* [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr @ 2019-06-28 23:10 Stanislav Fomichev 2019-06-28 23:10 ` [PATCH bpf-next 2/2] selftests/bpf: add verifier tests for wide stores Stanislav Fomichev 2019-06-30 5:52 ` [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr Yonghong Song 0 siblings, 2 replies; 11+ messages in thread From: Stanislav Fomichev @ 2019-06-28 23:10 UTC (permalink / raw) To: netdev, bpf Cc: davem, ast, daniel, Stanislav Fomichev, Andrii Nakryiko, Yonghong Song, kernel test robot Since commit cd17d7770578 ("bpf/tools: sync bpf.h") clang decided that it can do a single u64 store into user_ip6[2] instead of two separate u32 ones: # 17: (18) r2 = 0x100000000000000 # ; ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2); # 19: (7b) *(u64 *)(r1 +16) = r2 # invalid bpf_context access off=16 size=8 From the compiler point of view it does look like a correct thing to do, so let's support it on the kernel side. Credit to Andrii Nakryiko for a proper implementation of bpf_ctx_wide_store_ok. Cc: Andrii Nakryiko <andriin@fb.com> Cc: Yonghong Song <yhs@fb.com> Fixes: cd17d7770578 ("bpf/tools: sync bpf.h") Reported-by: kernel test robot <rong.a.chen@intel.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> --- include/linux/filter.h | 6 ++++++ net/core/filter.c | 22 ++++++++++++++-------- 2 files changed, 20 insertions(+), 8 deletions(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index 340f7d648974..3901007e36f1 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -746,6 +746,12 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default) return size <= size_default && (size & (size - 1)) == 0; } +#define bpf_ctx_wide_store_ok(off, size, type, field) \ + (size == sizeof(__u64) && \ + off >= offsetof(type, field) && \ + off + sizeof(__u64) <= offsetofend(type, field) && \ + off % sizeof(__u64) == 0) + #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) static inline void bpf_prog_lock_ro(struct bpf_prog *fp) diff --git a/net/core/filter.c b/net/core/filter.c index dc8534be12fc..5d33f2146dab 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -6849,6 +6849,16 @@ static bool sock_addr_is_valid_access(int off, int size, if (!bpf_ctx_narrow_access_ok(off, size, size_default)) return false; } else { + if (bpf_ctx_wide_store_ok(off, size, + struct bpf_sock_addr, + user_ip6)) + return true; + + if (bpf_ctx_wide_store_ok(off, size, + struct bpf_sock_addr, + msg_src_ip6)) + return true; + if (size != size_default) return false; } @@ -7689,9 +7699,6 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, /* SOCK_ADDR_STORE_NESTED_FIELD_OFF() has semantic similar to * SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF() but for store operation. * - * It doesn't support SIZE argument though since narrow stores are not - * supported for now. - * * In addition it uses Temporary Field TF (member of struct S) as the 3rd * "register" since two registers available in convert_ctx_access are not * enough: we can't override neither SRC, since it contains value to store, nor @@ -7699,7 +7706,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, * instructions. But we need a temporary place to save pointer to nested * structure whose field we want to store to. */ -#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, TF) \ +#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, OFF, TF) \ do { \ int tmp_reg = BPF_REG_9; \ if (si->src_reg == tmp_reg || si->dst_reg == tmp_reg) \ @@ -7710,8 +7717,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, offsetof(S, TF)); \ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(S, F), tmp_reg, \ si->dst_reg, offsetof(S, F)); \ - *insn++ = BPF_STX_MEM( \ - BPF_FIELD_SIZEOF(NS, NF), tmp_reg, si->src_reg, \ + *insn++ = BPF_STX_MEM(SIZE, tmp_reg, si->src_reg, \ bpf_target_off(NS, NF, FIELD_SIZEOF(NS, NF), \ target_size) \ + OFF); \ @@ -7723,8 +7729,8 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, TF) \ do { \ if (type == BPF_WRITE) { \ - SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, \ - TF); \ + SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, \ + OFF, TF); \ } else { \ SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF( \ S, NS, F, NF, SIZE, OFF); \ -- 2.22.0.410.gd8fdbe21b5-goog ^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH bpf-next 2/2] selftests/bpf: add verifier tests for wide stores 2019-06-28 23:10 [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr Stanislav Fomichev @ 2019-06-28 23:10 ` Stanislav Fomichev 2019-06-30 6:01 ` Yonghong Song 2019-06-30 5:52 ` [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr Yonghong Song 1 sibling, 1 reply; 11+ messages in thread From: Stanislav Fomichev @ 2019-06-28 23:10 UTC (permalink / raw) To: netdev, bpf Cc: davem, ast, daniel, Stanislav Fomichev, Andrii Nakryiko, Yonghong Song Make sure that wide stores are allowed at proper (aligned) addresses. Note that user_ip6 is naturally aligned on 8-byte boundary, so correct addresses are user_ip6[0] and user_ip6[2]. msg_src_ip6 is, however, aligned on a 4-byte bondary, so only msg_src_ip6[1] can be wide-stored. Cc: Andrii Nakryiko <andriin@fb.com> Cc: Yonghong Song <yhs@fb.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> --- tools/testing/selftests/bpf/test_verifier.c | 17 ++++++-- .../selftests/bpf/verifier/wide_store.c | 40 +++++++++++++++++++ 2 files changed, 54 insertions(+), 3 deletions(-) create mode 100644 tools/testing/selftests/bpf/verifier/wide_store.c diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index c5514daf8865..b0773291012a 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -105,6 +105,7 @@ struct bpf_test { __u64 data64[TEST_DATA_LEN / 8]; }; } retvals[MAX_TEST_RUNS]; + enum bpf_attach_type expected_attach_type; }; /* Note we want this to be 64 bit aligned so that the end of our array is @@ -850,6 +851,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv, int fd_prog, expected_ret, alignment_prevented_execution; int prog_len, prog_type = test->prog_type; struct bpf_insn *prog = test->insns; + struct bpf_load_program_attr attr; int run_errs, run_successes; int map_fds[MAX_NR_MAPS]; const char *expected_err; @@ -881,8 +883,17 @@ static void do_test_single(struct bpf_test *test, bool unpriv, pflags |= BPF_F_STRICT_ALIGNMENT; if (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS) pflags |= BPF_F_ANY_ALIGNMENT; - fd_prog = bpf_verify_program(prog_type, prog, prog_len, pflags, - "GPL", 0, bpf_vlog, sizeof(bpf_vlog), 4); + + memset(&attr, 0, sizeof(attr)); + attr.prog_type = prog_type; + attr.expected_attach_type = test->expected_attach_type; + attr.insns = prog; + attr.insns_cnt = prog_len; + attr.license = "GPL"; + attr.log_level = 4; + attr.prog_flags = pflags; + + fd_prog = bpf_load_program_xattr(&attr, bpf_vlog, sizeof(bpf_vlog)); if (fd_prog < 0 && !bpf_probe_prog_type(prog_type, 0)) { printf("SKIP (unsupported program type %d)\n", prog_type); skips++; @@ -912,7 +923,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv, printf("FAIL\nUnexpected success to load!\n"); goto fail_log; } - if (!strstr(bpf_vlog, expected_err)) { + if (!expected_err || !strstr(bpf_vlog, expected_err)) { printf("FAIL\nUnexpected error message!\n\tEXP: %s\n\tRES: %s\n", expected_err, bpf_vlog); goto fail_log; diff --git a/tools/testing/selftests/bpf/verifier/wide_store.c b/tools/testing/selftests/bpf/verifier/wide_store.c new file mode 100644 index 000000000000..c6385f45b114 --- /dev/null +++ b/tools/testing/selftests/bpf/verifier/wide_store.c @@ -0,0 +1,40 @@ +#define BPF_SOCK_ADDR(field, off, res, err) \ +{ \ + "wide store to bpf_sock_addr." #field "[" #off "]", \ + .insns = { \ + BPF_MOV64_IMM(BPF_REG_0, 1), \ + BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, \ + offsetof(struct bpf_sock_addr, field[off])), \ + BPF_EXIT_INSN(), \ + }, \ + .result = res, \ + .prog_type = BPF_PROG_TYPE_CGROUP_SOCK_ADDR, \ + .expected_attach_type = BPF_CGROUP_UDP6_SENDMSG, \ + .errstr = err, \ +} + +/* user_ip6[0] is u64 aligned */ +BPF_SOCK_ADDR(user_ip6, 0, ACCEPT, + NULL), +BPF_SOCK_ADDR(user_ip6, 1, REJECT, + "invalid bpf_context access off=12 size=8"), +BPF_SOCK_ADDR(user_ip6, 2, ACCEPT, + NULL), +BPF_SOCK_ADDR(user_ip6, 3, REJECT, + "invalid bpf_context access off=20 size=8"), +BPF_SOCK_ADDR(user_ip6, 4, REJECT, + "invalid bpf_context access off=24 size=8"), + +/* msg_src_ip6[0] is _not_ u64 aligned */ +BPF_SOCK_ADDR(msg_src_ip6, 0, REJECT, + "invalid bpf_context access off=44 size=8"), +BPF_SOCK_ADDR(msg_src_ip6, 1, ACCEPT, + NULL), +BPF_SOCK_ADDR(msg_src_ip6, 2, REJECT, + "invalid bpf_context access off=52 size=8"), +BPF_SOCK_ADDR(msg_src_ip6, 3, REJECT, + "invalid bpf_context access off=56 size=8"), +BPF_SOCK_ADDR(msg_src_ip6, 4, REJECT, + "invalid bpf_context access off=60 size=8"), + +#undef BPF_SOCK_ADDR -- 2.22.0.410.gd8fdbe21b5-goog ^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH bpf-next 2/2] selftests/bpf: add verifier tests for wide stores 2019-06-28 23:10 ` [PATCH bpf-next 2/2] selftests/bpf: add verifier tests for wide stores Stanislav Fomichev @ 2019-06-30 6:01 ` Yonghong Song 2019-07-01 15:44 ` Andrii Nakryiko 2019-07-01 16:00 ` Stanislav Fomichev 0 siblings, 2 replies; 11+ messages in thread From: Yonghong Song @ 2019-06-30 6:01 UTC (permalink / raw) To: Stanislav Fomichev, netdev, bpf; +Cc: davem, ast, daniel, Andrii Nakryiko On 6/28/19 4:10 PM, Stanislav Fomichev wrote: > Make sure that wide stores are allowed at proper (aligned) addresses. > Note that user_ip6 is naturally aligned on 8-byte boundary, so > correct addresses are user_ip6[0] and user_ip6[2]. msg_src_ip6 is, > however, aligned on a 4-byte bondary, so only msg_src_ip6[1] > can be wide-stored. > > Cc: Andrii Nakryiko <andriin@fb.com> > Cc: Yonghong Song <yhs@fb.com> > Signed-off-by: Stanislav Fomichev <sdf@google.com> > --- > tools/testing/selftests/bpf/test_verifier.c | 17 ++++++-- > .../selftests/bpf/verifier/wide_store.c | 40 +++++++++++++++++++ > 2 files changed, 54 insertions(+), 3 deletions(-) > create mode 100644 tools/testing/selftests/bpf/verifier/wide_store.c > > diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c > index c5514daf8865..b0773291012a 100644 > --- a/tools/testing/selftests/bpf/test_verifier.c > +++ b/tools/testing/selftests/bpf/test_verifier.c > @@ -105,6 +105,7 @@ struct bpf_test { > __u64 data64[TEST_DATA_LEN / 8]; > }; > } retvals[MAX_TEST_RUNS]; > + enum bpf_attach_type expected_attach_type; > }; > > /* Note we want this to be 64 bit aligned so that the end of our array is > @@ -850,6 +851,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv, > int fd_prog, expected_ret, alignment_prevented_execution; > int prog_len, prog_type = test->prog_type; > struct bpf_insn *prog = test->insns; > + struct bpf_load_program_attr attr; > int run_errs, run_successes; > int map_fds[MAX_NR_MAPS]; > const char *expected_err; > @@ -881,8 +883,17 @@ static void do_test_single(struct bpf_test *test, bool unpriv, > pflags |= BPF_F_STRICT_ALIGNMENT; > if (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS) > pflags |= BPF_F_ANY_ALIGNMENT; > - fd_prog = bpf_verify_program(prog_type, prog, prog_len, pflags, > - "GPL", 0, bpf_vlog, sizeof(bpf_vlog), 4); > + > + memset(&attr, 0, sizeof(attr)); > + attr.prog_type = prog_type; > + attr.expected_attach_type = test->expected_attach_type; > + attr.insns = prog; > + attr.insns_cnt = prog_len; > + attr.license = "GPL"; > + attr.log_level = 4; > + attr.prog_flags = pflags; > + > + fd_prog = bpf_load_program_xattr(&attr, bpf_vlog, sizeof(bpf_vlog)); > if (fd_prog < 0 && !bpf_probe_prog_type(prog_type, 0)) { > printf("SKIP (unsupported program type %d)\n", prog_type); > skips++; > @@ -912,7 +923,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv, > printf("FAIL\nUnexpected success to load!\n"); > goto fail_log; > } > - if (!strstr(bpf_vlog, expected_err)) { > + if (!expected_err || !strstr(bpf_vlog, expected_err)) { > printf("FAIL\nUnexpected error message!\n\tEXP: %s\n\tRES: %s\n", > expected_err, bpf_vlog); > goto fail_log; > diff --git a/tools/testing/selftests/bpf/verifier/wide_store.c b/tools/testing/selftests/bpf/verifier/wide_store.c > new file mode 100644 > index 000000000000..c6385f45b114 > --- /dev/null > +++ b/tools/testing/selftests/bpf/verifier/wide_store.c > @@ -0,0 +1,40 @@ > +#define BPF_SOCK_ADDR(field, off, res, err) \ > +{ \ > + "wide store to bpf_sock_addr." #field "[" #off "]", \ > + .insns = { \ > + BPF_MOV64_IMM(BPF_REG_0, 1), \ > + BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, \ > + offsetof(struct bpf_sock_addr, field[off])), \ > + BPF_EXIT_INSN(), \ > + }, \ > + .result = res, \ > + .prog_type = BPF_PROG_TYPE_CGROUP_SOCK_ADDR, \ > + .expected_attach_type = BPF_CGROUP_UDP6_SENDMSG, \ > + .errstr = err, \ > +} > + > +/* user_ip6[0] is u64 aligned */ > +BPF_SOCK_ADDR(user_ip6, 0, ACCEPT, > + NULL), > +BPF_SOCK_ADDR(user_ip6, 1, REJECT, > + "invalid bpf_context access off=12 size=8"), > +BPF_SOCK_ADDR(user_ip6, 2, ACCEPT, > + NULL), > +BPF_SOCK_ADDR(user_ip6, 3, REJECT, > + "invalid bpf_context access off=20 size=8"), > +BPF_SOCK_ADDR(user_ip6, 4, REJECT, > + "invalid bpf_context access off=24 size=8"), With offset 4, we have #968/p wide store to bpf_sock_addr.user_ip6[4] OK This test case can be removed. user code typically won't write bpf_sock_addr.user_ip6[4], and compiler typically will give a warning since it is out of array bound. Any particular reason you want to include this one? > + > +/* msg_src_ip6[0] is _not_ u64 aligned */ > +BPF_SOCK_ADDR(msg_src_ip6, 0, REJECT, > + "invalid bpf_context access off=44 size=8"), > +BPF_SOCK_ADDR(msg_src_ip6, 1, ACCEPT, > + NULL), > +BPF_SOCK_ADDR(msg_src_ip6, 2, REJECT, > + "invalid bpf_context access off=52 size=8"), > +BPF_SOCK_ADDR(msg_src_ip6, 3, REJECT, > + "invalid bpf_context access off=56 size=8"), > +BPF_SOCK_ADDR(msg_src_ip6, 4, REJECT, > + "invalid bpf_context access off=60 size=8"), The same as above, offset=4 case can be removed? > + > +#undef BPF_SOCK_ADDR > ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH bpf-next 2/2] selftests/bpf: add verifier tests for wide stores 2019-06-30 6:01 ` Yonghong Song @ 2019-07-01 15:44 ` Andrii Nakryiko 2019-07-01 16:00 ` Stanislav Fomichev 1 sibling, 0 replies; 11+ messages in thread From: Andrii Nakryiko @ 2019-07-01 15:44 UTC (permalink / raw) To: Yonghong Song Cc: Stanislav Fomichev, netdev, bpf, davem, ast, daniel, Andrii Nakryiko On Sat, Jun 29, 2019 at 11:02 PM Yonghong Song <yhs@fb.com> wrote: > > > > On 6/28/19 4:10 PM, Stanislav Fomichev wrote: > > Make sure that wide stores are allowed at proper (aligned) addresses. > > Note that user_ip6 is naturally aligned on 8-byte boundary, so > > correct addresses are user_ip6[0] and user_ip6[2]. msg_src_ip6 is, > > however, aligned on a 4-byte bondary, so only msg_src_ip6[1] > > can be wide-stored. > > > > Cc: Andrii Nakryiko <andriin@fb.com> > > Cc: Yonghong Song <yhs@fb.com> > > Signed-off-by: Stanislav Fomichev <sdf@google.com> > > --- > > tools/testing/selftests/bpf/test_verifier.c | 17 ++++++-- > > .../selftests/bpf/verifier/wide_store.c | 40 +++++++++++++++++++ > > 2 files changed, 54 insertions(+), 3 deletions(-) > > create mode 100644 tools/testing/selftests/bpf/verifier/wide_store.c > > > > diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c > > index c5514daf8865..b0773291012a 100644 > > --- a/tools/testing/selftests/bpf/test_verifier.c > > +++ b/tools/testing/selftests/bpf/test_verifier.c > > @@ -105,6 +105,7 @@ struct bpf_test { > > __u64 data64[TEST_DATA_LEN / 8]; > > }; > > } retvals[MAX_TEST_RUNS]; > > + enum bpf_attach_type expected_attach_type; > > }; > > > > /* Note we want this to be 64 bit aligned so that the end of our array is > > @@ -850,6 +851,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv, > > int fd_prog, expected_ret, alignment_prevented_execution; > > int prog_len, prog_type = test->prog_type; > > struct bpf_insn *prog = test->insns; > > + struct bpf_load_program_attr attr; > > int run_errs, run_successes; > > int map_fds[MAX_NR_MAPS]; > > const char *expected_err; > > @@ -881,8 +883,17 @@ static void do_test_single(struct bpf_test *test, bool unpriv, > > pflags |= BPF_F_STRICT_ALIGNMENT; > > if (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS) > > pflags |= BPF_F_ANY_ALIGNMENT; > > - fd_prog = bpf_verify_program(prog_type, prog, prog_len, pflags, > > - "GPL", 0, bpf_vlog, sizeof(bpf_vlog), 4); > > + > > + memset(&attr, 0, sizeof(attr)); > > + attr.prog_type = prog_type; > > + attr.expected_attach_type = test->expected_attach_type; > > + attr.insns = prog; > > + attr.insns_cnt = prog_len; > > + attr.license = "GPL"; > > + attr.log_level = 4; > > + attr.prog_flags = pflags; > > + > > + fd_prog = bpf_load_program_xattr(&attr, bpf_vlog, sizeof(bpf_vlog)); > > if (fd_prog < 0 && !bpf_probe_prog_type(prog_type, 0)) { > > printf("SKIP (unsupported program type %d)\n", prog_type); > > skips++; > > @@ -912,7 +923,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv, > > printf("FAIL\nUnexpected success to load!\n"); > > goto fail_log; > > } > > - if (!strstr(bpf_vlog, expected_err)) { > > + if (!expected_err || !strstr(bpf_vlog, expected_err)) { > > printf("FAIL\nUnexpected error message!\n\tEXP: %s\n\tRES: %s\n", > > expected_err, bpf_vlog); > > goto fail_log; > > diff --git a/tools/testing/selftests/bpf/verifier/wide_store.c b/tools/testing/selftests/bpf/verifier/wide_store.c > > new file mode 100644 > > index 000000000000..c6385f45b114 > > --- /dev/null > > +++ b/tools/testing/selftests/bpf/verifier/wide_store.c > > @@ -0,0 +1,40 @@ > > +#define BPF_SOCK_ADDR(field, off, res, err) \ > > +{ \ > > + "wide store to bpf_sock_addr." #field "[" #off "]", \ > > + .insns = { \ > > + BPF_MOV64_IMM(BPF_REG_0, 1), \ > > + BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, \ > > + offsetof(struct bpf_sock_addr, field[off])), \ > > + BPF_EXIT_INSN(), \ > > + }, \ > > + .result = res, \ > > + .prog_type = BPF_PROG_TYPE_CGROUP_SOCK_ADDR, \ > > + .expected_attach_type = BPF_CGROUP_UDP6_SENDMSG, \ > > + .errstr = err, \ > > +} > > + > > +/* user_ip6[0] is u64 aligned */ > > +BPF_SOCK_ADDR(user_ip6, 0, ACCEPT, > > + NULL), > > +BPF_SOCK_ADDR(user_ip6, 1, REJECT, > > + "invalid bpf_context access off=12 size=8"), > > +BPF_SOCK_ADDR(user_ip6, 2, ACCEPT, > > + NULL), > > +BPF_SOCK_ADDR(user_ip6, 3, REJECT, > > + "invalid bpf_context access off=20 size=8"), > > +BPF_SOCK_ADDR(user_ip6, 4, REJECT, > > + "invalid bpf_context access off=24 size=8"), > > With offset 4, we have > #968/p wide store to bpf_sock_addr.user_ip6[4] OK > > This test case can be removed. user code typically > won't write bpf_sock_addr.user_ip6[4], and compiler > typically will give a warning since it is out of > array bound. Any particular reason you want to > include this one? I agree, user_ip6[4] is essentially 8-byte write to user_port field. > > > > + > > +/* msg_src_ip6[0] is _not_ u64 aligned */ > > +BPF_SOCK_ADDR(msg_src_ip6, 0, REJECT, > > + "invalid bpf_context access off=44 size=8"), > > +BPF_SOCK_ADDR(msg_src_ip6, 1, ACCEPT, > > + NULL), > > +BPF_SOCK_ADDR(msg_src_ip6, 2, REJECT, > > + "invalid bpf_context access off=52 size=8"), > > +BPF_SOCK_ADDR(msg_src_ip6, 3, REJECT, > > + "invalid bpf_context access off=56 size=8"), > > +BPF_SOCK_ADDR(msg_src_ip6, 4, REJECT, > > + "invalid bpf_context access off=60 size=8"), > > The same as above, offset=4 case can be removed? And this one is a write into a struct hole, which should be rejected even without wide-store check, right? > > > + > > +#undef BPF_SOCK_ADDR > > ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH bpf-next 2/2] selftests/bpf: add verifier tests for wide stores 2019-06-30 6:01 ` Yonghong Song 2019-07-01 15:44 ` Andrii Nakryiko @ 2019-07-01 16:00 ` Stanislav Fomichev 1 sibling, 0 replies; 11+ messages in thread From: Stanislav Fomichev @ 2019-07-01 16:00 UTC (permalink / raw) To: Yonghong Song Cc: Stanislav Fomichev, netdev, bpf, davem, ast, daniel, Andrii Nakryiko On 06/30, Yonghong Song wrote: > > > On 6/28/19 4:10 PM, Stanislav Fomichev wrote: > > Make sure that wide stores are allowed at proper (aligned) addresses. > > Note that user_ip6 is naturally aligned on 8-byte boundary, so > > correct addresses are user_ip6[0] and user_ip6[2]. msg_src_ip6 is, > > however, aligned on a 4-byte bondary, so only msg_src_ip6[1] > > can be wide-stored. > > > > Cc: Andrii Nakryiko <andriin@fb.com> > > Cc: Yonghong Song <yhs@fb.com> > > Signed-off-by: Stanislav Fomichev <sdf@google.com> > > --- > > tools/testing/selftests/bpf/test_verifier.c | 17 ++++++-- > > .../selftests/bpf/verifier/wide_store.c | 40 +++++++++++++++++++ > > 2 files changed, 54 insertions(+), 3 deletions(-) > > create mode 100644 tools/testing/selftests/bpf/verifier/wide_store.c > > > > diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c > > index c5514daf8865..b0773291012a 100644 > > --- a/tools/testing/selftests/bpf/test_verifier.c > > +++ b/tools/testing/selftests/bpf/test_verifier.c > > @@ -105,6 +105,7 @@ struct bpf_test { > > __u64 data64[TEST_DATA_LEN / 8]; > > }; > > } retvals[MAX_TEST_RUNS]; > > + enum bpf_attach_type expected_attach_type; > > }; > > > > /* Note we want this to be 64 bit aligned so that the end of our array is > > @@ -850,6 +851,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv, > > int fd_prog, expected_ret, alignment_prevented_execution; > > int prog_len, prog_type = test->prog_type; > > struct bpf_insn *prog = test->insns; > > + struct bpf_load_program_attr attr; > > int run_errs, run_successes; > > int map_fds[MAX_NR_MAPS]; > > const char *expected_err; > > @@ -881,8 +883,17 @@ static void do_test_single(struct bpf_test *test, bool unpriv, > > pflags |= BPF_F_STRICT_ALIGNMENT; > > if (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS) > > pflags |= BPF_F_ANY_ALIGNMENT; > > - fd_prog = bpf_verify_program(prog_type, prog, prog_len, pflags, > > - "GPL", 0, bpf_vlog, sizeof(bpf_vlog), 4); > > + > > + memset(&attr, 0, sizeof(attr)); > > + attr.prog_type = prog_type; > > + attr.expected_attach_type = test->expected_attach_type; > > + attr.insns = prog; > > + attr.insns_cnt = prog_len; > > + attr.license = "GPL"; > > + attr.log_level = 4; > > + attr.prog_flags = pflags; > > + > > + fd_prog = bpf_load_program_xattr(&attr, bpf_vlog, sizeof(bpf_vlog)); > > if (fd_prog < 0 && !bpf_probe_prog_type(prog_type, 0)) { > > printf("SKIP (unsupported program type %d)\n", prog_type); > > skips++; > > @@ -912,7 +923,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv, > > printf("FAIL\nUnexpected success to load!\n"); > > goto fail_log; > > } > > - if (!strstr(bpf_vlog, expected_err)) { > > + if (!expected_err || !strstr(bpf_vlog, expected_err)) { > > printf("FAIL\nUnexpected error message!\n\tEXP: %s\n\tRES: %s\n", > > expected_err, bpf_vlog); > > goto fail_log; > > diff --git a/tools/testing/selftests/bpf/verifier/wide_store.c b/tools/testing/selftests/bpf/verifier/wide_store.c > > new file mode 100644 > > index 000000000000..c6385f45b114 > > --- /dev/null > > +++ b/tools/testing/selftests/bpf/verifier/wide_store.c > > @@ -0,0 +1,40 @@ > > +#define BPF_SOCK_ADDR(field, off, res, err) \ > > +{ \ > > + "wide store to bpf_sock_addr." #field "[" #off "]", \ > > + .insns = { \ > > + BPF_MOV64_IMM(BPF_REG_0, 1), \ > > + BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, \ > > + offsetof(struct bpf_sock_addr, field[off])), \ > > + BPF_EXIT_INSN(), \ > > + }, \ > > + .result = res, \ > > + .prog_type = BPF_PROG_TYPE_CGROUP_SOCK_ADDR, \ > > + .expected_attach_type = BPF_CGROUP_UDP6_SENDMSG, \ > > + .errstr = err, \ > > +} > > + > > +/* user_ip6[0] is u64 aligned */ > > +BPF_SOCK_ADDR(user_ip6, 0, ACCEPT, > > + NULL), > > +BPF_SOCK_ADDR(user_ip6, 1, REJECT, > > + "invalid bpf_context access off=12 size=8"), > > +BPF_SOCK_ADDR(user_ip6, 2, ACCEPT, > > + NULL), > > +BPF_SOCK_ADDR(user_ip6, 3, REJECT, > > + "invalid bpf_context access off=20 size=8"), > > +BPF_SOCK_ADDR(user_ip6, 4, REJECT, > > + "invalid bpf_context access off=24 size=8"), > > With offset 4, we have > #968/p wide store to bpf_sock_addr.user_ip6[4] OK > > This test case can be removed. user code typically > won't write bpf_sock_addr.user_ip6[4], and compiler > typically will give a warning since it is out of > array bound. Any particular reason you want to > include this one? Agreed on both, I'm being overly cautious here. They should be caught by the outer switch and be rejected because of other reasons. > > + > > +/* msg_src_ip6[0] is _not_ u64 aligned */ > > +BPF_SOCK_ADDR(msg_src_ip6, 0, REJECT, > > + "invalid bpf_context access off=44 size=8"), > > +BPF_SOCK_ADDR(msg_src_ip6, 1, ACCEPT, > > + NULL), > > +BPF_SOCK_ADDR(msg_src_ip6, 2, REJECT, > > + "invalid bpf_context access off=52 size=8"), > > +BPF_SOCK_ADDR(msg_src_ip6, 3, REJECT, > > + "invalid bpf_context access off=56 size=8"), > > +BPF_SOCK_ADDR(msg_src_ip6, 4, REJECT, > > + "invalid bpf_context access off=60 size=8"), > > The same as above, offset=4 case can be removed? > > > + > > +#undef BPF_SOCK_ADDR > > ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr 2019-06-28 23:10 [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr Stanislav Fomichev 2019-06-28 23:10 ` [PATCH bpf-next 2/2] selftests/bpf: add verifier tests for wide stores Stanislav Fomichev @ 2019-06-30 5:52 ` Yonghong Song 2019-07-01 15:36 ` Andrii Nakryiko 2019-07-01 16:01 ` Stanislav Fomichev 1 sibling, 2 replies; 11+ messages in thread From: Yonghong Song @ 2019-06-30 5:52 UTC (permalink / raw) To: Stanislav Fomichev, netdev, bpf Cc: davem, ast, daniel, Andrii Nakryiko, kernel test robot On 6/28/19 4:10 PM, Stanislav Fomichev wrote: > Since commit cd17d7770578 ("bpf/tools: sync bpf.h") clang decided > that it can do a single u64 store into user_ip6[2] instead of two > separate u32 ones: > > # 17: (18) r2 = 0x100000000000000 > # ; ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2); > # 19: (7b) *(u64 *)(r1 +16) = r2 > # invalid bpf_context access off=16 size=8 > > From the compiler point of view it does look like a correct thing > to do, so let's support it on the kernel side. > > Credit to Andrii Nakryiko for a proper implementation of > bpf_ctx_wide_store_ok. > > Cc: Andrii Nakryiko <andriin@fb.com> > Cc: Yonghong Song <yhs@fb.com> > Fixes: cd17d7770578 ("bpf/tools: sync bpf.h") > Reported-by: kernel test robot <rong.a.chen@intel.com> > Signed-off-by: Stanislav Fomichev <sdf@google.com> The change looks good to me with the following nits: 1. could you add a cover letter for the patch set? typically if the number of patches is more than one, it would be a good practice with a cover letter. See bpf_devel_QA.rst . 2. with this change, the comments in uapi bpf.h are not accurate any more. __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. * Stored in network byte order. */ __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. * Stored in network byte order. */ now for stores, aligned 8-byte write is permitted. could you update this as well? From the typical usage pattern, I did not see a need for 8-tye read of user_ip6 and msg_src_ip6 yet. So let us just deal with write for now. With the above two nits, Acked-by: Yonghong Song <yhs@fb.com> > --- > include/linux/filter.h | 6 ++++++ > net/core/filter.c | 22 ++++++++++++++-------- > 2 files changed, 20 insertions(+), 8 deletions(-) > > diff --git a/include/linux/filter.h b/include/linux/filter.h > index 340f7d648974..3901007e36f1 100644 > --- a/include/linux/filter.h > +++ b/include/linux/filter.h > @@ -746,6 +746,12 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default) > return size <= size_default && (size & (size - 1)) == 0; > } > > +#define bpf_ctx_wide_store_ok(off, size, type, field) \ > + (size == sizeof(__u64) && \ > + off >= offsetof(type, field) && \ > + off + sizeof(__u64) <= offsetofend(type, field) && \ > + off % sizeof(__u64) == 0) > + > #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) > > static inline void bpf_prog_lock_ro(struct bpf_prog *fp) > diff --git a/net/core/filter.c b/net/core/filter.c > index dc8534be12fc..5d33f2146dab 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -6849,6 +6849,16 @@ static bool sock_addr_is_valid_access(int off, int size, > if (!bpf_ctx_narrow_access_ok(off, size, size_default)) > return false; > } else { > + if (bpf_ctx_wide_store_ok(off, size, > + struct bpf_sock_addr, > + user_ip6)) > + return true; > + > + if (bpf_ctx_wide_store_ok(off, size, > + struct bpf_sock_addr, > + msg_src_ip6)) > + return true; > + > if (size != size_default) > return false; > } > @@ -7689,9 +7699,6 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > /* SOCK_ADDR_STORE_NESTED_FIELD_OFF() has semantic similar to > * SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF() but for store operation. > * > - * It doesn't support SIZE argument though since narrow stores are not > - * supported for now. > - * > * In addition it uses Temporary Field TF (member of struct S) as the 3rd > * "register" since two registers available in convert_ctx_access are not > * enough: we can't override neither SRC, since it contains value to store, nor > @@ -7699,7 +7706,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > * instructions. But we need a temporary place to save pointer to nested > * structure whose field we want to store to. > */ > -#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, TF) \ > +#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, OFF, TF) \ > do { \ > int tmp_reg = BPF_REG_9; \ > if (si->src_reg == tmp_reg || si->dst_reg == tmp_reg) \ > @@ -7710,8 +7717,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > offsetof(S, TF)); \ > *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(S, F), tmp_reg, \ > si->dst_reg, offsetof(S, F)); \ > - *insn++ = BPF_STX_MEM( \ > - BPF_FIELD_SIZEOF(NS, NF), tmp_reg, si->src_reg, \ > + *insn++ = BPF_STX_MEM(SIZE, tmp_reg, si->src_reg, \ > bpf_target_off(NS, NF, FIELD_SIZEOF(NS, NF), \ > target_size) \ > + OFF); \ > @@ -7723,8 +7729,8 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > TF) \ > do { \ > if (type == BPF_WRITE) { \ > - SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, \ > - TF); \ > + SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, \ > + OFF, TF); \ > } else { \ > SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF( \ > S, NS, F, NF, SIZE, OFF); \ > ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr 2019-06-30 5:52 ` [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr Yonghong Song @ 2019-07-01 15:36 ` Andrii Nakryiko 2019-07-01 16:04 ` Stanislav Fomichev 2019-07-01 16:01 ` Stanislav Fomichev 1 sibling, 1 reply; 11+ messages in thread From: Andrii Nakryiko @ 2019-07-01 15:36 UTC (permalink / raw) To: Yonghong Song Cc: Stanislav Fomichev, netdev, bpf, davem, ast, daniel, Andrii Nakryiko, kernel test robot On Sat, Jun 29, 2019 at 10:53 PM Yonghong Song <yhs@fb.com> wrote: > > > > On 6/28/19 4:10 PM, Stanislav Fomichev wrote: > > Since commit cd17d7770578 ("bpf/tools: sync bpf.h") clang decided > > that it can do a single u64 store into user_ip6[2] instead of two > > separate u32 ones: > > > > # 17: (18) r2 = 0x100000000000000 > > # ; ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2); > > # 19: (7b) *(u64 *)(r1 +16) = r2 > > # invalid bpf_context access off=16 size=8 > > > > From the compiler point of view it does look like a correct thing > > to do, so let's support it on the kernel side. > > > > Credit to Andrii Nakryiko for a proper implementation of > > bpf_ctx_wide_store_ok. > > > > Cc: Andrii Nakryiko <andriin@fb.com> > > Cc: Yonghong Song <yhs@fb.com> > > Fixes: cd17d7770578 ("bpf/tools: sync bpf.h") > > Reported-by: kernel test robot <rong.a.chen@intel.com> > > Signed-off-by: Stanislav Fomichev <sdf@google.com> > > The change looks good to me with the following nits: > 1. could you add a cover letter for the patch set? > typically if the number of patches is more than one, > it would be a good practice with a cover letter. > See bpf_devel_QA.rst . > 2. with this change, the comments in uapi bpf.h > are not accurate any more. > __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. > * Stored in network byte order. > > */ > __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. > * Stored in network byte order. > */ > now for stores, aligned 8-byte write is permitted. > could you update this as well? > > From the typical usage pattern, I did not see a need > for 8-tye read of user_ip6 and msg_src_ip6 yet. So let > us just deal with write for now. But I guess it's still possible for clang to optimize two consecutive 4-byte reads into single 8-byte read in some circumstances? If that's the case, maybe it's a good idea to have corresponding read checks as well? But overall this looks good to me: Acked-by: Andrii Nakryiko <andriin@fb.com> > > With the above two nits, > Acked-by: Yonghong Song <yhs@fb.com> > > > --- > > include/linux/filter.h | 6 ++++++ > > net/core/filter.c | 22 ++++++++++++++-------- > > 2 files changed, 20 insertions(+), 8 deletions(-) > > > > diff --git a/include/linux/filter.h b/include/linux/filter.h > > index 340f7d648974..3901007e36f1 100644 > > --- a/include/linux/filter.h > > +++ b/include/linux/filter.h > > @@ -746,6 +746,12 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default) > > return size <= size_default && (size & (size - 1)) == 0; > > } > > > > +#define bpf_ctx_wide_store_ok(off, size, type, field) \ > > + (size == sizeof(__u64) && \ > > + off >= offsetof(type, field) && \ > > + off + sizeof(__u64) <= offsetofend(type, field) && \ > > + off % sizeof(__u64) == 0) > > + > > #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) > > > > static inline void bpf_prog_lock_ro(struct bpf_prog *fp) > > diff --git a/net/core/filter.c b/net/core/filter.c > > index dc8534be12fc..5d33f2146dab 100644 > > --- a/net/core/filter.c > > +++ b/net/core/filter.c > > @@ -6849,6 +6849,16 @@ static bool sock_addr_is_valid_access(int off, int size, > > if (!bpf_ctx_narrow_access_ok(off, size, size_default)) > > return false; > > } else { > > + if (bpf_ctx_wide_store_ok(off, size, > > + struct bpf_sock_addr, > > + user_ip6)) > > + return true; > > + > > + if (bpf_ctx_wide_store_ok(off, size, > > + struct bpf_sock_addr, > > + msg_src_ip6)) > > + return true; > > + > > if (size != size_default) > > return false; > > } > > @@ -7689,9 +7699,6 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > > /* SOCK_ADDR_STORE_NESTED_FIELD_OFF() has semantic similar to > > * SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF() but for store operation. > > * > > - * It doesn't support SIZE argument though since narrow stores are not > > - * supported for now. > > - * > > * In addition it uses Temporary Field TF (member of struct S) as the 3rd > > * "register" since two registers available in convert_ctx_access are not > > * enough: we can't override neither SRC, since it contains value to store, nor > > @@ -7699,7 +7706,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > > * instructions. But we need a temporary place to save pointer to nested > > * structure whose field we want to store to. > > */ > > -#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, TF) \ > > +#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, OFF, TF) \ > > do { \ > > int tmp_reg = BPF_REG_9; \ > > if (si->src_reg == tmp_reg || si->dst_reg == tmp_reg) \ > > @@ -7710,8 +7717,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > > offsetof(S, TF)); \ > > *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(S, F), tmp_reg, \ > > si->dst_reg, offsetof(S, F)); \ > > - *insn++ = BPF_STX_MEM( \ > > - BPF_FIELD_SIZEOF(NS, NF), tmp_reg, si->src_reg, \ > > + *insn++ = BPF_STX_MEM(SIZE, tmp_reg, si->src_reg, \ > > bpf_target_off(NS, NF, FIELD_SIZEOF(NS, NF), \ > > target_size) \ > > + OFF); \ > > @@ -7723,8 +7729,8 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > > TF) \ > > do { \ > > if (type == BPF_WRITE) { \ > > - SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, \ > > - TF); \ > > + SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, \ > > + OFF, TF); \ > > } else { \ > > SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF( \ > > S, NS, F, NF, SIZE, OFF); \ > > ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr 2019-07-01 15:36 ` Andrii Nakryiko @ 2019-07-01 16:04 ` Stanislav Fomichev 2019-07-01 17:40 ` Yonghong Song 0 siblings, 1 reply; 11+ messages in thread From: Stanislav Fomichev @ 2019-07-01 16:04 UTC (permalink / raw) To: Andrii Nakryiko Cc: Yonghong Song, Stanislav Fomichev, netdev, bpf, davem, ast, daniel, Andrii Nakryiko, kernel test robot On 07/01, Andrii Nakryiko wrote: > On Sat, Jun 29, 2019 at 10:53 PM Yonghong Song <yhs@fb.com> wrote: > > > > > > > > On 6/28/19 4:10 PM, Stanislav Fomichev wrote: > > > Since commit cd17d7770578 ("bpf/tools: sync bpf.h") clang decided > > > that it can do a single u64 store into user_ip6[2] instead of two > > > separate u32 ones: > > > > > > # 17: (18) r2 = 0x100000000000000 > > > # ; ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2); > > > # 19: (7b) *(u64 *)(r1 +16) = r2 > > > # invalid bpf_context access off=16 size=8 > > > > > > From the compiler point of view it does look like a correct thing > > > to do, so let's support it on the kernel side. > > > > > > Credit to Andrii Nakryiko for a proper implementation of > > > bpf_ctx_wide_store_ok. > > > > > > Cc: Andrii Nakryiko <andriin@fb.com> > > > Cc: Yonghong Song <yhs@fb.com> > > > Fixes: cd17d7770578 ("bpf/tools: sync bpf.h") > > > Reported-by: kernel test robot <rong.a.chen@intel.com> > > > Signed-off-by: Stanislav Fomichev <sdf@google.com> > > > > The change looks good to me with the following nits: > > 1. could you add a cover letter for the patch set? > > typically if the number of patches is more than one, > > it would be a good practice with a cover letter. > > See bpf_devel_QA.rst . > > 2. with this change, the comments in uapi bpf.h > > are not accurate any more. > > __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. > > * Stored in network byte order. > > > > */ > > __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. > > * Stored in network byte order. > > */ > > now for stores, aligned 8-byte write is permitted. > > could you update this as well? > > > > From the typical usage pattern, I did not see a need > > for 8-tye read of user_ip6 and msg_src_ip6 yet. So let > > us just deal with write for now. > > But I guess it's still possible for clang to optimize two consecutive > 4-byte reads into single 8-byte read in some circumstances? If that's > the case, maybe it's a good idea to have corresponding read checks as > well? I guess clang can do those kinds of optimizations. I can put it on my todo and address later (or when we actually see it out in the wild). > But overall this looks good to me: > > Acked-by: Andrii Nakryiko <andriin@fb.com> Thanks for a review! > > > > With the above two nits, > > Acked-by: Yonghong Song <yhs@fb.com> > > > > > --- > > > include/linux/filter.h | 6 ++++++ > > > net/core/filter.c | 22 ++++++++++++++-------- > > > 2 files changed, 20 insertions(+), 8 deletions(-) > > > > > > diff --git a/include/linux/filter.h b/include/linux/filter.h > > > index 340f7d648974..3901007e36f1 100644 > > > --- a/include/linux/filter.h > > > +++ b/include/linux/filter.h > > > @@ -746,6 +746,12 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default) > > > return size <= size_default && (size & (size - 1)) == 0; > > > } > > > > > > +#define bpf_ctx_wide_store_ok(off, size, type, field) \ > > > + (size == sizeof(__u64) && \ > > > + off >= offsetof(type, field) && \ > > > + off + sizeof(__u64) <= offsetofend(type, field) && \ > > > + off % sizeof(__u64) == 0) > > > + > > > #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) > > > > > > static inline void bpf_prog_lock_ro(struct bpf_prog *fp) > > > diff --git a/net/core/filter.c b/net/core/filter.c > > > index dc8534be12fc..5d33f2146dab 100644 > > > --- a/net/core/filter.c > > > +++ b/net/core/filter.c > > > @@ -6849,6 +6849,16 @@ static bool sock_addr_is_valid_access(int off, int size, > > > if (!bpf_ctx_narrow_access_ok(off, size, size_default)) > > > return false; > > > } else { > > > + if (bpf_ctx_wide_store_ok(off, size, > > > + struct bpf_sock_addr, > > > + user_ip6)) > > > + return true; > > > + > > > + if (bpf_ctx_wide_store_ok(off, size, > > > + struct bpf_sock_addr, > > > + msg_src_ip6)) > > > + return true; > > > + > > > if (size != size_default) > > > return false; > > > } > > > @@ -7689,9 +7699,6 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > > > /* SOCK_ADDR_STORE_NESTED_FIELD_OFF() has semantic similar to > > > * SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF() but for store operation. > > > * > > > - * It doesn't support SIZE argument though since narrow stores are not > > > - * supported for now. > > > - * > > > * In addition it uses Temporary Field TF (member of struct S) as the 3rd > > > * "register" since two registers available in convert_ctx_access are not > > > * enough: we can't override neither SRC, since it contains value to store, nor > > > @@ -7699,7 +7706,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > > > * instructions. But we need a temporary place to save pointer to nested > > > * structure whose field we want to store to. > > > */ > > > -#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, TF) \ > > > +#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, OFF, TF) \ > > > do { \ > > > int tmp_reg = BPF_REG_9; \ > > > if (si->src_reg == tmp_reg || si->dst_reg == tmp_reg) \ > > > @@ -7710,8 +7717,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > > > offsetof(S, TF)); \ > > > *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(S, F), tmp_reg, \ > > > si->dst_reg, offsetof(S, F)); \ > > > - *insn++ = BPF_STX_MEM( \ > > > - BPF_FIELD_SIZEOF(NS, NF), tmp_reg, si->src_reg, \ > > > + *insn++ = BPF_STX_MEM(SIZE, tmp_reg, si->src_reg, \ > > > bpf_target_off(NS, NF, FIELD_SIZEOF(NS, NF), \ > > > target_size) \ > > > + OFF); \ > > > @@ -7723,8 +7729,8 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > > > TF) \ > > > do { \ > > > if (type == BPF_WRITE) { \ > > > - SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, \ > > > - TF); \ > > > + SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, \ > > > + OFF, TF); \ > > > } else { \ > > > SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF( \ > > > S, NS, F, NF, SIZE, OFF); \ > > > ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr 2019-07-01 16:04 ` Stanislav Fomichev @ 2019-07-01 17:40 ` Yonghong Song 2019-07-01 18:38 ` Stanislav Fomichev 0 siblings, 1 reply; 11+ messages in thread From: Yonghong Song @ 2019-07-01 17:40 UTC (permalink / raw) To: Stanislav Fomichev, Andrii Nakryiko Cc: Stanislav Fomichev, netdev, bpf, davem, ast, daniel, Andrii Nakryiko, kernel test robot On 7/1/19 9:04 AM, Stanislav Fomichev wrote: > On 07/01, Andrii Nakryiko wrote: >> On Sat, Jun 29, 2019 at 10:53 PM Yonghong Song <yhs@fb.com> wrote: >>> >>> >>> >>> On 6/28/19 4:10 PM, Stanislav Fomichev wrote: >>>> Since commit cd17d7770578 ("bpf/tools: sync bpf.h") clang decided >>>> that it can do a single u64 store into user_ip6[2] instead of two >>>> separate u32 ones: >>>> >>>> # 17: (18) r2 = 0x100000000000000 >>>> # ; ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2); >>>> # 19: (7b) *(u64 *)(r1 +16) = r2 >>>> # invalid bpf_context access off=16 size=8 >>>> >>>> From the compiler point of view it does look like a correct thing >>>> to do, so let's support it on the kernel side. >>>> >>>> Credit to Andrii Nakryiko for a proper implementation of >>>> bpf_ctx_wide_store_ok. >>>> >>>> Cc: Andrii Nakryiko <andriin@fb.com> >>>> Cc: Yonghong Song <yhs@fb.com> >>>> Fixes: cd17d7770578 ("bpf/tools: sync bpf.h") >>>> Reported-by: kernel test robot <rong.a.chen@intel.com> >>>> Signed-off-by: Stanislav Fomichev <sdf@google.com> >>> >>> The change looks good to me with the following nits: >>> 1. could you add a cover letter for the patch set? >>> typically if the number of patches is more than one, >>> it would be a good practice with a cover letter. >>> See bpf_devel_QA.rst . >>> 2. with this change, the comments in uapi bpf.h >>> are not accurate any more. >>> __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. >>> * Stored in network byte order. >>> >>> */ >>> __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. >>> * Stored in network byte order. >>> */ >>> now for stores, aligned 8-byte write is permitted. >>> could you update this as well? >>> >>> From the typical usage pattern, I did not see a need >>> for 8-tye read of user_ip6 and msg_src_ip6 yet. So let >>> us just deal with write for now. >> >> But I guess it's still possible for clang to optimize two consecutive >> 4-byte reads into single 8-byte read in some circumstances? If that's >> the case, maybe it's a good idea to have corresponding read checks as >> well? > I guess clang can do those kinds of optimizations. I can put it on my > todo and address later (or when we actually see it out in the wild). Okay, I find a Facebook internal app. does trying to read the 4 bytes and compare to a predefined loopback address. We may need to handle read cases as well. But this can be a followup after actual tryout. > >> But overall this looks good to me: >> >> Acked-by: Andrii Nakryiko <andriin@fb.com> > Thanks for a review! > >>> >>> With the above two nits, >>> Acked-by: Yonghong Song <yhs@fb.com> >>> >>>> --- >>>> include/linux/filter.h | 6 ++++++ >>>> net/core/filter.c | 22 ++++++++++++++-------- >>>> 2 files changed, 20 insertions(+), 8 deletions(-) >>>> >>>> diff --git a/include/linux/filter.h b/include/linux/filter.h >>>> index 340f7d648974..3901007e36f1 100644 >>>> --- a/include/linux/filter.h >>>> +++ b/include/linux/filter.h >>>> @@ -746,6 +746,12 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default) >>>> return size <= size_default && (size & (size - 1)) == 0; >>>> } >>>> >>>> +#define bpf_ctx_wide_store_ok(off, size, type, field) \ >>>> + (size == sizeof(__u64) && \ >>>> + off >= offsetof(type, field) && \ >>>> + off + sizeof(__u64) <= offsetofend(type, field) && \ >>>> + off % sizeof(__u64) == 0) >>>> + >>>> #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) >>>> >>>> static inline void bpf_prog_lock_ro(struct bpf_prog *fp) >>>> diff --git a/net/core/filter.c b/net/core/filter.c >>>> index dc8534be12fc..5d33f2146dab 100644 >>>> --- a/net/core/filter.c >>>> +++ b/net/core/filter.c >>>> @@ -6849,6 +6849,16 @@ static bool sock_addr_is_valid_access(int off, int size, >>>> if (!bpf_ctx_narrow_access_ok(off, size, size_default)) >>>> return false; >>>> } else { >>>> + if (bpf_ctx_wide_store_ok(off, size, >>>> + struct bpf_sock_addr, >>>> + user_ip6)) >>>> + return true; >>>> + >>>> + if (bpf_ctx_wide_store_ok(off, size, >>>> + struct bpf_sock_addr, >>>> + msg_src_ip6)) >>>> + return true; >>>> + >>>> if (size != size_default) >>>> return false; >>>> } >>>> @@ -7689,9 +7699,6 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, >>>> /* SOCK_ADDR_STORE_NESTED_FIELD_OFF() has semantic similar to >>>> * SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF() but for store operation. >>>> * >>>> - * It doesn't support SIZE argument though since narrow stores are not >>>> - * supported for now. >>>> - * >>>> * In addition it uses Temporary Field TF (member of struct S) as the 3rd >>>> * "register" since two registers available in convert_ctx_access are not >>>> * enough: we can't override neither SRC, since it contains value to store, nor >>>> @@ -7699,7 +7706,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, >>>> * instructions. But we need a temporary place to save pointer to nested >>>> * structure whose field we want to store to. >>>> */ >>>> -#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, TF) \ >>>> +#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, OFF, TF) \ >>>> do { \ >>>> int tmp_reg = BPF_REG_9; \ >>>> if (si->src_reg == tmp_reg || si->dst_reg == tmp_reg) \ >>>> @@ -7710,8 +7717,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, >>>> offsetof(S, TF)); \ >>>> *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(S, F), tmp_reg, \ >>>> si->dst_reg, offsetof(S, F)); \ >>>> - *insn++ = BPF_STX_MEM( \ >>>> - BPF_FIELD_SIZEOF(NS, NF), tmp_reg, si->src_reg, \ >>>> + *insn++ = BPF_STX_MEM(SIZE, tmp_reg, si->src_reg, \ >>>> bpf_target_off(NS, NF, FIELD_SIZEOF(NS, NF), \ >>>> target_size) \ >>>> + OFF); \ >>>> @@ -7723,8 +7729,8 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, >>>> TF) \ >>>> do { \ >>>> if (type == BPF_WRITE) { \ >>>> - SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, \ >>>> - TF); \ >>>> + SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, \ >>>> + OFF, TF); \ >>>> } else { \ >>>> SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF( \ >>>> S, NS, F, NF, SIZE, OFF); \ >>>> ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr 2019-07-01 17:40 ` Yonghong Song @ 2019-07-01 18:38 ` Stanislav Fomichev 0 siblings, 0 replies; 11+ messages in thread From: Stanislav Fomichev @ 2019-07-01 18:38 UTC (permalink / raw) To: Yonghong Song Cc: Andrii Nakryiko, Stanislav Fomichev, netdev, bpf, davem, ast, daniel, Andrii Nakryiko, kernel test robot On 07/01, Yonghong Song wrote: > > > On 7/1/19 9:04 AM, Stanislav Fomichev wrote: > > On 07/01, Andrii Nakryiko wrote: > >> On Sat, Jun 29, 2019 at 10:53 PM Yonghong Song <yhs@fb.com> wrote: > >>> > >>> > >>> > >>> On 6/28/19 4:10 PM, Stanislav Fomichev wrote: > >>>> Since commit cd17d7770578 ("bpf/tools: sync bpf.h") clang decided > >>>> that it can do a single u64 store into user_ip6[2] instead of two > >>>> separate u32 ones: > >>>> > >>>> # 17: (18) r2 = 0x100000000000000 > >>>> # ; ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2); > >>>> # 19: (7b) *(u64 *)(r1 +16) = r2 > >>>> # invalid bpf_context access off=16 size=8 > >>>> > >>>> From the compiler point of view it does look like a correct thing > >>>> to do, so let's support it on the kernel side. > >>>> > >>>> Credit to Andrii Nakryiko for a proper implementation of > >>>> bpf_ctx_wide_store_ok. > >>>> > >>>> Cc: Andrii Nakryiko <andriin@fb.com> > >>>> Cc: Yonghong Song <yhs@fb.com> > >>>> Fixes: cd17d7770578 ("bpf/tools: sync bpf.h") > >>>> Reported-by: kernel test robot <rong.a.chen@intel.com> > >>>> Signed-off-by: Stanislav Fomichev <sdf@google.com> > >>> > >>> The change looks good to me with the following nits: > >>> 1. could you add a cover letter for the patch set? > >>> typically if the number of patches is more than one, > >>> it would be a good practice with a cover letter. > >>> See bpf_devel_QA.rst . > >>> 2. with this change, the comments in uapi bpf.h > >>> are not accurate any more. > >>> __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. > >>> * Stored in network byte order. > >>> > >>> */ > >>> __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. > >>> * Stored in network byte order. > >>> */ > >>> now for stores, aligned 8-byte write is permitted. > >>> could you update this as well? > >>> > >>> From the typical usage pattern, I did not see a need > >>> for 8-tye read of user_ip6 and msg_src_ip6 yet. So let > >>> us just deal with write for now. > >> > >> But I guess it's still possible for clang to optimize two consecutive > >> 4-byte reads into single 8-byte read in some circumstances? If that's > >> the case, maybe it's a good idea to have corresponding read checks as > >> well? > > I guess clang can do those kinds of optimizations. I can put it on my > > todo and address later (or when we actually see it out in the wild). > > Okay, I find a Facebook internal app. does trying to read the 4 bytes > and compare to a predefined loopback address. We may need to handle > read cases as well. But this can be a followup after actual tryout. Sounds good, will follow up on that. > > > >> But overall this looks good to me: > >> > >> Acked-by: Andrii Nakryiko <andriin@fb.com> > > Thanks for a review! > > > >>> > >>> With the above two nits, > >>> Acked-by: Yonghong Song <yhs@fb.com> > >>> > >>>> --- > >>>> include/linux/filter.h | 6 ++++++ > >>>> net/core/filter.c | 22 ++++++++++++++-------- > >>>> 2 files changed, 20 insertions(+), 8 deletions(-) > >>>> > >>>> diff --git a/include/linux/filter.h b/include/linux/filter.h > >>>> index 340f7d648974..3901007e36f1 100644 > >>>> --- a/include/linux/filter.h > >>>> +++ b/include/linux/filter.h > >>>> @@ -746,6 +746,12 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default) > >>>> return size <= size_default && (size & (size - 1)) == 0; > >>>> } > >>>> > >>>> +#define bpf_ctx_wide_store_ok(off, size, type, field) \ > >>>> + (size == sizeof(__u64) && \ > >>>> + off >= offsetof(type, field) && \ > >>>> + off + sizeof(__u64) <= offsetofend(type, field) && \ > >>>> + off % sizeof(__u64) == 0) > >>>> + > >>>> #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) > >>>> > >>>> static inline void bpf_prog_lock_ro(struct bpf_prog *fp) > >>>> diff --git a/net/core/filter.c b/net/core/filter.c > >>>> index dc8534be12fc..5d33f2146dab 100644 > >>>> --- a/net/core/filter.c > >>>> +++ b/net/core/filter.c > >>>> @@ -6849,6 +6849,16 @@ static bool sock_addr_is_valid_access(int off, int size, > >>>> if (!bpf_ctx_narrow_access_ok(off, size, size_default)) > >>>> return false; > >>>> } else { > >>>> + if (bpf_ctx_wide_store_ok(off, size, > >>>> + struct bpf_sock_addr, > >>>> + user_ip6)) > >>>> + return true; > >>>> + > >>>> + if (bpf_ctx_wide_store_ok(off, size, > >>>> + struct bpf_sock_addr, > >>>> + msg_src_ip6)) > >>>> + return true; > >>>> + > >>>> if (size != size_default) > >>>> return false; > >>>> } > >>>> @@ -7689,9 +7699,6 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > >>>> /* SOCK_ADDR_STORE_NESTED_FIELD_OFF() has semantic similar to > >>>> * SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF() but for store operation. > >>>> * > >>>> - * It doesn't support SIZE argument though since narrow stores are not > >>>> - * supported for now. > >>>> - * > >>>> * In addition it uses Temporary Field TF (member of struct S) as the 3rd > >>>> * "register" since two registers available in convert_ctx_access are not > >>>> * enough: we can't override neither SRC, since it contains value to store, nor > >>>> @@ -7699,7 +7706,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > >>>> * instructions. But we need a temporary place to save pointer to nested > >>>> * structure whose field we want to store to. > >>>> */ > >>>> -#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, TF) \ > >>>> +#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, OFF, TF) \ > >>>> do { \ > >>>> int tmp_reg = BPF_REG_9; \ > >>>> if (si->src_reg == tmp_reg || si->dst_reg == tmp_reg) \ > >>>> @@ -7710,8 +7717,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > >>>> offsetof(S, TF)); \ > >>>> *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(S, F), tmp_reg, \ > >>>> si->dst_reg, offsetof(S, F)); \ > >>>> - *insn++ = BPF_STX_MEM( \ > >>>> - BPF_FIELD_SIZEOF(NS, NF), tmp_reg, si->src_reg, \ > >>>> + *insn++ = BPF_STX_MEM(SIZE, tmp_reg, si->src_reg, \ > >>>> bpf_target_off(NS, NF, FIELD_SIZEOF(NS, NF), \ > >>>> target_size) \ > >>>> + OFF); \ > >>>> @@ -7723,8 +7729,8 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > >>>> TF) \ > >>>> do { \ > >>>> if (type == BPF_WRITE) { \ > >>>> - SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, \ > >>>> - TF); \ > >>>> + SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, \ > >>>> + OFF, TF); \ > >>>> } else { \ > >>>> SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF( \ > >>>> S, NS, F, NF, SIZE, OFF); \ > >>>> ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr 2019-06-30 5:52 ` [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr Yonghong Song 2019-07-01 15:36 ` Andrii Nakryiko @ 2019-07-01 16:01 ` Stanislav Fomichev 1 sibling, 0 replies; 11+ messages in thread From: Stanislav Fomichev @ 2019-07-01 16:01 UTC (permalink / raw) To: Yonghong Song Cc: Stanislav Fomichev, netdev, bpf, davem, ast, daniel, Andrii Nakryiko, kernel test robot On 06/30, Yonghong Song wrote: > > > On 6/28/19 4:10 PM, Stanislav Fomichev wrote: > > Since commit cd17d7770578 ("bpf/tools: sync bpf.h") clang decided > > that it can do a single u64 store into user_ip6[2] instead of two > > separate u32 ones: > > > > # 17: (18) r2 = 0x100000000000000 > > # ; ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2); > > # 19: (7b) *(u64 *)(r1 +16) = r2 > > # invalid bpf_context access off=16 size=8 > > > > From the compiler point of view it does look like a correct thing > > to do, so let's support it on the kernel side. > > > > Credit to Andrii Nakryiko for a proper implementation of > > bpf_ctx_wide_store_ok. > > > > Cc: Andrii Nakryiko <andriin@fb.com> > > Cc: Yonghong Song <yhs@fb.com> > > Fixes: cd17d7770578 ("bpf/tools: sync bpf.h") > > Reported-by: kernel test robot <rong.a.chen@intel.com> > > Signed-off-by: Stanislav Fomichev <sdf@google.com> > > The change looks good to me with the following nits: > 1. could you add a cover letter for the patch set? > typically if the number of patches is more than one, > it would be a good practice with a cover letter. > See bpf_devel_QA.rst . > 2. with this change, the comments in uapi bpf.h > are not accurate any more. > __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. > * Stored in network byte order. > > */ > __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. > * Stored in network byte order. > */ > now for stores, aligned 8-byte write is permitted. > could you update this as well? > > From the typical usage pattern, I did not see a need > for 8-tye read of user_ip6 and msg_src_ip6 yet. So let > us just deal with write for now. > > With the above two nits, > Acked-by: Yonghong Song <yhs@fb.com> Thank you for a review, will follow up with a v2 shortly with both things addressed! > > --- > > include/linux/filter.h | 6 ++++++ > > net/core/filter.c | 22 ++++++++++++++-------- > > 2 files changed, 20 insertions(+), 8 deletions(-) > > > > diff --git a/include/linux/filter.h b/include/linux/filter.h > > index 340f7d648974..3901007e36f1 100644 > > --- a/include/linux/filter.h > > +++ b/include/linux/filter.h > > @@ -746,6 +746,12 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default) > > return size <= size_default && (size & (size - 1)) == 0; > > } > > > > +#define bpf_ctx_wide_store_ok(off, size, type, field) \ > > + (size == sizeof(__u64) && \ > > + off >= offsetof(type, field) && \ > > + off + sizeof(__u64) <= offsetofend(type, field) && \ > > + off % sizeof(__u64) == 0) > > + > > #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) > > > > static inline void bpf_prog_lock_ro(struct bpf_prog *fp) > > diff --git a/net/core/filter.c b/net/core/filter.c > > index dc8534be12fc..5d33f2146dab 100644 > > --- a/net/core/filter.c > > +++ b/net/core/filter.c > > @@ -6849,6 +6849,16 @@ static bool sock_addr_is_valid_access(int off, int size, > > if (!bpf_ctx_narrow_access_ok(off, size, size_default)) > > return false; > > } else { > > + if (bpf_ctx_wide_store_ok(off, size, > > + struct bpf_sock_addr, > > + user_ip6)) > > + return true; > > + > > + if (bpf_ctx_wide_store_ok(off, size, > > + struct bpf_sock_addr, > > + msg_src_ip6)) > > + return true; > > + > > if (size != size_default) > > return false; > > } > > @@ -7689,9 +7699,6 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > > /* SOCK_ADDR_STORE_NESTED_FIELD_OFF() has semantic similar to > > * SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF() but for store operation. > > * > > - * It doesn't support SIZE argument though since narrow stores are not > > - * supported for now. > > - * > > * In addition it uses Temporary Field TF (member of struct S) as the 3rd > > * "register" since two registers available in convert_ctx_access are not > > * enough: we can't override neither SRC, since it contains value to store, nor > > @@ -7699,7 +7706,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > > * instructions. But we need a temporary place to save pointer to nested > > * structure whose field we want to store to. > > */ > > -#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, TF) \ > > +#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, OFF, TF) \ > > do { \ > > int tmp_reg = BPF_REG_9; \ > > if (si->src_reg == tmp_reg || si->dst_reg == tmp_reg) \ > > @@ -7710,8 +7717,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > > offsetof(S, TF)); \ > > *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(S, F), tmp_reg, \ > > si->dst_reg, offsetof(S, F)); \ > > - *insn++ = BPF_STX_MEM( \ > > - BPF_FIELD_SIZEOF(NS, NF), tmp_reg, si->src_reg, \ > > + *insn++ = BPF_STX_MEM(SIZE, tmp_reg, si->src_reg, \ > > bpf_target_off(NS, NF, FIELD_SIZEOF(NS, NF), \ > > target_size) \ > > + OFF); \ > > @@ -7723,8 +7729,8 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, > > TF) \ > > do { \ > > if (type == BPF_WRITE) { \ > > - SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, \ > > - TF); \ > > + SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, \ > > + OFF, TF); \ > > } else { \ > > SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF( \ > > S, NS, F, NF, SIZE, OFF); \ > > ^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2019-07-01 18:39 UTC | newest] Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-06-28 23:10 [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr Stanislav Fomichev 2019-06-28 23:10 ` [PATCH bpf-next 2/2] selftests/bpf: add verifier tests for wide stores Stanislav Fomichev 2019-06-30 6:01 ` Yonghong Song 2019-07-01 15:44 ` Andrii Nakryiko 2019-07-01 16:00 ` Stanislav Fomichev 2019-06-30 5:52 ` [PATCH bpf-next 1/2] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr Yonghong Song 2019-07-01 15:36 ` Andrii Nakryiko 2019-07-01 16:04 ` Stanislav Fomichev 2019-07-01 17:40 ` Yonghong Song 2019-07-01 18:38 ` Stanislav Fomichev 2019-07-01 16:01 ` Stanislav Fomichev
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