, pointer types only */
 	s32 off;
kernel/bpf/verifier.c +6 -4
index 171a2c8..774fa40 100644
@@ -3046,7 +3046,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
 			dst_reg->umax_value = umax_ptr;
 			dst_reg->var_off = ptr_reg->var_off;
 			dst_reg->off = ptr_reg->off + smin_val;
-			dst_reg->range = ptr_reg->range;
+			dst_reg->raw = ptr_reg->raw;
 			break;
 		}
 		/* A new variable offset is created.  Note that off_reg->off

@@ -3076,10 +3076,11 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
 		}
 		dst_reg->var_off = tnum_add(ptr_reg->var_off, off_reg->var_off);
 		dst_reg->off = ptr_reg->off;
+		dst_reg->raw = ptr_reg->raw;
 		if (reg_is_pkt_pointer(ptr_reg)) {
 			dst_reg->id = ++env->id_gen;
 			/* something was added to pkt_ptr, set range to zero */
-			dst_reg->range = 0;
+			dst_reg->raw = 0;
 		}
 		break;
 	case BPF_SUB:

@@ -3108,7 +3109,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
 			dst_reg->var_off = ptr_reg->var_off;
 			dst_reg->id = ptr_reg->id;
 			dst_reg->off = ptr_reg->off - smin_val;
-			dst_reg->range = ptr_reg->range;
+			dst_reg->raw = ptr_reg->raw;
 			break;
 		}
 		/* A new variable offset is created.  If the subtrahend is known

@@ -3134,11 +3135,12 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
 		}
 		dst_reg->var_off = tnum_sub(ptr_reg->var_off, off_reg->var_off);
 		dst_reg->off = ptr_reg->off;
+		dst_reg->raw = ptr_reg->raw;
 		if (reg_is_pkt_pointer(ptr_reg)) {
 			dst_reg->id = ++env->id_gen;
 			/* something was added to pkt_ptr, set range to zero */
 			if (smin_val < 0)
-				dst_reg->range = 0;
+				dst_reg->raw = 0;
 		}
 		break;
 	case BPF_AND:
Signature · 1 line
2.9.5
Acked-by on v1 1/4
#2 lore raw

Re: [PATCH bpf 1/4] bpf: fix partial copy of map_ptr when dst is scalar

Quoted 8 lines · Daniel Borkmann

ALU operations on pointers such as scalar_reg += map_value_ptr are handled in adjust_ptr_min_max_vals(). Problem is however that map_ptr and range in the register state share a union, so transferring state through dst_reg->range = ptr_reg->range is just buggy as any new map_ptr in the dst_reg is then truncated (or null) for subsequent checks. Fix this by adding a raw member and use it for copying state over to dst_reg.

Quoted 5 lines
Fixes f1174f77b50c ("bpf/verifier: rework value tracking")
Signed-off-by Daniel Borkmann <[email protected]>
Cc Edward Cree <[email protected]>
Acked-by Alexei Starovoitov <[email protected]>

---

Acked-by Edward Cree <[email protected]>

(though I apparently missed the 63-minute window to hit the git record...)

#3 lore raw

Re: [PATCH bpf 1/4] bpf: fix partial copy of map_ptr when dst is scalar

Em Thu, Nov 01, 2018 at 07:17:29PM +0000, Edward Cree escreveu:

Quoted 9 lines · Daniel Borkmann
Quoted 8 lines

ALU operations on pointers such as scalar_reg += map_value_ptr are handled in adjust_ptr_min_max_vals(). Problem is however that map_ptr and range in the register state share a union, so transferring state through dst_reg->range = ptr_reg->range is just buggy as any new map_ptr in the dst_reg is then truncated (or null) for subsequent checks. Fix this by adding a raw member and use it for copying state over to dst_reg.

Quoted 7 lines
Quoted 5 lines
Fixes f1174f77b50c ("bpf/verifier: rework value tracking")
Signed-off-by Daniel Borkmann <[email protected]>
Cc Edward Cree <[email protected]>
Acked-by Alexei Starovoitov <[email protected]>

---

Acked-by Edward Cree <[email protected]>

(though I apparently missed the 63-minute window to hit the git record...)

Those guys are fast! :-)

- Arnaldo

author maintainer
#4 lore raw

PATCH 2/4 bpf: don't set id on after map lookup with ptr_to_map_val return

In reply to Daniel Borkmann

In the verifier there is no such semantics where registers with PTR_TO_MAP_VALUE type have an id assigned to them. This is only used in PTR_TO_MAP_VALUE_OR_NULL and later on nullified once the test against NULL has been pattern matched and type transformed into PTR_TO_MAP_VALUE.

Fixes 3e6a4b3e0289 ("bpf/verifier: introduce BPF_PTR_TO_MAP_VALUE")
Signed-off-by Daniel Borkmann <[email protected]>
Cc Roman Gushchin <[email protected]>
Acked-by Alexei Starovoitov <[email protected]>
---
 kernel/bpf/verifier.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
kernel/bpf/verifier.c +6 -5
index 774fa40..1971ca32 100644
@@ -2852,10 +2852,6 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
 		regs[BPF_REG_0].type = NOT_INIT;
 	} else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL ||
 		   fn->ret_type == RET_PTR_TO_MAP_VALUE) {
-		if (fn->ret_type == RET_PTR_TO_MAP_VALUE)
-			regs[BPF_REG_0].type = PTR_TO_MAP_VALUE;
-		else
-			regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
 		/* There is no offset yet applied, variable or fixed */
 		mark_reg_known_zero(env, regs, BPF_REG_0);
 		/* remember map_ptr, so that check_map_access()

@@ -2868,7 +2864,12 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
 			return -EINVAL;
 		}
 		regs[BPF_REG_0].map_ptr = meta.map_ptr;
-		regs[BPF_REG_0].id = ++env->id_gen;
+		if (fn->ret_type == RET_PTR_TO_MAP_VALUE) {
+			regs[BPF_REG_0].type = PTR_TO_MAP_VALUE;
+		} else {
+			regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
+			regs[BPF_REG_0].id = ++env->id_gen;
+		}
 	} else if (fn->ret_type == RET_PTR_TO_SOCKET_OR_NULL) {
 		int id = acquire_reference_state(env, insn_idx);
 		if (id < 0)
Signature · 1 line
2.9.5
Acked-by on v1 2/4
#5 lore raw

Re: [PATCH bpf 2/4] bpf: don't set id on after map lookup with ptr_to_map_val return

Quoted 10 lines · Daniel Borkmann

In the verifier there is no such semantics where registers with PTR_TO_MAP_VALUE type have an id assigned to them. This is only used in PTR_TO_MAP_VALUE_OR_NULL and later on nullified once the test against NULL has been pattern matched and type transformed into PTR_TO_MAP_VALUE.

Fixes 3e6a4b3e0289 ("bpf/verifier: introduce BPF_PTR_TO_MAP_VALUE")
Signed-off-by Daniel Borkmann <[email protected]>
Cc Roman Gushchin <[email protected]>
Acked-by Alexei Starovoitov <[email protected]>

Looks good to me.

Acked-by Roman Gushchin <[email protected]>

Thanks!

author maintainer
#6 lore raw

PATCH 3/4 bpf: add various test cases to test_verifier

In reply to Daniel Borkmann

Add some more map related test cases to test_verifier kselftest to improve test coverage. Summary: 1012 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by Daniel Borkmann <[email protected]>
Acked-by Alexei Starovoitov <[email protected]>
---
 tools/testing/selftests/bpf/test_verifier.c | 250 ++++++++++++++++++++++++++++
 1 file changed, 250 insertions(+)
tools/testing/selftests/bpf/test_verifier.c +250 -0
index 36f3d30..4c7445d 100644
@@ -6455,6 +6455,256 @@ static struct bpf_test tests[] = {
 		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
 	},
 	{
+		"map access: known scalar += value_ptr",
+		.insns = {
+			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
+			BPF_MOV64_IMM(BPF_REG_1, 4),
+			BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_0),
+			BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map_array_48b = { 3 },
+		.result = ACCEPT,
+		.retval = 1,
+	},
+	{
+		"map access: value_ptr += known scalar",
+		.insns = {
+			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
+			BPF_MOV64_IMM(BPF_REG_1, 4),
+			BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map_array_48b = { 3 },
+		.result = ACCEPT,
+		.retval = 1,
+	},
+	{
+		"map access: unknown scalar += value_ptr",
+		.insns = {
+			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+			BPF_ALU64_IMM(BPF_AND, BPF_REG_1, 0xf),
+			BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_0),
+			BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map_array_48b = { 3 },
+		.result = ACCEPT,
+		.retval = 1,
+	},
+	{
+		"map access: value_ptr += unknown scalar",
+		.insns = {
+			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+			BPF_ALU64_IMM(BPF_AND, BPF_REG_1, 0xf),
+			BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map_array_48b = { 3 },
+		.result = ACCEPT,
+		.retval = 1,
+	},
+	{
+		"map access: value_ptr += value_ptr",
+		.insns = {
+			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
+			BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_0),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map_array_48b = { 3 },
+		.result = REJECT,
+		.errstr = "R0 pointer += pointer prohibited",
+	},
+	{
+		"map access: known scalar -= value_ptr",
+		.insns = {
+			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
+			BPF_MOV64_IMM(BPF_REG_1, 4),
+			BPF_ALU64_REG(BPF_SUB, BPF_REG_1, BPF_REG_0),
+			BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map_array_48b = { 3 },
+		.result = REJECT,
+		.errstr = "R1 tried to subtract pointer from scalar",
+	},
+	{
+		"map access: value_ptr -= known scalar",
+		.insns = {
+			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
+			BPF_MOV64_IMM(BPF_REG_1, 4),
+			BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map_array_48b = { 3 },
+		.result = REJECT,
+		.errstr = "R0 min value is outside of the array range",
+	},
+	{
+		"map access: value_ptr -= known scalar, 2",
+		.insns = {
+			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 5),
+			BPF_MOV64_IMM(BPF_REG_1, 6),
+			BPF_MOV64_IMM(BPF_REG_2, 4),
+			BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
+			BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_2),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map_array_48b = { 3 },
+		.result = ACCEPT,
+		.retval = 1,
+	},
+	{
+		"map access: unknown scalar -= value_ptr",
+		.insns = {
+			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+			BPF_ALU64_IMM(BPF_AND, BPF_REG_1, 0xf),
+			BPF_ALU64_REG(BPF_SUB, BPF_REG_1, BPF_REG_0),
+			BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map_array_48b = { 3 },
+		.result = REJECT,
+		.errstr = "R1 tried to subtract pointer from scalar",
+	},
+	{
+		"map access: value_ptr -= unknown scalar",
+		.insns = {
+			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+			BPF_ALU64_IMM(BPF_AND, BPF_REG_1, 0xf),
+			BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map_array_48b = { 3 },
+		.result = REJECT,
+		.errstr = "R0 min value is negative",
+	},
+	{
+		"map access: value_ptr -= unknown scalar, 2",
+		.insns = {
+			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 8),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+			BPF_ALU64_IMM(BPF_AND, BPF_REG_1, 0xf),
+			BPF_ALU64_IMM(BPF_OR, BPF_REG_1, 0x7),
+			BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+			BPF_ALU64_IMM(BPF_AND, BPF_REG_1, 0x7),
+			BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map_array_48b = { 3 },
+		.result = ACCEPT,
+		.retval = 1,
+	},
+	{
+		"map access: value_ptr -= value_ptr",
+		.insns = {
+			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
+			BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_0),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map_array_48b = { 3 },
+		.result = REJECT,
+		.errstr = "R0 invalid mem access 'inv'",
+		.errstr_unpriv = "R0 pointer -= pointer prohibited",
+	},
+	{
 		"map lookup helper access to map",
 		.insns = {
 			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
Signature · 1 line
2.9.5
author maintainer
#7 lore raw

PATCH 4/4 bpf: test make sure to run unpriv test cases in test_verifier

In reply to Daniel Borkmann

Right now unprivileged tests are never executed as a BPF test run, only loaded. Allow for running them as well so that we can check the outcome and probe for regressions.

Signed-off-by Daniel Borkmann <[email protected]>
Acked-by Alexei Starovoitov <[email protected]>
---
 tools/testing/selftests/bpf/test_verifier.c | 71 ++++++++++++++++-------------
 1 file changed, 40 insertions(+), 31 deletions(-)
tools/testing/selftests/bpf/test_verifier.c +40 -31
index 4c7445d..6f61df6 100644
@@ -76,7 +76,7 @@ struct bpf_test {
 	int fixup_percpu_cgroup_storage[MAX_FIXUPS];
 	const char *errstr;
 	const char *errstr_unpriv;
-	uint32_t retval;
+	uint32_t retval, retval_unpriv;
 	enum {
 		UNDEF,
 		ACCEPT,

@@ -3084,6 +3084,8 @@ static struct bpf_test tests[] = {
 		.fixup_prog1 = { 2 },
 		.result = ACCEPT,
 		.retval = 42,
+		/* Verifier rewrite for unpriv skips tail call here. */
+		.retval_unpriv = 2,
 	},
 	{
 		"stack pointer arithmetic",

@@ -14149,6 +14151,33 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_map_type prog_type,
 	}
 }
 
+static int set_admin(bool admin)
+{
+	cap_t caps;
+	const cap_value_t cap_val = CAP_SYS_ADMIN;
+	int ret = -1;
+
+	caps = cap_get_proc();
+	if (!caps) {
+		perror("cap_get_proc");
+		return -1;
+	}
+	if (cap_set_flag(caps, CAP_EFFECTIVE, 1, &cap_val,
+				admin ? CAP_SET : CAP_CLEAR)) {
+		perror("cap_set_flag");
+		goto out;
+	}
+	if (cap_set_proc(caps)) {
+		perror("cap_set_proc");
+		goto out;
+	}
+	ret = 0;
+out:
+	if (cap_free(caps))
+		perror("cap_free");
+	return ret;
+}
+
 static void do_test_single(struct bpf_test *test, bool unpriv,
 			   int *passes, int *errors)
 {

@@ -14157,6 +14186,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 	struct bpf_insn *prog = test->insns;
 	int map_fds[MAX_NR_MAPS];
 	const char *expected_err;
+	uint32_t expected_val;
 	uint32_t retval;
 	int i, err;
 

@@ -14176,6 +14206,8 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 		       test->result_unpriv : test->result;
 	expected_err = unpriv && test->errstr_unpriv ?
 		       test->errstr_unpriv : test->errstr;
+	expected_val = unpriv && test->retval_unpriv ?
+		       test->retval_unpriv : test->retval;
 
 	reject_from_alignment = fd_prog < 0 &&
 				(test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS) &&

@@ -14209,16 +14241,20 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 		__u8 tmp[TEST_DATA_LEN << 2];
 		__u32 size_tmp = sizeof(tmp);
 
+		if (unpriv)
+			set_admin(true);
 		err = bpf_prog_test_run(fd_prog, 1, test->data,
 					sizeof(test->data), tmp, &size_tmp,
 					&retval, NULL);
+		if (unpriv)
+			set_admin(false);
 		if (err && errno != 524/*ENOTSUPP*/ && errno != EPERM) {
 			printf("Unexpected bpf_prog_test_run error\n");
 			goto fail_log;
 		}
-		if (!err && retval != test->retval &&
-		    test->retval != POINTER_VALUE) {
-			printf("FAIL retval %d != %d\n", retval, test->retval);
+		if (!err && retval != expected_val &&
+		    expected_val != POINTER_VALUE) {
+			printf("FAIL retval %d != %d\n", retval, expected_val);
 			goto fail_log;
 		}
 	}

@@ -14261,33 +14297,6 @@ static bool is_admin(void)
 	return (sysadmin == CAP_SET);
 }
 
-static int set_admin(bool admin)
-{
-	cap_t caps;
-	const cap_value_t cap_val = CAP_SYS_ADMIN;
-	int ret = -1;
-
-	caps = cap_get_proc();
-	if (!caps) {
-		perror("cap_get_proc");
-		return -1;
-	}
-	if (cap_set_flag(caps, CAP_EFFECTIVE, 1, &cap_val,
-				admin ? CAP_SET : CAP_CLEAR)) {
-		perror("cap_set_flag");
-		goto out;
-	}
-	if (cap_set_proc(caps)) {
-		perror("cap_set_proc");
-		goto out;
-	}
-	ret = 0;
-out:
-	if (cap_free(caps))
-		perror("cap_free");
-	return ret;
-}
-
 static void get_unpriv_disabled()
 {
 	char buf[2];
Signature · 1 line
2.9.5
Applied
#8 lore raw
In reply to Daniel Borkmann
Quoted 9 lines · Daniel Borkmann

The series contains two fixes in BPF core and test cases. For details please see individual patches. Thanks!

Daniel Borkmann (4):
bpf: fix partial copy of map_ptr when dst is scalar
bpf: don't set id on after map lookup with ptr_to_map_val return
bpf: add various test cases to test_verifier
bpf: test make sure to run unpriv test cases in test_verifier

Quoted 4 lines
 include/linux/bpf_verifier.h                |   3 +
 kernel/bpf/verifier.c                       |  21 +-
 tools/testing/selftests/bpf/test_verifier.c | 321 +++++++++++++++++++++++++---
 3 files changed, 305 insertions(+), 40 deletions(-)

Applied to bpf tree, Thanks

... and we achieved very nice milestone... crossed 1000 tests in test_verifier :)

Summary: 1012 PASSED, 0 SKIPPED, 0 FAILED