Similarly to bpf_copy_from_user(), also allow sleepable BPF programs
to write to user memory.
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
include/linux/bpf.h | 1 +
include/uapi/linux/bpf.h | 8 ++++++++
kernel/bpf/helpers.c | 17 +++++++++++++++++
tools/include/uapi/linux/bpf.h | 7 +++++++
4 files changed, 33 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 00597b0c719c..9b775e2b2a01 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1899,6 +1899,7 @@ extern const struct bpf_func_proto bpf_skc_to_tcp_timewait_sock_proto;
extern const struct bpf_func_proto bpf_skc_to_tcp_request_sock_proto;
extern const struct bpf_func_proto bpf_skc_to_udp6_sock_proto;
extern const struct bpf_func_proto bpf_copy_from_user_proto;
+extern const struct bpf_func_proto bpf_copy_to_user_proto;
extern const struct bpf_func_proto bpf_snprintf_btf_proto;
extern const struct bpf_func_proto bpf_per_cpu_ptr_proto;
extern const struct bpf_func_proto bpf_this_cpu_ptr_proto;
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 7719ec4a33e7..6f19839d2b05 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3648,6 +3648,13 @@ union bpf_attr {
* Return
* 0 on success, or a negative error in case of failure.
*
+ * long bpf_copy_to_user(void *user_ptr, const void *src, u32 size)
+ * Description
+ * Read *size* bytes from *src* and store the data in user space
+ * address *user_ptr*. This is a wrapper of **copy_to_user**\ ().
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
* long bpf_snprintf_btf(char *str, u32 str_size, struct btf_ptr *ptr, u32 btf_ptr_size, u64 flags)
* Description
* Use BTF to store a string representation of *ptr*->ptr in *str*,
@@ -4085,6 +4092,7 @@ union bpf_attr {
FN(iouring_queue_sqe), \
FN(iouring_emit_cqe), \
FN(iouring_reap_cqe), \
+ FN(copy_to_user), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 308427fe03a3..9d7814c564e5 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -634,6 +634,23 @@ const struct bpf_func_proto bpf_copy_from_user_proto = {
.arg3_type = ARG_ANYTHING,
};
+BPF_CALL_3(bpf_copy_to_user, void __user *, user_ptr,
+ const void *, src, u32, size)
+{
+ int ret = copy_to_user(user_ptr, src, size);
+
+ return ret ? -EFAULT : 0;
+}
+
+const struct bpf_func_proto bpf_copy_to_user_proto = {
+ .func = bpf_copy_to_user,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_ANYTHING,
+ .arg2_type = ARG_PTR_TO_MEM,
+ .arg3_type = ARG_CONST_SIZE_OR_ZERO,
+};
+
BPF_CALL_2(bpf_per_cpu_ptr, const void *, ptr, u32, cpu)
{
if (cpu >= nr_cpu_ids)
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 79c893310492..18d497247d69 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3647,6 +3647,13 @@ union bpf_attr {
* Return
* 0 on success, or a negative error in case of failure.
*
+ * long bpf_copy_to_user(void *user_ptr, const void *src, u32 size)
+ * Description
+ * Read *size* bytes from *src* and store the data in user space
+ * address *user_ptr*. This is a wrapper of **copy_to_user**\ ().
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
* long bpf_snprintf_btf(char *str, u32 str_size, struct btf_ptr *ptr, u32 btf_ptr_size, u64 flags)
* Description
* Use BTF to store a string representation of *ptr*->ptr in *str*,
--
2.31.1
