* [bpf-next PATCH v2 0/2] SK_MSG programs: read sock fields
@ 2018-05-17 21:16 John Fastabend
2018-05-17 21:16 ` [bpf-next PATCH v2 1/2] bpf: allow sk_msg programs to " John Fastabend
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: John Fastabend @ 2018-05-17 21:16 UTC (permalink / raw)
To: ast, daniel; +Cc: netdev
In this series we add the ability for sk msg programs to read basic
sock information about the sock they are attached to. The second
patch adds the tests to the selftest test_verifier.
One obseration that I had from writing this seriess is lots of the
./net/core/filter.c code is almost duplicated across program types.
I thought about building a template/macro that we could use as a
single block of code to read sock data out for multiple programs,
but I wasn't convinced it was worth it yet. The result was using a
macro saved a couple lines of code per block but made the code
a bit harder to read IMO. We can probably revisit the idea later
if we get more duplication.
v2: add errstr field to negative test_verifier test cases to ensure
we get the expected err string back from the verifier.
---
John Fastabend (2):
bpf: allow sk_msg programs to read sock fields
bpf: add sk_msg prog sk access tests to test_verifier
include/linux/filter.h | 1
include/uapi/linux/bpf.h | 8 ++
kernel/bpf/sockmap.c | 1
net/core/filter.c | 114 ++++++++++++++++++++++++++-
tools/include/uapi/linux/bpf.h | 8 ++
tools/testing/selftests/bpf/test_verifier.c | 115 +++++++++++++++++++++++++++
6 files changed, 244 insertions(+), 3 deletions(-)
^ permalink raw reply [flat|nested] 4+ messages in thread
* [bpf-next PATCH v2 1/2] bpf: allow sk_msg programs to read sock fields
2018-05-17 21:16 [bpf-next PATCH v2 0/2] SK_MSG programs: read sock fields John Fastabend
@ 2018-05-17 21:16 ` John Fastabend
2018-05-17 21:17 ` [bpf-next PATCH v2 2/2] bpf: add sk_msg prog sk access tests to test_verifier John Fastabend
2018-05-18 21:11 ` [bpf-next PATCH v2 0/2] SK_MSG programs: read sock fields Daniel Borkmann
2 siblings, 0 replies; 4+ messages in thread
From: John Fastabend @ 2018-05-17 21:16 UTC (permalink / raw)
To: ast, daniel; +Cc: netdev
Currently sk_msg programs only have access to the raw data. However,
it is often useful when building policies to have the policies specific
to the socket endpoint. This allows using the socket tuple as input
into filters, etc.
This patch adds ctx access to the sock fields.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
include/linux/filter.h | 1
include/uapi/linux/bpf.h | 8 +++
kernel/bpf/sockmap.c | 1
net/core/filter.c | 114 +++++++++++++++++++++++++++++++++++++++++++++-
4 files changed, 121 insertions(+), 3 deletions(-)
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 9dbcb9d..d358d18 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -517,6 +517,7 @@ struct sk_msg_buff {
bool sg_copy[MAX_SKB_FRAGS];
__u32 flags;
struct sock *sk_redir;
+ struct sock *sk;
struct sk_buff *skb;
struct list_head list;
};
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index d94d333..97446bb 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2176,6 +2176,14 @@ enum sk_action {
struct sk_msg_md {
void *data;
void *data_end;
+
+ __u32 family;
+ __u32 remote_ip4; /* Stored in network byte order */
+ __u32 local_ip4; /* Stored in network byte order */
+ __u32 remote_ip6[4]; /* Stored in network byte order */
+ __u32 local_ip6[4]; /* Stored in network byte order */
+ __u32 remote_port; /* Stored in network byte order */
+ __u32 local_port; /* stored in host byte order */
};
#define BPF_TAG_SIZE 8
diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index c6de139..0ebf157 100644
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -523,6 +523,7 @@ static unsigned int smap_do_tx_msg(struct sock *sk,
}
bpf_compute_data_pointers_sg(md);
+ md->sk = sk;
rc = (*prog->bpf_func)(md, prog->insnsi);
psock->apply_bytes = md->apply_bytes;
diff --git a/net/core/filter.c b/net/core/filter.c
index 6d0d156..aec5eba 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5148,18 +5148,23 @@ static bool sk_msg_is_valid_access(int off, int size,
switch (off) {
case offsetof(struct sk_msg_md, data):
info->reg_type = PTR_TO_PACKET;
+ if (size != sizeof(__u64))
+ return false;
break;
case offsetof(struct sk_msg_md, data_end):
info->reg_type = PTR_TO_PACKET_END;
+ if (size != sizeof(__u64))
+ return false;
break;
+ default:
+ if (size != sizeof(__u32))
+ return false;
}
if (off < 0 || off >= sizeof(struct sk_msg_md))
return false;
if (off % size != 0)
return false;
- if (size != sizeof(__u64))
- return false;
return true;
}
@@ -5835,7 +5840,8 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type,
break;
case offsetof(struct bpf_sock_ops, local_ip4):
- BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common, skc_rcv_saddr) != 4);
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common,
+ skc_rcv_saddr) != 4);
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(
struct bpf_sock_ops_kern, sk),
@@ -6152,6 +6158,7 @@ static u32 sk_msg_convert_ctx_access(enum bpf_access_type type,
struct bpf_prog *prog, u32 *target_size)
{
struct bpf_insn *insn = insn_buf;
+ int off;
switch (si->off) {
case offsetof(struct sk_msg_md, data):
@@ -6164,6 +6171,107 @@ static u32 sk_msg_convert_ctx_access(enum bpf_access_type type,
si->dst_reg, si->src_reg,
offsetof(struct sk_msg_buff, data_end));
break;
+ case offsetof(struct sk_msg_md, family):
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common, skc_family) != 2);
+
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(
+ struct sk_msg_buff, sk),
+ si->dst_reg, si->src_reg,
+ offsetof(struct sk_msg_buff, sk));
+ *insn++ = BPF_LDX_MEM(BPF_H, si->dst_reg, si->dst_reg,
+ offsetof(struct sock_common, skc_family));
+ break;
+
+ case offsetof(struct sk_msg_md, remote_ip4):
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common, skc_daddr) != 4);
+
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(
+ struct sk_msg_buff, sk),
+ si->dst_reg, si->src_reg,
+ offsetof(struct sk_msg_buff, sk));
+ *insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->dst_reg,
+ offsetof(struct sock_common, skc_daddr));
+ break;
+
+ case offsetof(struct sk_msg_md, local_ip4):
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common,
+ skc_rcv_saddr) != 4);
+
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(
+ struct sk_msg_buff, sk),
+ si->dst_reg, si->src_reg,
+ offsetof(struct sk_msg_buff, sk));
+ *insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->dst_reg,
+ offsetof(struct sock_common,
+ skc_rcv_saddr));
+ break;
+
+ case offsetof(struct sk_msg_md, remote_ip6[0]) ...
+ offsetof(struct sk_msg_md, remote_ip6[3]):
+#if IS_ENABLED(CONFIG_IPV6)
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common,
+ skc_v6_daddr.s6_addr32[0]) != 4);
+
+ off = si->off;
+ off -= offsetof(struct sk_msg_md, remote_ip6[0]);
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(
+ struct sk_msg_buff, sk),
+ si->dst_reg, si->src_reg,
+ offsetof(struct sk_msg_buff, sk));
+ *insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->dst_reg,
+ offsetof(struct sock_common,
+ skc_v6_daddr.s6_addr32[0]) +
+ off);
+#else
+ *insn++ = BPF_MOV32_IMM(si->dst_reg, 0);
+#endif
+ break;
+
+ case offsetof(struct sk_msg_md, local_ip6[0]) ...
+ offsetof(struct sk_msg_md, local_ip6[3]):
+#if IS_ENABLED(CONFIG_IPV6)
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common,
+ skc_v6_rcv_saddr.s6_addr32[0]) != 4);
+
+ off = si->off;
+ off -= offsetof(struct sk_msg_md, local_ip6[0]);
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(
+ struct sk_msg_buff, sk),
+ si->dst_reg, si->src_reg,
+ offsetof(struct sk_msg_buff, sk));
+ *insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->dst_reg,
+ offsetof(struct sock_common,
+ skc_v6_rcv_saddr.s6_addr32[0]) +
+ off);
+#else
+ *insn++ = BPF_MOV32_IMM(si->dst_reg, 0);
+#endif
+ break;
+
+ case offsetof(struct sk_msg_md, remote_port):
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common, skc_dport) != 2);
+
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(
+ struct sk_msg_buff, sk),
+ si->dst_reg, si->src_reg,
+ offsetof(struct sk_msg_buff, sk));
+ *insn++ = BPF_LDX_MEM(BPF_H, si->dst_reg, si->dst_reg,
+ offsetof(struct sock_common, skc_dport));
+#ifndef __BIG_ENDIAN_BITFIELD
+ *insn++ = BPF_ALU32_IMM(BPF_LSH, si->dst_reg, 16);
+#endif
+ break;
+
+ case offsetof(struct sk_msg_md, local_port):
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sock_common, skc_num) != 2);
+
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(
+ struct sk_msg_buff, sk),
+ si->dst_reg, si->src_reg,
+ offsetof(struct sk_msg_buff, sk));
+ *insn++ = BPF_LDX_MEM(BPF_H, si->dst_reg, si->dst_reg,
+ offsetof(struct sock_common, skc_num));
+ break;
}
return insn - insn_buf;
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [bpf-next PATCH v2 2/2] bpf: add sk_msg prog sk access tests to test_verifier
2018-05-17 21:16 [bpf-next PATCH v2 0/2] SK_MSG programs: read sock fields John Fastabend
2018-05-17 21:16 ` [bpf-next PATCH v2 1/2] bpf: allow sk_msg programs to " John Fastabend
@ 2018-05-17 21:17 ` John Fastabend
2018-05-18 21:11 ` [bpf-next PATCH v2 0/2] SK_MSG programs: read sock fields Daniel Borkmann
2 siblings, 0 replies; 4+ messages in thread
From: John Fastabend @ 2018-05-17 21:17 UTC (permalink / raw)
To: ast, daniel; +Cc: netdev
Add tests for BPF_PROG_TYPE_SK_MSG to test_verifier for read access
to new sk fields.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
tools/include/uapi/linux/bpf.h | 8 ++
tools/testing/selftests/bpf/test_verifier.c | 115 +++++++++++++++++++++++++++
2 files changed, 123 insertions(+)
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index d94d333..97446bb 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -2176,6 +2176,14 @@ enum sk_action {
struct sk_msg_md {
void *data;
void *data_end;
+
+ __u32 family;
+ __u32 remote_ip4; /* Stored in network byte order */
+ __u32 local_ip4; /* Stored in network byte order */
+ __u32 remote_ip6[4]; /* Stored in network byte order */
+ __u32 local_ip6[4]; /* Stored in network byte order */
+ __u32 remote_port; /* Stored in network byte order */
+ __u32 local_port; /* stored in host byte order */
};
#define BPF_TAG_SIZE 8
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index a877af0..6ec4d9d 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -1686,6 +1686,121 @@ static void bpf_fill_rand_ld_dw(struct bpf_test *self)
.prog_type = BPF_PROG_TYPE_SK_SKB,
},
{
+ "valid access family in SK_MSG",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct sk_msg_md, family)),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_SK_MSG,
+ },
+ {
+ "valid access remote_ip4 in SK_MSG",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct sk_msg_md, remote_ip4)),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_SK_MSG,
+ },
+ {
+ "valid access local_ip4 in SK_MSG",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct sk_msg_md, local_ip4)),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_SK_MSG,
+ },
+ {
+ "valid access remote_port in SK_MSG",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct sk_msg_md, remote_port)),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_SK_MSG,
+ },
+ {
+ "valid access local_port in SK_MSG",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct sk_msg_md, local_port)),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_SK_MSG,
+ },
+ {
+ "valid access remote_ip6 in SK_MSG",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct sk_msg_md, remote_ip6[0])),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct sk_msg_md, remote_ip6[1])),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct sk_msg_md, remote_ip6[2])),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct sk_msg_md, remote_ip6[3])),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_SK_SKB,
+ },
+ {
+ "valid access local_ip6 in SK_MSG",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct sk_msg_md, local_ip6[0])),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct sk_msg_md, local_ip6[1])),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct sk_msg_md, local_ip6[2])),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct sk_msg_md, local_ip6[3])),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_SK_SKB,
+ },
+ {
+ "invalid 64B read of family in SK_MSG",
+ .insns = {
+ BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1,
+ offsetof(struct sk_msg_md, family)),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_MSG,
+ },
+ {
+ "invalid read past end of SK_MSG",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+ offsetof(struct sk_msg_md, local_port) + 4),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R0 !read_ok",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_MSG,
+ },
+ {
+ "invalid read offset in SK_MSG",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+ offsetof(struct sk_msg_md, family) + 1),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_MSG,
+ },
+ {
"direct packet read for SK_MSG",
.insns = {
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1,
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [bpf-next PATCH v2 0/2] SK_MSG programs: read sock fields
2018-05-17 21:16 [bpf-next PATCH v2 0/2] SK_MSG programs: read sock fields John Fastabend
2018-05-17 21:16 ` [bpf-next PATCH v2 1/2] bpf: allow sk_msg programs to " John Fastabend
2018-05-17 21:17 ` [bpf-next PATCH v2 2/2] bpf: add sk_msg prog sk access tests to test_verifier John Fastabend
@ 2018-05-18 21:11 ` Daniel Borkmann
2 siblings, 0 replies; 4+ messages in thread
From: Daniel Borkmann @ 2018-05-18 21:11 UTC (permalink / raw)
To: John Fastabend, ast; +Cc: netdev
On 05/17/2018 11:16 PM, John Fastabend wrote:
> In this series we add the ability for sk msg programs to read basic
> sock information about the sock they are attached to. The second
> patch adds the tests to the selftest test_verifier.
>
> One obseration that I had from writing this seriess is lots of the
> ./net/core/filter.c code is almost duplicated across program types.
> I thought about building a template/macro that we could use as a
> single block of code to read sock data out for multiple programs,
> but I wasn't convinced it was worth it yet. The result was using a
> macro saved a couple lines of code per block but made the code
> a bit harder to read IMO. We can probably revisit the idea later
> if we get more duplication.
>
> v2: add errstr field to negative test_verifier test cases to ensure
> we get the expected err string back from the verifier.
>
> ---
>
> John Fastabend (2):
> bpf: allow sk_msg programs to read sock fields
> bpf: add sk_msg prog sk access tests to test_verifier
>
>
> include/linux/filter.h | 1
> include/uapi/linux/bpf.h | 8 ++
> kernel/bpf/sockmap.c | 1
> net/core/filter.c | 114 ++++++++++++++++++++++++++-
> tools/include/uapi/linux/bpf.h | 8 ++
> tools/testing/selftests/bpf/test_verifier.c | 115 +++++++++++++++++++++++++++
> 6 files changed, 244 insertions(+), 3 deletions(-)
>
> --
> Signature
>
Applied to bpf-next, thanks John!
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-05-18 21:11 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2018-05-17 21:16 [bpf-next PATCH v2 0/2] SK_MSG programs: read sock fields John Fastabend
2018-05-17 21:16 ` [bpf-next PATCH v2 1/2] bpf: allow sk_msg programs to " John Fastabend
2018-05-17 21:17 ` [bpf-next PATCH v2 2/2] bpf: add sk_msg prog sk access tests to test_verifier John Fastabend
2018-05-18 21:11 ` [bpf-next PATCH v2 0/2] SK_MSG programs: read sock fields Daniel Borkmann
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