bpf: Add bpf_dynptr_read and bpf_dynptr_write (13bbbfbe) · Commits · EulixOS / Software / Kernel

include/uapi/linux/bpf.h

+19 −0

Original line number	Diff line number	Diff line
		@@ -5221,6 +5221,23 @@ union bpf_attr {
		* 'bpf_ringbuf_discard'.
		* Return
		* Nothing. Always succeeds.
		*
		* long bpf_dynptr_read(void dst, u32 len, struct bpf_dynptr src, u32 offset)
		* Description
		* Read len bytes from src into dst, starting from offset
		* into src.
		* Return
		* 0 on success, -E2BIG if offset + len exceeds the length
		* of src's data, -EINVAL if src is an invalid dynptr.
		*
		* long bpf_dynptr_write(struct bpf_dynptr dst, u32 offset, void src, u32 len)
		* Description
		* Write len bytes from src into dst, starting from offset
		* into dst.
		* 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.
		*/
		#define __BPF_FUNC_MAPPER(FN) \
		FN(unspec), \
		@@ -5424,6 +5441,8 @@ union bpf_attr {
		FN(ringbuf_reserve_dynptr), \
		FN(ringbuf_submit_dynptr), \
		FN(ringbuf_discard_dynptr), \
		FN(dynptr_read), \
		FN(dynptr_write), \
		/* */

		/* integer value in 'imm' field of BPF_CALL instruction selects which helper

kernel/bpf/helpers.c

+78 −0

Original line number	Diff line number	Diff line
		@@ -1417,12 +1417,24 @@ const struct bpf_func_proto bpf_kptr_xchg_proto = {
		*/
		#define DYNPTR_MAX_SIZE ((1UL << 24) - 1)
		#define DYNPTR_TYPE_SHIFT 28
		#define DYNPTR_SIZE_MASK 0xFFFFFF
		#define DYNPTR_RDONLY_BIT BIT(31)

		static bool bpf_dynptr_is_rdonly(struct bpf_dynptr_kern *ptr)
		{
		return ptr->size & DYNPTR_RDONLY_BIT;
		}

		static void bpf_dynptr_set_type(struct bpf_dynptr_kern *ptr, enum bpf_dynptr_type type)
		{
		ptr->size \|= type << DYNPTR_TYPE_SHIFT;
		}

		static u32 bpf_dynptr_get_size(struct bpf_dynptr_kern *ptr)
		{
		return ptr->size & DYNPTR_SIZE_MASK;
		}

		int bpf_dynptr_check_size(u32 size)
		{
		return size > DYNPTR_MAX_SIZE ? -E2BIG : 0;
		@@ -1442,6 +1454,16 @@ void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr)
		memset(ptr, 0, sizeof(*ptr));
		}

		static int bpf_dynptr_check_off_len(struct bpf_dynptr_kern *ptr, u32 offset, u32 len)
		{
		u32 size = bpf_dynptr_get_size(ptr);

		if (len > size \|\| offset > size - len)
		return -E2BIG;

		return 0;
		}

		BPF_CALL_4(bpf_dynptr_from_mem, void , data, u32, size, u64, flags, struct bpf_dynptr_kern , ptr)
		{
		int err;
		@@ -1475,6 +1497,58 @@ 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)
		{
		int err;

		if (!src->data)
		return -EINVAL;

		err = bpf_dynptr_check_off_len(src, offset, len);
		if (err)
		return err;

		memcpy(dst, src->data + src->offset + offset, len);

		return 0;
		}

		const struct bpf_func_proto bpf_dynptr_read_proto = {
		.func = bpf_dynptr_read,
		.gpl_only = false,
		.ret_type = RET_INTEGER,
		.arg1_type = ARG_PTR_TO_UNINIT_MEM,
		.arg2_type = ARG_CONST_SIZE_OR_ZERO,
		.arg3_type = ARG_PTR_TO_DYNPTR,
		.arg4_type = ARG_ANYTHING,
		};

		BPF_CALL_4(bpf_dynptr_write, struct bpf_dynptr_kern , dst, u32, offset, void , src, u32, len)
		{
		int err;

		if (!dst->data \|\| bpf_dynptr_is_rdonly(dst))
		return -EINVAL;

		err = bpf_dynptr_check_off_len(dst, offset, len);
		if (err)
		return err;

		memcpy(dst->data + dst->offset + offset, src, len);

		return 0;
		}

		const struct bpf_func_proto bpf_dynptr_write_proto = {
		.func = bpf_dynptr_write,
		.gpl_only = false,
		.ret_type = RET_INTEGER,
		.arg1_type = ARG_PTR_TO_DYNPTR,
		.arg2_type = ARG_ANYTHING,
		.arg3_type = ARG_PTR_TO_MEM \| MEM_RDONLY,
		.arg4_type = ARG_CONST_SIZE_OR_ZERO,
		};

		const struct bpf_func_proto bpf_get_current_task_proto __weak;
		const struct bpf_func_proto bpf_get_current_task_btf_proto __weak;
		const struct bpf_func_proto bpf_probe_read_user_proto __weak;
		@@ -1537,6 +1611,10 @@ bpf_base_func_proto(enum bpf_func_id func_id)
		return &bpf_strncmp_proto;
		case BPF_FUNC_dynptr_from_mem:
		return &bpf_dynptr_from_mem_proto;
		case BPF_FUNC_dynptr_read:
		return &bpf_dynptr_read_proto;
		case BPF_FUNC_dynptr_write:
		return &bpf_dynptr_write_proto;
		default:
		break;
		}

tools/include/uapi/linux/bpf.h

+19 −0

Original line number	Diff line number	Diff line
		@@ -5221,6 +5221,23 @@ union bpf_attr {
		* 'bpf_ringbuf_discard'.
		* Return
		* Nothing. Always succeeds.
		*
		* long bpf_dynptr_read(void dst, u32 len, struct bpf_dynptr src, u32 offset)
		* Description
		* Read len bytes from src into dst, starting from offset
		* into src.
		* Return
		* 0 on success, -E2BIG if offset + len exceeds the length
		* of src's data, -EINVAL if src is an invalid dynptr.
		*
		* long bpf_dynptr_write(struct bpf_dynptr dst, u32 offset, void src, u32 len)
		* Description
		* Write len bytes from src into dst, starting from offset
		* into dst.
		* 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.
		*/
		#define __BPF_FUNC_MAPPER(FN) \
		FN(unspec), \
		@@ -5424,6 +5441,8 @@ union bpf_attr {
		FN(ringbuf_reserve_dynptr), \
		FN(ringbuf_submit_dynptr), \
		FN(ringbuf_discard_dynptr), \
		FN(dynptr_read), \
		FN(dynptr_write), \
		/* */

		/* integer value in 'imm' field of BPF_CALL instruction selects which helper