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@xxxxxxxxx>
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
