* [PATCH bpf-next v2 0/3] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr
@ 2019-07-01 16:31 Stanislav Fomichev
2019-07-01 16:31 ` [PATCH bpf-next v2 1/3] " Stanislav Fomichev
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Stanislav Fomichev @ 2019-07-01 16:31 UTC (permalink / raw)
To: netdev, bpf; +Cc: davem, ast, daniel, Stanislav Fomichev
Clang can generate 8-byte stores for user_ip6 & msg_src_ip6,
let's support that on the verifier side.
v2:
* Add simple cover letter (Yonghong Song)
* Update comments (Yonghong Song)
* Remove [4] selftests (Yonghong Song)
Stanislav Fomichev (3):
bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr
bpf: sync bpf.h to tools/
selftests/bpf: add verifier tests for wide stores
include/linux/filter.h | 6 ++++
include/uapi/linux/bpf.h | 4 +--
net/core/filter.c | 22 +++++++-----
tools/include/uapi/linux/bpf.h | 4 +--
tools/testing/selftests/bpf/test_verifier.c | 17 +++++++--
.../selftests/bpf/verifier/wide_store.c | 36 +++++++++++++++++++
6 files changed, 74 insertions(+), 15 deletions(-)
create mode 100644 tools/testing/selftests/bpf/verifier/wide_store.c
--
2.22.0.410.gd8fdbe21b5-goog
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH bpf-next v2 1/3] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr
2019-07-01 16:31 [PATCH bpf-next v2 0/3] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr Stanislav Fomichev
@ 2019-07-01 16:31 ` Stanislav Fomichev
2019-07-01 16:54 ` Andrii Nakryiko
2019-07-01 16:31 ` [PATCH bpf-next v2 2/3] bpf: sync bpf.h to tools/ Stanislav Fomichev
2019-07-01 16:31 ` [PATCH bpf-next v2 3/3] selftests/bpf: add verifier tests for wide stores Stanislav Fomichev
2 siblings, 1 reply; 7+ messages in thread
From: Stanislav Fomichev @ 2019-07-01 16:31 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>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
include/linux/filter.h | 6 ++++++
include/uapi/linux/bpf.h | 4 ++--
net/core/filter.c | 22 ++++++++++++++--------
3 files changed, 22 insertions(+), 10 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/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index a396b516a2b2..586867fe6102 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3237,7 +3237,7 @@ struct bpf_sock_addr {
__u32 user_ip4; /* Allows 1,2,4-byte read and 4-byte write.
* Stored in network byte order.
*/
- __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write.
+ __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4,8-byte write.
* Stored in network byte order.
*/
__u32 user_port; /* Allows 4-byte read and write.
@@ -3249,7 +3249,7 @@ struct bpf_sock_addr {
__u32 msg_src_ip4; /* 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.
+ __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4,8-byte write.
* Stored in network byte order.
*/
__bpf_md_ptr(struct bpf_sock *, sk);
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] 7+ messages in thread
* [PATCH bpf-next v2 2/3] bpf: sync bpf.h to tools/
2019-07-01 16:31 [PATCH bpf-next v2 0/3] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr Stanislav Fomichev
2019-07-01 16:31 ` [PATCH bpf-next v2 1/3] " Stanislav Fomichev
@ 2019-07-01 16:31 ` Stanislav Fomichev
2019-07-01 16:31 ` [PATCH bpf-next v2 3/3] selftests/bpf: add verifier tests for wide stores Stanislav Fomichev
2 siblings, 0 replies; 7+ messages in thread
From: Stanislav Fomichev @ 2019-07-01 16:31 UTC (permalink / raw)
To: netdev, bpf; +Cc: davem, ast, daniel, Stanislav Fomichev
Sync user_ip6 & msg_src_ip6 comments.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
tools/include/uapi/linux/bpf.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index a396b516a2b2..586867fe6102 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3237,7 +3237,7 @@ struct bpf_sock_addr {
__u32 user_ip4; /* Allows 1,2,4-byte read and 4-byte write.
* Stored in network byte order.
*/
- __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write.
+ __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4,8-byte write.
* Stored in network byte order.
*/
__u32 user_port; /* Allows 4-byte read and write.
@@ -3249,7 +3249,7 @@ struct bpf_sock_addr {
__u32 msg_src_ip4; /* 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.
+ __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4,8-byte write.
* Stored in network byte order.
*/
__bpf_md_ptr(struct bpf_sock *, sk);
--
2.22.0.410.gd8fdbe21b5-goog
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH bpf-next v2 3/3] selftests/bpf: add verifier tests for wide stores
2019-07-01 16:31 [PATCH bpf-next v2 0/3] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr Stanislav Fomichev
2019-07-01 16:31 ` [PATCH bpf-next v2 1/3] " Stanislav Fomichev
2019-07-01 16:31 ` [PATCH bpf-next v2 2/3] bpf: sync bpf.h to tools/ Stanislav Fomichev
@ 2019-07-01 16:31 ` Stanislav Fomichev
2019-07-01 16:55 ` Andrii Nakryiko
2 siblings, 1 reply; 7+ messages in thread
From: Stanislav Fomichev @ 2019-07-01 16:31 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 | 36 +++++++++++++++++++
2 files changed, 50 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..8fe99602ded4
--- /dev/null
+++ b/tools/testing/selftests/bpf/verifier/wide_store.c
@@ -0,0 +1,36 @@
+#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"),
+
+/* 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"),
+
+#undef BPF_SOCK_ADDR
--
2.22.0.410.gd8fdbe21b5-goog
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH bpf-next v2 1/3] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr
2019-07-01 16:31 ` [PATCH bpf-next v2 1/3] " Stanislav Fomichev
@ 2019-07-01 16:54 ` Andrii Nakryiko
2019-07-01 17:34 ` Stanislav Fomichev
0 siblings, 1 reply; 7+ messages in thread
From: Andrii Nakryiko @ 2019-07-01 16:54 UTC (permalink / raw)
To: Stanislav Fomichev
Cc: Networking, bpf, David S. Miller, Alexei Starovoitov,
Daniel Borkmann, Andrii Nakryiko, Yonghong Song,
kernel test robot
On Mon, Jul 1, 2019 at 9:51 AM Stanislav Fomichev <sdf@google.com> 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>
> Acked-by: Yonghong Song <yhs@fb.com>
> Acked-by: Andrii Nakryiko <andriin@fb.com>
> Signed-off-by: Stanislav Fomichev <sdf@google.com>
> ---
> include/linux/filter.h | 6 ++++++
> include/uapi/linux/bpf.h | 4 ++--
> net/core/filter.c | 22 ++++++++++++++--------
> 3 files changed, 22 insertions(+), 10 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/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index a396b516a2b2..586867fe6102 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -3237,7 +3237,7 @@ struct bpf_sock_addr {
> __u32 user_ip4; /* Allows 1,2,4-byte read and 4-byte write.
> * Stored in network byte order.
> */
> - __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write.
> + __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4,8-byte write.
typo: an -> and
> * Stored in network byte order.
> */
> __u32 user_port; /* Allows 4-byte read and write.
> @@ -3249,7 +3249,7 @@ struct bpf_sock_addr {
> __u32 msg_src_ip4; /* Allows 1,2,4-byte read an 4-byte write.
same
> * Stored in network byte order.
> */
> - __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write.
> + __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4,8-byte write.
the power of copy/paste! :)
> * Stored in network byte order.
> */
> __bpf_md_ptr(struct bpf_sock *, sk);
> 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 [flat|nested] 7+ messages in thread
* Re: [PATCH bpf-next v2 3/3] selftests/bpf: add verifier tests for wide stores
2019-07-01 16:31 ` [PATCH bpf-next v2 3/3] selftests/bpf: add verifier tests for wide stores Stanislav Fomichev
@ 2019-07-01 16:55 ` Andrii Nakryiko
0 siblings, 0 replies; 7+ messages in thread
From: Andrii Nakryiko @ 2019-07-01 16:55 UTC (permalink / raw)
To: Stanislav Fomichev
Cc: Networking, bpf, David S. Miller, Alexei Starovoitov,
Daniel Borkmann, Andrii Nakryiko, Yonghong Song
On Mon, Jul 1, 2019 at 9:54 AM Stanislav Fomichev <sdf@google.com> 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>
> ---
Acked-by: Andrii Nakryiko <andriin@fb.com>
> tools/testing/selftests/bpf/test_verifier.c | 17 +++++++--
> .../selftests/bpf/verifier/wide_store.c | 36 +++++++++++++++++++
> 2 files changed, 50 insertions(+), 3 deletions(-)
> create mode 100644 tools/testing/selftests/bpf/verifier/wide_store.c
>
<snip>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH bpf-next v2 1/3] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr
2019-07-01 16:54 ` Andrii Nakryiko
@ 2019-07-01 17:34 ` Stanislav Fomichev
0 siblings, 0 replies; 7+ messages in thread
From: Stanislav Fomichev @ 2019-07-01 17:34 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Stanislav Fomichev, Networking, bpf, David S. Miller,
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Yonghong Song, kernel test robot
On 07/01, Andrii Nakryiko wrote:
> On Mon, Jul 1, 2019 at 9:51 AM Stanislav Fomichev <sdf@google.com> 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>
> > Acked-by: Yonghong Song <yhs@fb.com>
> > Acked-by: Andrii Nakryiko <andriin@fb.com>
> > Signed-off-by: Stanislav Fomichev <sdf@google.com>
> > ---
> > include/linux/filter.h | 6 ++++++
> > include/uapi/linux/bpf.h | 4 ++--
> > net/core/filter.c | 22 ++++++++++++++--------
> > 3 files changed, 22 insertions(+), 10 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/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> > index a396b516a2b2..586867fe6102 100644
> > --- a/include/uapi/linux/bpf.h
> > +++ b/include/uapi/linux/bpf.h
> > @@ -3237,7 +3237,7 @@ struct bpf_sock_addr {
> > __u32 user_ip4; /* Allows 1,2,4-byte read and 4-byte write.
> > * Stored in network byte order.
> > */
> > - __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write.
> > + __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4,8-byte write.
>
> typo: an -> and
Oh, I was thinking that it was an article :-/
Will send a v3 with a fix, thanks!
> > * Stored in network byte order.
> > */
> > __u32 user_port; /* Allows 4-byte read and write.
> > @@ -3249,7 +3249,7 @@ struct bpf_sock_addr {
> > __u32 msg_src_ip4; /* Allows 1,2,4-byte read an 4-byte write.
>
> same
>
> > * Stored in network byte order.
> > */
> > - __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write.
> > + __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4,8-byte write.
>
> the power of copy/paste! :)
>
> > * Stored in network byte order.
> > */
> > __bpf_md_ptr(struct bpf_sock *, sk);
> > 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 [flat|nested] 7+ messages in thread
end of thread, other threads:[~2019-07-01 17:34 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
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2019-07-01 16:31 [PATCH bpf-next v2 0/3] bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr Stanislav Fomichev
2019-07-01 16:31 ` [PATCH bpf-next v2 1/3] " Stanislav Fomichev
2019-07-01 16:54 ` Andrii Nakryiko
2019-07-01 17:34 ` Stanislav Fomichev
2019-07-01 16:31 ` [PATCH bpf-next v2 2/3] bpf: sync bpf.h to tools/ Stanislav Fomichev
2019-07-01 16:31 ` [PATCH bpf-next v2 3/3] selftests/bpf: add verifier tests for wide stores Stanislav Fomichev
2019-07-01 16:55 ` Andrii Nakryiko
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