Currently, the sock_from_file prototype takes an "err" pointer that is
either not set or set to -ENOTSOCK IFF the returned socket is NULL. This
makes the error redundant and it is ignored by a few callers.
This patch simplifies the API by letting callers deduce the error based
on whether the returned socket is NULL or not.
Suggested-by: Al Viro <[email protected]>
Signed-off-by: Florent Revest <[email protected]>
Reviewed-by: KP Singh <[email protected]>
---
fs/eventpoll.c | 3 +--
fs/io_uring.c | 16 ++++++++--------
include/linux/net.h | 2 +-
net/core/netclassid_cgroup.c | 3 +--
net/core/netprio_cgroup.c | 3 +--
net/core/sock.c | 8 +-------
net/socket.c | 27 ++++++++++++++++-----------
7 files changed, 29 insertions(+), 33 deletions(-)
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 73c346e503d7..19499b7bb82c 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -416,12 +416,11 @@ static inline void ep_set_busy_poll_napi_id(struct epitem *epi)
unsigned int napi_id;
struct socket *sock;
struct sock *sk;
- int err;
if (!net_busy_loop_on())
return;
- sock = sock_from_file(epi->ffd.file, &err);
+ sock = sock_from_file(epi->ffd.file);
if (!sock)
return;
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 8018c7076b25..ace99b15cbd3 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4341,9 +4341,9 @@ static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
unsigned flags;
int ret;
- sock = sock_from_file(req->file, &ret);
+ sock = sock_from_file(req->file);
if (unlikely(!sock))
- return ret;
+ return -ENOTSOCK;
if (req->async_data) {
kmsg = req->async_data;
@@ -4390,9 +4390,9 @@ static int io_send(struct io_kiocb *req, bool force_nonblock,
unsigned flags;
int ret;
- sock = sock_from_file(req->file, &ret);
+ sock = sock_from_file(req->file);
if (unlikely(!sock))
- return ret;
+ return -ENOTSOCK;
ret = import_single_range(WRITE, sr->buf, sr->len, &iov, &msg.msg_iter);
if (unlikely(ret))
@@ -4569,9 +4569,9 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
unsigned flags;
int ret, cflags = 0;
- sock = sock_from_file(req->file, &ret);
+ sock = sock_from_file(req->file);
if (unlikely(!sock))
- return ret;
+ return -ENOTSOCK;
if (req->async_data) {
kmsg = req->async_data;
@@ -4632,9 +4632,9 @@ static int io_recv(struct io_kiocb *req, bool force_nonblock,
unsigned flags;
int ret, cflags = 0;
- sock = sock_from_file(req->file, &ret);
+ sock = sock_from_file(req->file);
if (unlikely(!sock))
- return ret;
+ return -ENOTSOCK;
if (req->flags & REQ_F_BUFFER_SELECT) {
kbuf = io_recv_buffer_select(req, !force_nonblock);
diff --git a/include/linux/net.h b/include/linux/net.h
index 0dcd51feef02..9e2324efc26a 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -240,7 +240,7 @@ int sock_sendmsg(struct socket *sock, struct msghdr *msg);
int sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags);
struct file *sock_alloc_file(struct socket *sock, int flags, const char *dname);
struct socket *sockfd_lookup(int fd, int *err);
-struct socket *sock_from_file(struct file *file, int *err);
+struct socket *sock_from_file(struct file *file);
#define sockfd_put(sock) fput(sock->file)
int net_ratelimit(void);
diff --git a/net/core/netclassid_cgroup.c b/net/core/netclassid_cgroup.c
index 41b24cd31562..b49c57d35a88 100644
--- a/net/core/netclassid_cgroup.c
+++ b/net/core/netclassid_cgroup.c
@@ -68,9 +68,8 @@ struct update_classid_context {
static int update_classid_sock(const void *v, struct file *file, unsigned n)
{
- int err;
struct update_classid_context *ctx = (void *)v;
- struct socket *sock = sock_from_file(file, &err);
+ struct socket *sock = sock_from_file(file);
if (sock) {
spin_lock(&cgroup_sk_update_lock);
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index 9bd4cab7d510..99a431c56f23 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -220,8 +220,7 @@ static ssize_t write_priomap(struct kernfs_open_file *of,
static int update_netprio(const void *v, struct file *file, unsigned n)
{
- int err;
- struct socket *sock = sock_from_file(file, &err);
+ struct socket *sock = sock_from_file(file);
if (sock) {
spin_lock(&cgroup_sk_update_lock);
sock_cgroup_set_prioidx(&sock->sk->sk_cgrp_data,
diff --git a/net/core/sock.c b/net/core/sock.c
index d422a6808405..eb55cf79bb24 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2827,14 +2827,8 @@ EXPORT_SYMBOL(sock_no_mmap);
void __receive_sock(struct file *file)
{
struct socket *sock;
- int error;
- /*
- * The resulting value of "error" is ignored here since we only
- * need to take action when the file is a socket and testing
- * "sock" for NULL is sufficient.
- */
- sock = sock_from_file(file, &error);
+ sock = sock_from_file(file);
if (sock) {
sock_update_netprioidx(&sock->sk->sk_cgrp_data);
sock_update_classid(&sock->sk->sk_cgrp_data);
diff --git a/net/socket.c b/net/socket.c
index 6e6cccc2104f..c799d9652a2c 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -445,17 +445,15 @@ static int sock_map_fd(struct socket *sock, int flags)
/**
* sock_from_file - Return the &socket bounded to @file.
* @file: file
- * @err: pointer to an error code return
*
- * On failure returns %NULL and assigns -ENOTSOCK to @err.
+ * On failure returns %NULL.
*/
-struct socket *sock_from_file(struct file *file, int *err)
+struct socket *sock_from_file(struct file *file)
{
if (file->f_op == &socket_file_ops)
return file->private_data; /* set in sock_map_fd */
- *err = -ENOTSOCK;
return NULL;
}
EXPORT_SYMBOL(sock_from_file);
@@ -484,9 +482,11 @@ struct socket *sockfd_lookup(int fd, int *err)
return NULL;
}
- sock = sock_from_file(file, err);
- if (!sock)
+ sock = sock_from_file(file);
+ if (!sock) {
+ *err = -ENOTSOCK;
fput(file);
+ }
return sock;
}
EXPORT_SYMBOL(sockfd_lookup);
@@ -498,11 +498,12 @@ static struct socket *sockfd_lookup_light(int fd, int *err, int *fput_needed)
*err = -EBADF;
if (f.file) {
- sock = sock_from_file(f.file, err);
+ sock = sock_from_file(f.file);
if (likely(sock)) {
*fput_needed = f.flags & FDPUT_FPUT;
return sock;
}
+ *err = -ENOTSOCK;
fdput(f);
}
return NULL;
@@ -1715,9 +1716,11 @@ int __sys_accept4_file(struct file *file, unsigned file_flags,
if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))
flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
- sock = sock_from_file(file, &err);
- if (!sock)
+ sock = sock_from_file(file);
+ if (!sock) {
+ err = -ENOTSOCK;
goto out;
+ }
err = -ENFILE;
newsock = sock_alloc();
@@ -1840,9 +1843,11 @@ int __sys_connect_file(struct file *file, struct sockaddr_storage *address,
struct socket *sock;
int err;
- sock = sock_from_file(file, &err);
- if (!sock)
+ sock = sock_from_file(file);
+ if (!sock) {
+ err = -ENOTSOCK;
goto out;
+ }
err =
security_socket_connect(sock, (struct sockaddr *)address, addrlen);
--
2.29.2.454.gaff20da3a2-goog
This extends the existing bpf_sk_storage_get test where a socket is
created and tagged with its creator's pid by a task_file iterator.
A TCP iterator is now also used at the end of the test to negate the
values already stored in the local storage. The test therefore expects
-getpid() to be stored in the local storage.
Signed-off-by: Florent Revest <[email protected]>
Acked-by: Yonghong Song <[email protected]>
---
.../selftests/bpf/prog_tests/bpf_iter.c | 13 +++++++++++++
.../progs/bpf_iter_bpf_sk_storage_helpers.c | 18 ++++++++++++++++++
2 files changed, 31 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
index 9336d0f18331..b8362147c9e3 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
@@ -978,6 +978,8 @@ static void test_bpf_sk_storage_delete(void)
/* This creates a socket and its local storage. It then runs a task_iter BPF
* program that replaces the existing socket local storage with the tgid of the
* only task owning a file descriptor to this socket, this process, prog_tests.
+ * It then runs a tcp socket iterator that negates the value in the existing
+ * socket local storage, the test verifies that the resulting value is -pid.
*/
static void test_bpf_sk_storage_get(void)
{
@@ -994,6 +996,10 @@ static void test_bpf_sk_storage_get(void)
if (CHECK(sock_fd < 0, "socket", "errno: %d\n", errno))
goto out;
+ err = listen(sock_fd, 1);
+ if (CHECK(err != 0, "listen", "errno: %d\n", errno))
+ goto out;
+
map_fd = bpf_map__fd(skel->maps.sk_stg_map);
err = bpf_map_update_elem(map_fd, &sock_fd, &val, BPF_NOEXIST);
@@ -1007,6 +1013,13 @@ static void test_bpf_sk_storage_get(void)
"map value wasn't set correctly (expected %d, got %d, err=%d)\n",
getpid(), val, err);
+ do_dummy_read(skel->progs.negate_socket_local_storage);
+
+ err = bpf_map_lookup_elem(map_fd, &sock_fd, &val);
+ CHECK(err || val != -getpid(), "bpf_map_lookup_elem",
+ "map value wasn't set correctly (expected %d, got %d, err=%d)\n",
+ -getpid(), val, err);
+
close_socket:
close(sock_fd);
out:
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_helpers.c b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_helpers.c
index dde53df37de8..6cecab2b32ba 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_helpers.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_sk_storage_helpers.c
@@ -45,3 +45,21 @@ int fill_socket_owner(struct bpf_iter__task_file *ctx)
return 0;
}
+
+SEC("iter/tcp")
+int negate_socket_local_storage(struct bpf_iter__tcp *ctx)
+{
+ struct sock_common *sk_common = ctx->sk_common;
+ int *sock_tgid;
+
+ if (!sk_common)
+ return 0;
+
+ sock_tgid = bpf_sk_storage_get(&sk_stg_map, sk_common, 0, 0);
+ if (!sock_tgid)
+ return 0;
+
+ *sock_tgid = -*sock_tgid;
+
+ return 0;
+}
--
2.29.2.454.gaff20da3a2-goog
While eBPF programs can check whether a file is a socket by file->f_op
== &socket_file_ops, they cannot convert the void private_data pointer
to a struct socket BTF pointer. In order to do this a new helper
wrapping sock_from_file is added.
This is useful to tracing programs but also other program types
inheriting this set of helpers such as iterators or LSM programs.
Signed-off-by: Florent Revest <[email protected]>
Acked-by: KP Singh <[email protected]>
Acked-by: Martin KaFai Lau <[email protected]>
---
include/uapi/linux/bpf.h | 9 +++++++++
kernel/trace/bpf_trace.c | 20 ++++++++++++++++++++
scripts/bpf_helpers_doc.py | 4 ++++
tools/include/uapi/linux/bpf.h | 9 +++++++++
4 files changed, 42 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c3458ec1f30a..a92b2b7d331b 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3817,6 +3817,14 @@ union bpf_attr {
* The **hash_algo** is returned on success,
* **-EOPNOTSUP** if IMA is disabled or **-EINVAL** if
* invalid arguments are passed.
+ *
+ * struct socket *bpf_sock_from_file(struct file *file)
+ * Description
+ * If the given file represents a socket, returns the associated
+ * socket.
+ * Return
+ * A pointer to a struct socket on success or NULL if the file is
+ * not a socket.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -3981,6 +3989,7 @@ union bpf_attr {
FN(bprm_opts_set), \
FN(ktime_get_coarse_ns), \
FN(ima_inode_hash), \
+ FN(sock_from_file), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index d255bc9b2bfa..d0aac9eac2d8 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1260,6 +1260,24 @@ const struct bpf_func_proto bpf_snprintf_btf_proto = {
.arg5_type = ARG_ANYTHING,
};
+BPF_CALL_1(bpf_sock_from_file, struct file *, file)
+{
+ return (unsigned long) sock_from_file(file);
+}
+
+BTF_ID_LIST(bpf_sock_from_file_btf_ids)
+BTF_ID(struct, socket)
+BTF_ID(struct, file)
+
+static const struct bpf_func_proto bpf_sock_from_file_proto = {
+ .func = bpf_sock_from_file,
+ .gpl_only = false,
+ .ret_type = RET_PTR_TO_BTF_ID_OR_NULL,
+ .ret_btf_id = &bpf_sock_from_file_btf_ids[0],
+ .arg1_type = ARG_PTR_TO_BTF_ID,
+ .arg1_btf_id = &bpf_sock_from_file_btf_ids[1],
+};
+
const struct bpf_func_proto *
bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
{
@@ -1356,6 +1374,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_per_cpu_ptr_proto;
case BPF_FUNC_bpf_this_cpu_ptr:
return &bpf_this_cpu_ptr_proto;
+ case BPF_FUNC_sock_from_file:
+ return &bpf_sock_from_file_proto;
default:
return NULL;
}
diff --git a/scripts/bpf_helpers_doc.py b/scripts/bpf_helpers_doc.py
index 8b829748d488..867ada23281c 100755
--- a/scripts/bpf_helpers_doc.py
+++ b/scripts/bpf_helpers_doc.py
@@ -437,6 +437,8 @@ class PrinterHelpers(Printer):
'struct path',
'struct btf_ptr',
'struct inode',
+ 'struct socket',
+ 'struct file',
]
known_types = {
'...',
@@ -482,6 +484,8 @@ class PrinterHelpers(Printer):
'struct path',
'struct btf_ptr',
'struct inode',
+ 'struct socket',
+ 'struct file',
}
mapped_types = {
'u8': '__u8',
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index c3458ec1f30a..a92b2b7d331b 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3817,6 +3817,14 @@ union bpf_attr {
* The **hash_algo** is returned on success,
* **-EOPNOTSUP** if IMA is disabled or **-EINVAL** if
* invalid arguments are passed.
+ *
+ * struct socket *bpf_sock_from_file(struct file *file)
+ * Description
+ * If the given file represents a socket, returns the associated
+ * socket.
+ * Return
+ * A pointer to a struct socket on success or NULL if the file is
+ * not a socket.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -3981,6 +3989,7 @@ union bpf_attr {
FN(bprm_opts_set), \
FN(ktime_get_coarse_ns), \
FN(ima_inode_hash), \
+ FN(sock_from_file), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
--
2.29.2.454.gaff20da3a2-goog
On Wed, Dec 02, 2020 at 09:55:27PM +0100, Florent Revest wrote:
> This extends the existing bpf_sk_storage_get test where a socket is
> created and tagged with its creator's pid by a task_file iterator.
>
> A TCP iterator is now also used at the end of the test to negate the
> values already stored in the local storage. The test therefore expects
> -getpid() to be stored in the local storage.
>
> Signed-off-by: Florent Revest <[email protected]>
> Acked-by: Yonghong Song <[email protected]>
> ---
> .../selftests/bpf/prog_tests/bpf_iter.c | 13 +++++++++++++
> .../progs/bpf_iter_bpf_sk_storage_helpers.c | 18 ++++++++++++++++++
> 2 files changed, 31 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> index 9336d0f18331..b8362147c9e3 100644
> --- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> @@ -978,6 +978,8 @@ static void test_bpf_sk_storage_delete(void)
> /* This creates a socket and its local storage. It then runs a task_iter BPF
> * program that replaces the existing socket local storage with the tgid of the
> * only task owning a file descriptor to this socket, this process, prog_tests.
> + * It then runs a tcp socket iterator that negates the value in the existing
> + * socket local storage, the test verifies that the resulting value is -pid.
> */
> static void test_bpf_sk_storage_get(void)
> {
> @@ -994,6 +996,10 @@ static void test_bpf_sk_storage_get(void)
> if (CHECK(sock_fd < 0, "socket", "errno: %d\n", errno))
> goto out;
>
> + err = listen(sock_fd, 1);
> + if (CHECK(err != 0, "listen", "errno: %d\n", errno))
> + goto out;
goto close_socket;
> +
> map_fd = bpf_map__fd(skel->maps.sk_stg_map);
>
> err = bpf_map_update_elem(map_fd, &sock_fd, &val, BPF_NOEXIST);
> @@ -1007,6 +1013,13 @@ static void test_bpf_sk_storage_get(void)
> "map value wasn't set correctly (expected %d, got %d, err=%d)\n",
> getpid(), val, err);
The failure of this CHECK here should "goto close_socket;" now.
Others LGTM.
Acked-by: Martin KaFai Lau <[email protected]>
>
> + do_dummy_read(skel->progs.negate_socket_local_storage);
> +
> + err = bpf_map_lookup_elem(map_fd, &sock_fd, &val);
> + CHECK(err || val != -getpid(), "bpf_map_lookup_elem",
> + "map value wasn't set correctly (expected %d, got %d, err=%d)\n",
> + -getpid(), val, err);
> +
> close_socket:
> close(sock_fd);
> out:
On Thu, 2020-12-03 at 18:05 -0800, Martin KaFai Lau wrote:
> On Wed, Dec 02, 2020 at 09:55:27PM +0100, Florent Revest wrote:
> > This extends the existing bpf_sk_storage_get test where a socket is
> > created and tagged with its creator's pid by a task_file iterator.
> >
> > A TCP iterator is now also used at the end of the test to negate
> > the
> > values already stored in the local storage. The test therefore
> > expects
> > -getpid() to be stored in the local storage.
> >
> > Signed-off-by: Florent Revest <[email protected]>
> > Acked-by: Yonghong Song <[email protected]>
> > ---
> > .../selftests/bpf/prog_tests/bpf_iter.c | 13 +++++++++++++
> > .../progs/bpf_iter_bpf_sk_storage_helpers.c | 18
> > ++++++++++++++++++
> > 2 files changed, 31 insertions(+)
> >
> > diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> > b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> > index 9336d0f18331..b8362147c9e3 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> > @@ -978,6 +978,8 @@ static void test_bpf_sk_storage_delete(void)
> > /* This creates a socket and its local storage. It then runs a
> > task_iter BPF
> > * program that replaces the existing socket local storage with
> > the tgid of the
> > * only task owning a file descriptor to this socket, this
> > process, prog_tests.
> > + * It then runs a tcp socket iterator that negates the value in
> > the existing
> > + * socket local storage, the test verifies that the resulting
> > value is -pid.
> > */
> > static void test_bpf_sk_storage_get(void)
> > {
> > @@ -994,6 +996,10 @@ static void test_bpf_sk_storage_get(void)
> > if (CHECK(sock_fd < 0, "socket", "errno: %d\n", errno))
> > goto out;
> >
> > + err = listen(sock_fd, 1);
> > + if (CHECK(err != 0, "listen", "errno: %d\n", errno))
> > + goto out;
>
> goto close_socket;
>
> > +
> > map_fd = bpf_map__fd(skel->maps.sk_stg_map);
> >
> > err = bpf_map_update_elem(map_fd, &sock_fd, &val, BPF_NOEXIST);
> > @@ -1007,6 +1013,13 @@ static void test_bpf_sk_storage_get(void)
> > "map value wasn't set correctly (expected %d, got %d,
> > err=%d)\n",
> > getpid(), val, err);
> The failure of this CHECK here should "goto close_socket;" now.
>
> Others LGTM.
>
> Acked-by: Martin KaFai Lau <[email protected]>
Ah good points, thanks! Fixed in v5 :)