From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: davem@davemloft.net
Cc: daniel@iogearbox.net, paulmck@kernel.org, netdev@vger.kernel.org,
bpf@vger.kernel.org, kernel-team@fb.com
Subject: [PATCH RFC v3 bpf-next 2/4] bpf: Add bpf_copy_from_user() helper.
Date: Thu, 11 Jun 2020 15:23:38 -0700 [thread overview]
Message-ID: <20200611222340.24081-3-alexei.starovoitov@gmail.com> (raw)
In-Reply-To: <20200611222340.24081-1-alexei.starovoitov@gmail.com>
From: Alexei Starovoitov <ast@kernel.org>
Sleepable BPF programs can now use copy_from_user() to access user memory.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
include/linux/bpf.h | 1 +
include/uapi/linux/bpf.h | 11 ++++++++++-
kernel/bpf/helpers.c | 22 ++++++++++++++++++++++
kernel/trace/bpf_trace.c | 2 ++
tools/include/uapi/linux/bpf.h | 11 ++++++++++-
5 files changed, 45 insertions(+), 2 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 6819000682a5..c8c9217f3ac9 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1632,6 +1632,7 @@ extern const struct bpf_func_proto bpf_ringbuf_reserve_proto;
extern const struct bpf_func_proto bpf_ringbuf_submit_proto;
extern const struct bpf_func_proto bpf_ringbuf_discard_proto;
extern const struct bpf_func_proto bpf_ringbuf_query_proto;
+extern const struct bpf_func_proto bpf_copy_from_user_proto;
const struct bpf_func_proto *bpf_tracing_func_proto(
enum bpf_func_id func_id, const struct bpf_prog *prog);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 0bef454c9598..a38c806d34ad 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3260,6 +3260,13 @@ union bpf_attr {
* case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level
* is returned or the error code -EACCES in case the skb is not
* subject to CHECKSUM_UNNECESSARY.
+ *
+ * int bpf_copy_from_user(void *dst, u32 size, const void *user_ptr)
+ * Description
+ * Read *size* bytes from user space address *user_ptr* and store
+ * the data in *dst*. This is a wrapper of copy_from_user().
+ * Return
+ * 0 on success, or a negative error in case of failure.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -3397,7 +3404,9 @@ union bpf_attr {
FN(ringbuf_submit), \
FN(ringbuf_discard), \
FN(ringbuf_query), \
- FN(csum_level),
+ FN(csum_level), \
+ FN(copy_from_user), \
+ /* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index be43ab3e619f..5cc7425ee476 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -601,6 +601,28 @@ const struct bpf_func_proto bpf_event_output_data_proto = {
.arg5_type = ARG_CONST_SIZE_OR_ZERO,
};
+BPF_CALL_3(bpf_copy_from_user, void *, dst, u32, size,
+ const void __user *, user_ptr)
+{
+ int ret = copy_from_user(dst, user_ptr, size);
+
+ if (unlikely(ret)) {
+ memset(dst, 0, size);
+ ret = -EFAULT;
+ }
+
+ return ret;
+}
+
+const struct bpf_func_proto bpf_copy_from_user_proto = {
+ .func = bpf_copy_from_user,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_UNINIT_MEM,
+ .arg2_type = ARG_CONST_SIZE_OR_ZERO,
+ .arg3_type = ARG_ANYTHING,
+};
+
const struct bpf_func_proto bpf_get_current_task_proto __weak;
const struct bpf_func_proto bpf_probe_read_user_proto __weak;
const struct bpf_func_proto bpf_probe_read_user_str_proto __weak;
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 3744372a24e2..c1e833000fc3 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1098,6 +1098,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_ringbuf_discard_proto;
case BPF_FUNC_ringbuf_query:
return &bpf_ringbuf_query_proto;
+ case BPF_FUNC_copy_from_user:
+ return prog->aux->sleepable ? &bpf_copy_from_user_proto : NULL;
default:
return NULL;
}
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 0bef454c9598..a38c806d34ad 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3260,6 +3260,13 @@ union bpf_attr {
* case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level
* is returned or the error code -EACCES in case the skb is not
* subject to CHECKSUM_UNNECESSARY.
+ *
+ * int bpf_copy_from_user(void *dst, u32 size, const void *user_ptr)
+ * Description
+ * Read *size* bytes from user space address *user_ptr* and store
+ * the data in *dst*. This is a wrapper of copy_from_user().
+ * Return
+ * 0 on success, or a negative error in case of failure.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -3397,7 +3404,9 @@ union bpf_attr {
FN(ringbuf_submit), \
FN(ringbuf_discard), \
FN(ringbuf_query), \
- FN(csum_level),
+ FN(csum_level), \
+ FN(copy_from_user), \
+ /* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
--
2.23.0
next prev parent reply other threads:[~2020-06-11 22:23 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-11 22:23 [PATCH RFC v3 bpf-next 0/4] bpf: Introduce minimal support for sleepable progs Alexei Starovoitov
2020-06-11 22:23 ` [PATCH RFC v3 bpf-next 1/4] bpf: Introduce sleepable BPF programs Alexei Starovoitov
2020-06-11 22:29 ` Alexei Starovoitov
2020-06-12 0:04 ` Paul E. McKenney
2020-06-12 2:13 ` Alexei Starovoitov
2020-06-12 3:40 ` Paul E. McKenney
2020-06-11 22:23 ` Alexei Starovoitov [this message]
2020-06-18 22:33 ` [PATCH RFC v3 bpf-next 2/4] bpf: Add bpf_copy_from_user() helper Andrii Nakryiko
2020-06-30 0:28 ` Alexei Starovoitov
2020-06-30 18:23 ` Andrii Nakryiko
2020-06-30 18:53 ` Alexei Starovoitov
2020-06-11 22:23 ` [PATCH RFC v3 bpf-next 3/4] libbpf: support sleepable progs Alexei Starovoitov
2020-06-18 22:34 ` Andrii Nakryiko
2020-06-11 22:23 ` [PATCH RFC v3 bpf-next 4/4] selftests/bpf: basic sleepable tests Alexei Starovoitov
2020-06-18 22:43 ` Andrii Nakryiko
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