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* [PATCH bpf-next v1] bpf: Add flags arg to bpf_dynptr_read and bpf_dynptr_write APIs
@ 2022-07-06 23:25 Joanne Koong
  2022-07-07 19:52 ` Alexei Starovoitov
  2022-07-08  0:20 ` patchwork-bot+netdevbpf
  0 siblings, 2 replies; 3+ messages in thread
From: Joanne Koong @ 2022-07-06 23:25 UTC (permalink / raw)
  To: bpf; +Cc: andrii, daniel, ast, Joanne Koong

Commit 13bbbfbea759 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write")
added the bpf_dynptr_write and bpf_dynptr_read APIs.

However, it will be useful for some dynptr types to pass in flags as
well (eg when writing to a skb, the user may like to invalidate the
hash or recompute the checksum).

This patch adds a "u64 flags" arg to the bpf_dynptr_read and
bpf_dynptr_write APIs.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Fixes: 13bbbfbea759 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write")
---
 include/uapi/linux/bpf.h                           | 11 +++++++----
 kernel/bpf/helpers.c                               | 12 ++++++++----
 tools/include/uapi/linux/bpf.h                     | 11 +++++++----
 tools/testing/selftests/bpf/progs/dynptr_fail.c    | 10 +++++-----
 tools/testing/selftests/bpf/progs/dynptr_success.c |  4 ++--
 5 files changed, 29 insertions(+), 19 deletions(-)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 379e68fb866f..3dd13fe738b9 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5226,22 +5226,25 @@ union bpf_attr {
  *	Return
  *		Nothing. Always succeeds.
  *
- * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset)
+ * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset, u64 flags)
  *	Description
  *		Read *len* bytes from *src* into *dst*, starting from *offset*
  *		into *src*.
+ *		*flags* is currently unused.
  *	Return
  *		0 on success, -E2BIG if *offset* + *len* exceeds the length
- *		of *src*'s data, -EINVAL if *src* is an invalid dynptr.
+ *		of *src*'s data, -EINVAL if *src* is an invalid dynptr or if
+ *		*flags* is not 0.
  *
- * long bpf_dynptr_write(struct bpf_dynptr *dst, u32 offset, void *src, u32 len)
+ * long bpf_dynptr_write(struct bpf_dynptr *dst, u32 offset, void *src, u32 len, u64 flags)
  *	Description
  *		Write *len* bytes from *src* into *dst*, starting from *offset*
  *		into *dst*.
+ *		*flags* is currently unused.
  *	Return
  *		0 on success, -E2BIG if *offset* + *len* exceeds the length
  *		of *dst*'s data, -EINVAL if *dst* is an invalid dynptr or if *dst*
- *		is a read-only dynptr.
+ *		is a read-only dynptr or if *flags* is not 0.
  *
  * void *bpf_dynptr_data(struct bpf_dynptr *ptr, u32 offset, u32 len)
  *	Description
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index a1c84d256f83..1f961f9982d2 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -1497,11 +1497,12 @@ static const struct bpf_func_proto bpf_dynptr_from_mem_proto = {
 	.arg4_type	= ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL | MEM_UNINIT,
 };
 
-BPF_CALL_4(bpf_dynptr_read, void *, dst, u32, len, struct bpf_dynptr_kern *, src, u32, offset)
+BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, struct bpf_dynptr_kern *, src,
+	   u32, offset, u64, flags)
 {
 	int err;
 
-	if (!src->data)
+	if (!src->data || flags)
 		return -EINVAL;
 
 	err = bpf_dynptr_check_off_len(src, offset, len);
@@ -1521,13 +1522,15 @@ static const struct bpf_func_proto bpf_dynptr_read_proto = {
 	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
 	.arg3_type	= ARG_PTR_TO_DYNPTR,
 	.arg4_type	= ARG_ANYTHING,
+	.arg5_type	= ARG_ANYTHING,
 };
 
-BPF_CALL_4(bpf_dynptr_write, struct bpf_dynptr_kern *, dst, u32, offset, void *, src, u32, len)
+BPF_CALL_5(bpf_dynptr_write, struct bpf_dynptr_kern *, dst, u32, offset, void *, src,
+	   u32, len, u64, flags)
 {
 	int err;
 
-	if (!dst->data || bpf_dynptr_is_rdonly(dst))
+	if (!dst->data || flags || bpf_dynptr_is_rdonly(dst))
 		return -EINVAL;
 
 	err = bpf_dynptr_check_off_len(dst, offset, len);
@@ -1547,6 +1550,7 @@ static const struct bpf_func_proto bpf_dynptr_write_proto = {
 	.arg2_type	= ARG_ANYTHING,
 	.arg3_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
 	.arg4_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg5_type	= ARG_ANYTHING,
 };
 
 BPF_CALL_3(bpf_dynptr_data, struct bpf_dynptr_kern *, ptr, u32, offset, u32, len)
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 379e68fb866f..3dd13fe738b9 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -5226,22 +5226,25 @@ union bpf_attr {
  *	Return
  *		Nothing. Always succeeds.
  *
- * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset)
+ * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset, u64 flags)
  *	Description
  *		Read *len* bytes from *src* into *dst*, starting from *offset*
  *		into *src*.
+ *		*flags* is currently unused.
  *	Return
  *		0 on success, -E2BIG if *offset* + *len* exceeds the length
- *		of *src*'s data, -EINVAL if *src* is an invalid dynptr.
+ *		of *src*'s data, -EINVAL if *src* is an invalid dynptr or if
+ *		*flags* is not 0.
  *
- * long bpf_dynptr_write(struct bpf_dynptr *dst, u32 offset, void *src, u32 len)
+ * long bpf_dynptr_write(struct bpf_dynptr *dst, u32 offset, void *src, u32 len, u64 flags)
  *	Description
  *		Write *len* bytes from *src* into *dst*, starting from *offset*
  *		into *dst*.
+ *		*flags* is currently unused.
  *	Return
  *		0 on success, -E2BIG if *offset* + *len* exceeds the length
  *		of *dst*'s data, -EINVAL if *dst* is an invalid dynptr or if *dst*
- *		is a read-only dynptr.
+ *		is a read-only dynptr or if *flags* is not 0.
  *
  * void *bpf_dynptr_data(struct bpf_dynptr *ptr, u32 offset, u32 len)
  *	Description
diff --git a/tools/testing/selftests/bpf/progs/dynptr_fail.c b/tools/testing/selftests/bpf/progs/dynptr_fail.c
index d811cff73597..0a26c243e6e9 100644
--- a/tools/testing/selftests/bpf/progs/dynptr_fail.c
+++ b/tools/testing/selftests/bpf/progs/dynptr_fail.c
@@ -140,12 +140,12 @@ int use_after_invalid(void *ctx)
 
 	bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(read_data), 0, &ptr);
 
-	bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0);
+	bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0, 0);
 
 	bpf_ringbuf_submit_dynptr(&ptr, 0);
 
 	/* this should fail */
-	bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0);
+	bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0, 0);
 
 	return 0;
 }
@@ -338,7 +338,7 @@ int invalid_helper2(void *ctx)
 	get_map_val_dynptr(&ptr);
 
 	/* this should fail */
-	bpf_dynptr_read(read_data, sizeof(read_data), (void *)&ptr + 8, 0);
+	bpf_dynptr_read(read_data, sizeof(read_data), (void *)&ptr + 8, 0, 0);
 
 	return 0;
 }
@@ -377,7 +377,7 @@ int invalid_write2(void *ctx)
 	memcpy((void *)&ptr + 8, &x, sizeof(x));
 
 	/* this should fail */
-	bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0);
+	bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0, 0);
 
 	bpf_ringbuf_submit_dynptr(&ptr, 0);
 
@@ -473,7 +473,7 @@ int invalid_read2(void *ctx)
 	get_map_val_dynptr(&ptr);
 
 	/* this should fail */
-	bpf_dynptr_read(read_data, sizeof(read_data), (void *)&ptr + 1, 0);
+	bpf_dynptr_read(read_data, sizeof(read_data), (void *)&ptr + 1, 0, 0);
 
 	return 0;
 }
diff --git a/tools/testing/selftests/bpf/progs/dynptr_success.c b/tools/testing/selftests/bpf/progs/dynptr_success.c
index d67be48df4b2..a3a6103c8569 100644
--- a/tools/testing/selftests/bpf/progs/dynptr_success.c
+++ b/tools/testing/selftests/bpf/progs/dynptr_success.c
@@ -43,10 +43,10 @@ int test_read_write(void *ctx)
 	bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(write_data), 0, &ptr);
 
 	/* Write data into the dynptr */
-	err = err ?: bpf_dynptr_write(&ptr, 0, write_data, sizeof(write_data));
+	err = bpf_dynptr_write(&ptr, 0, write_data, sizeof(write_data), 0);
 
 	/* Read the data that was written into the dynptr */
-	err = err ?: bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0);
+	err = err ?: bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0, 0);
 
 	/* Ensure the data we read matches the data we wrote */
 	for (i = 0; i < sizeof(read_data); i++) {
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next v1] bpf: Add flags arg to bpf_dynptr_read and bpf_dynptr_write APIs
  2022-07-06 23:25 [PATCH bpf-next v1] bpf: Add flags arg to bpf_dynptr_read and bpf_dynptr_write APIs Joanne Koong
@ 2022-07-07 19:52 ` Alexei Starovoitov
  2022-07-08  0:20 ` patchwork-bot+netdevbpf
  1 sibling, 0 replies; 3+ messages in thread
From: Alexei Starovoitov @ 2022-07-07 19:52 UTC (permalink / raw)
  To: Joanne Koong; +Cc: bpf, Andrii Nakryiko, Daniel Borkmann, Alexei Starovoitov

On Wed, Jul 6, 2022 at 4:26 PM Joanne Koong <joannelkoong@gmail.com> wrote:
>
> Commit 13bbbfbea759 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write")
> added the bpf_dynptr_write and bpf_dynptr_read APIs.
>
> However, it will be useful for some dynptr types to pass in flags as
> well (eg when writing to a skb, the user may like to invalidate the
> hash or recompute the checksum).
>
> This patch adds a "u64 flags" arg to the bpf_dynptr_read and
> bpf_dynptr_write APIs.
>
> Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
> Fixes: 13bbbfbea759 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write")

Ouch. It's an uapi change in the released kernel :(
It has to go via bpf tree instead of bpf-next.

We have to add support for bpf_dynptr to kfunc and the verifier,
so we can use kfunc-s for all future extensions in dynptr area.

> ---
>  include/uapi/linux/bpf.h                           | 11 +++++++----
>  kernel/bpf/helpers.c                               | 12 ++++++++----
>  tools/include/uapi/linux/bpf.h                     | 11 +++++++----
>  tools/testing/selftests/bpf/progs/dynptr_fail.c    | 10 +++++-----
>  tools/testing/selftests/bpf/progs/dynptr_success.c |  4 ++--
>  5 files changed, 29 insertions(+), 19 deletions(-)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 379e68fb866f..3dd13fe738b9 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -5226,22 +5226,25 @@ union bpf_attr {
>   *     Return
>   *             Nothing. Always succeeds.
>   *
> - * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset)
> + * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset, u64 flags)

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next v1] bpf: Add flags arg to bpf_dynptr_read and bpf_dynptr_write APIs
  2022-07-06 23:25 [PATCH bpf-next v1] bpf: Add flags arg to bpf_dynptr_read and bpf_dynptr_write APIs Joanne Koong
  2022-07-07 19:52 ` Alexei Starovoitov
@ 2022-07-08  0:20 ` patchwork-bot+netdevbpf
  1 sibling, 0 replies; 3+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-07-08  0:20 UTC (permalink / raw)
  To: Joanne Koong; +Cc: bpf, andrii, daniel, ast

Hello:

This patch was applied to bpf/bpf.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Wed,  6 Jul 2022 16:25:47 -0700 you wrote:
> Commit 13bbbfbea759 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write")
> added the bpf_dynptr_write and bpf_dynptr_read APIs.
> 
> However, it will be useful for some dynptr types to pass in flags as
> well (eg when writing to a skb, the user may like to invalidate the
> hash or recompute the checksum).
> 
> [...]

Here is the summary with links:
  - [bpf-next,v1] bpf: Add flags arg to bpf_dynptr_read and bpf_dynptr_write APIs
    https://git.kernel.org/bpf/bpf/c/59018468b631

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html



^ permalink raw reply	[flat|nested] 3+ messages in thread
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2022-07-06 23:25 [PATCH bpf-next v1] bpf: Add flags arg to bpf_dynptr_read and bpf_dynptr_write APIs Joanne Koong
2022-07-07 19:52 ` Alexei Starovoitov
2022-07-08  0:20 ` patchwork-bot+netdevbpf

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