From 288b3de55aace830f13280985ec9e6bcbff33b1b Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Mon, 20 Nov 2017 15:21:54 -0800 Subject: bpf: offload: move offload device validation out to the drivers With TC shared block changes we can't depend on correct netdev pointer being available in cls_bpf. Move the device validation to the driver. Core will only make sure that offloaded programs are always attached in the driver (or in HW by the driver). We trust that drivers which implement offload callbacks will perform necessary checks. Moving the checks to the driver is generally a useful thing, in practice the check should be against a switchdev instance, not a netdev, given that most ASICs will probably allow using the same program on many ports. Signed-off-by: Jakub Kicinski Reviewed-by: Quentin Monnet Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann Acked-by: Jiri Pirko Signed-off-by: Daniel Borkmann --- net/core/dev.c | 7 ++----- net/sched/cls_bpf.c | 8 +++----- 2 files changed, 5 insertions(+), 10 deletions(-) (limited to 'net') diff --git a/net/core/dev.c b/net/core/dev.c index 8ee29f4f5fa9..09525a27319c 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -7139,11 +7139,8 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, __dev_xdp_attached(dev, bpf_op, NULL)) return -EBUSY; - if (bpf_op == ops->ndo_bpf) - prog = bpf_prog_get_type_dev(fd, BPF_PROG_TYPE_XDP, - dev); - else - prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_XDP); + prog = bpf_prog_get_type_dev(fd, BPF_PROG_TYPE_XDP, + bpf_op == ops->ndo_bpf); if (IS_ERR(prog)) return PTR_ERR(prog); } diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c index fb680dafac5a..a9f3e317055c 100644 --- a/net/sched/cls_bpf.c +++ b/net/sched/cls_bpf.c @@ -382,15 +382,13 @@ static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog, { struct bpf_prog *fp; char *name = NULL; + bool skip_sw; u32 bpf_fd; bpf_fd = nla_get_u32(tb[TCA_BPF_FD]); + skip_sw = gen_flags & TCA_CLS_FLAGS_SKIP_SW; - if (gen_flags & TCA_CLS_FLAGS_SKIP_SW) - fp = bpf_prog_get_type_dev(bpf_fd, BPF_PROG_TYPE_SCHED_CLS, - qdisc_dev(tp->q)); - else - fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_CLS); + fp = bpf_prog_get_type_dev(bpf_fd, BPF_PROG_TYPE_SCHED_CLS, skip_sw); if (IS_ERR(fp)) return PTR_ERR(fp); -- cgit v1.2.3 From 441a33031fe5a3e828fbc17a4f9a5bab9143243c Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Mon, 20 Nov 2017 15:21:55 -0800 Subject: net: xdp: don't allow device-bound programs in driver mode Currently device-bound programs are not able to run on the host to save resources (host JIT is not invoked). Don't allow XDP programs to be attached without the HW_MODE flag. In theory if program is already translated for device offload the driver should choose to offload it instead of loading it in the driver. However, offloading translated program may still fail resulting in device-bound program being run on the host. Prevent this by refusing to attach device bound programs if XDP_FLAGS_HW_MODE is not set. Signed-off-by: Jakub Kicinski Reviewed-by: Quentin Monnet Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: Daniel Borkmann --- net/core/dev.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'net') diff --git a/net/core/dev.c b/net/core/dev.c index 09525a27319c..5e2ba133fba7 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -7143,6 +7143,13 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, bpf_op == ops->ndo_bpf); if (IS_ERR(prog)) return PTR_ERR(prog); + + if (!(flags & XDP_FLAGS_HW_MODE) && + bpf_prog_is_dev_bound(prog->aux)) { + NL_SET_ERR_MSG(extack, "using device-bound program without HW_MODE flag is not supported"); + bpf_prog_put(prog); + return -EINVAL; + } } err = dev_xdp_install(dev, bpf_op, extack, flags, prog); -- cgit v1.2.3 From db1ac4964fa172803a0fea83033cd35d380a8a77 Mon Sep 17 00:00:00 2001 From: Gianluca Borello Date: Wed, 22 Nov 2017 18:32:53 +0000 Subject: bpf: introduce ARG_PTR_TO_MEM_OR_NULL With the current ARG_PTR_TO_MEM/ARG_PTR_TO_UNINIT_MEM semantics, an helper argument can be NULL when the next argument type is ARG_CONST_SIZE_OR_ZERO and the verifier can prove the value of this next argument is 0. However, most helpers are just interested in handling , so forcing them to deal with makes the implementation of those helpers more complicated for no apparent benefits, requiring them to explicitly handle those corner cases with checks that bpf programs could start relying upon, preventing the possibility of removing them later. Solve this by making ARG_PTR_TO_MEM/ARG_PTR_TO_UNINIT_MEM never accept NULL even when ARG_CONST_SIZE_OR_ZERO is set, and introduce a new argument type ARG_PTR_TO_MEM_OR_NULL to explicitly deal with the NULL case. Currently, the only helper that needs this is bpf_csum_diff_proto(), so change arg1 and arg3 to this new type as well. Also add a new battery of tests that explicitly test the !ARG_PTR_TO_MEM_OR_NULL combination: all the current ones testing the various variations are focused on bpf_csum_diff, so cover also other helpers. Signed-off-by: Gianluca Borello Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: Daniel Borkmann --- include/linux/bpf.h | 1 + kernel/bpf/verifier.c | 4 +- net/core/filter.c | 4 +- tools/testing/selftests/bpf/test_verifier.c | 113 ++++++++++++++++++++++++++-- 4 files changed, 112 insertions(+), 10 deletions(-) (limited to 'net') diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 76c577281d78..e55e4255a210 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -78,6 +78,7 @@ enum bpf_arg_type { * functions that access data on eBPF program stack */ ARG_PTR_TO_MEM, /* pointer to valid memory (stack, packet, map value) */ + ARG_PTR_TO_MEM_OR_NULL, /* pointer to valid memory or NULL */ ARG_PTR_TO_UNINIT_MEM, /* pointer to memory does not need to be initialized, * helper function must fill all bytes or clear * them in error case. diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index dd54d20ace2f..308b0638ec5d 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1384,13 +1384,15 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, if (type != expected_type) goto err_type; } else if (arg_type == ARG_PTR_TO_MEM || + arg_type == ARG_PTR_TO_MEM_OR_NULL || arg_type == ARG_PTR_TO_UNINIT_MEM) { expected_type = PTR_TO_STACK; /* One exception here. In case function allows for NULL to be * passed in as argument, it's a SCALAR_VALUE type. Final test * happens during stack boundary checking. */ - if (register_is_null(*reg)) + if (register_is_null(*reg) && + arg_type == ARG_PTR_TO_MEM_OR_NULL) /* final test in check_stack_boundary() */; else if (!type_is_pkt_pointer(type) && type != PTR_TO_MAP_VALUE && diff --git a/net/core/filter.c b/net/core/filter.c index 1afa17935954..6a85e67fafce 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1646,9 +1646,9 @@ static const struct bpf_func_proto bpf_csum_diff_proto = { .gpl_only = false, .pkt_access = true, .ret_type = RET_INTEGER, - .arg1_type = ARG_PTR_TO_MEM, + .arg1_type = ARG_PTR_TO_MEM_OR_NULL, .arg2_type = ARG_CONST_SIZE_OR_ZERO, - .arg3_type = ARG_PTR_TO_MEM, + .arg3_type = ARG_PTR_TO_MEM_OR_NULL, .arg4_type = ARG_CONST_SIZE_OR_ZERO, .arg5_type = ARG_ANYTHING, }; diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 2a5267bef160..3c64f30cf63c 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -5631,7 +5631,7 @@ static struct bpf_test tests[] = { .prog_type = BPF_PROG_TYPE_TRACEPOINT, }, { - "helper access to variable memory: size = 0 allowed on NULL", + "helper access to variable memory: size = 0 allowed on NULL (ARG_PTR_TO_MEM_OR_NULL)", .insns = { BPF_MOV64_IMM(BPF_REG_1, 0), BPF_MOV64_IMM(BPF_REG_2, 0), @@ -5645,7 +5645,7 @@ static struct bpf_test tests[] = { .prog_type = BPF_PROG_TYPE_SCHED_CLS, }, { - "helper access to variable memory: size > 0 not allowed on NULL", + "helper access to variable memory: size > 0 not allowed on NULL (ARG_PTR_TO_MEM_OR_NULL)", .insns = { BPF_MOV64_IMM(BPF_REG_1, 0), BPF_MOV64_IMM(BPF_REG_2, 0), @@ -5663,7 +5663,7 @@ static struct bpf_test tests[] = { .prog_type = BPF_PROG_TYPE_SCHED_CLS, }, { - "helper access to variable memory: size = 0 allowed on != NULL stack pointer", + "helper access to variable memory: size = 0 allowed on != NULL stack pointer (ARG_PTR_TO_MEM_OR_NULL)", .insns = { BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8), @@ -5680,7 +5680,7 @@ static struct bpf_test tests[] = { .prog_type = BPF_PROG_TYPE_SCHED_CLS, }, { - "helper access to variable memory: size = 0 allowed on != NULL map pointer", + "helper access to variable memory: size = 0 allowed on != NULL map pointer (ARG_PTR_TO_MEM_OR_NULL)", .insns = { BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), @@ -5702,7 +5702,7 @@ static struct bpf_test tests[] = { .prog_type = BPF_PROG_TYPE_SCHED_CLS, }, { - "helper access to variable memory: size possible = 0 allowed on != NULL stack pointer", + "helper access to variable memory: size possible = 0 allowed on != NULL stack pointer (ARG_PTR_TO_MEM_OR_NULL)", .insns = { BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), @@ -5727,7 +5727,7 @@ static struct bpf_test tests[] = { .prog_type = BPF_PROG_TYPE_SCHED_CLS, }, { - "helper access to variable memory: size possible = 0 allowed on != NULL map pointer", + "helper access to variable memory: size possible = 0 allowed on != NULL map pointer (ARG_PTR_TO_MEM_OR_NULL)", .insns = { BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), @@ -5750,7 +5750,7 @@ static struct bpf_test tests[] = { .prog_type = BPF_PROG_TYPE_SCHED_CLS, }, { - "helper access to variable memory: size possible = 0 allowed on != NULL packet pointer", + "helper access to variable memory: size possible = 0 allowed on != NULL packet pointer (ARG_PTR_TO_MEM_OR_NULL)", .insns = { BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, data)), @@ -5771,6 +5771,105 @@ static struct bpf_test tests[] = { .result = ACCEPT, .prog_type = BPF_PROG_TYPE_SCHED_CLS, }, + { + "helper access to variable memory: size = 0 not allowed on NULL (!ARG_PTR_TO_MEM_OR_NULL)", + .insns = { + BPF_MOV64_IMM(BPF_REG_1, 0), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_EMIT_CALL(BPF_FUNC_probe_read), + BPF_EXIT_INSN(), + }, + .errstr = "R1 type=inv expected=fp", + .result = REJECT, + .prog_type = BPF_PROG_TYPE_TRACEPOINT, + }, + { + "helper access to variable memory: size > 0 not allowed on NULL (!ARG_PTR_TO_MEM_OR_NULL)", + .insns = { + BPF_MOV64_IMM(BPF_REG_1, 0), + BPF_MOV64_IMM(BPF_REG_2, 1), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_EMIT_CALL(BPF_FUNC_probe_read), + BPF_EXIT_INSN(), + }, + .errstr = "R1 type=inv expected=fp", + .result = REJECT, + .prog_type = BPF_PROG_TYPE_TRACEPOINT, + }, + { + "helper access to variable memory: size = 0 allowed on != NULL stack pointer (!ARG_PTR_TO_MEM_OR_NULL)", + .insns = { + BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_EMIT_CALL(BPF_FUNC_probe_read), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_TRACEPOINT, + }, + { + "helper access to variable memory: size = 0 allowed on != NULL map pointer (!ARG_PTR_TO_MEM_OR_NULL)", + .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_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_EMIT_CALL(BPF_FUNC_probe_read), + BPF_EXIT_INSN(), + }, + .fixup_map1 = { 3 }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_TRACEPOINT, + }, + { + "helper access to variable memory: size possible = 0 allowed on != NULL stack pointer (!ARG_PTR_TO_MEM_OR_NULL)", + .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_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6), + BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0), + BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 8, 4), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_EMIT_CALL(BPF_FUNC_probe_read), + BPF_EXIT_INSN(), + }, + .fixup_map1 = { 3 }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_TRACEPOINT, + }, + { + "helper access to variable memory: size possible = 0 allowed on != NULL map pointer (!ARG_PTR_TO_MEM_OR_NULL)", + .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_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 5), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0), + BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 8, 2), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_EMIT_CALL(BPF_FUNC_probe_read), + BPF_EXIT_INSN(), + }, + .fixup_map1 = { 3 }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_TRACEPOINT, + }, { "helper access to variable memory: 8 bytes leak", .insns = { -- cgit v1.2.3