From: Song Liu <songliubraving@fb.com>
To: <netdev@vger.kernel.org>, <bpf@vger.kernel.org>
Cc: <ast@kernel.org>, <daniel@iogearbox.net>, <kernel-team@fb.com>,
<lmb@cloudflare.com>, <jannh@google.com>,
<gregkh@linuxfoundation.org>, Song Liu <songliubraving@fb.com>
Subject: [PATCH v2 bpf-next 3/4] libbpf: add libbpf_[enable|disable]_sys_bpf()
Date: Thu, 27 Jun 2019 13:19:22 -0700 [thread overview]
Message-ID: <20190627201923.2589391-4-songliubraving@fb.com> (raw)
In-Reply-To: <20190627201923.2589391-1-songliubraving@fb.com>
This patch adds two more API to libbpf: libbpf_enable_sys_bpf() and
libbpf_disable_sys_bpf().
For root, these two APIs are no-op.
Signed-off-by: Song Liu <songliubraving@fb.com>
---
tools/lib/bpf/libbpf.c | 54 ++++++++++++++++++++++++++++++++++++++++
tools/lib/bpf/libbpf.h | 7 ++++++
tools/lib/bpf/libbpf.map | 2 ++
3 files changed, 63 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 5186b7710430..449764840c5a 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -35,6 +35,7 @@
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/vfs.h>
+#include <sys/ioctl.h>
#include <tools/libc_compat.h>
#include <libelf.h>
#include <gelf.h>
@@ -4286,3 +4287,56 @@ int libbpf_num_possible_cpus(void)
}
return cpus;
}
+
+LIBBPF_API bool libbpf_enable_sys_bpf(void)
+{
+ char *cp, errmsg[STRERR_BUFSIZE];
+ int fd, ret;
+
+ if (geteuid() == 0)
+ return true;
+
+ fd = open(LIBBPF_DEV_BPF, O_WRONLY);
+ if (fd < 0) {
+ cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
+ pr_warning("failed to open %s: %s\n", LIBBPF_DEV_BPF, cp);
+ return false;
+ }
+
+ ret = ioctl(fd, BPF_DEV_IOCTL_ENABLE_SYS_BPF);
+
+ if (ret) {
+ cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
+ pr_warning("failed to enable access to sys_bpf(): %s\n", cp);
+ close(fd);
+ return false;
+ }
+ close(fd);
+ pr_debug("enabled access to sys_bpf() for non-privileged user\n");
+ return true;
+}
+
+LIBBPF_API void libbpf_disable_sys_bpf(void)
+{
+ char *cp, errmsg[STRERR_BUFSIZE];
+ int fd, ret;
+
+ if (geteuid() == 0)
+ return;
+
+ fd = open(LIBBPF_DEV_BPF, O_WRONLY);
+ if (fd < 0) {
+ cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
+ pr_warning("failed to open %s: %s\n", LIBBPF_DEV_BPF, cp);
+ return;
+ }
+
+ ret = ioctl(fd, BPF_DEV_IOCTL_DISABLE_SYS_BPF);
+ if (ret) {
+ cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
+ pr_warning("failed to disable access to sys_bpf(): %s\n", cp);
+ close(fd);
+ }
+ close(fd);
+ pr_debug("disabled access to sys_bpf() for non-privileged user\n");
+}
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index d639f47e3110..0e3b9c0f1cdf 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -470,6 +470,13 @@ bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear);
*/
LIBBPF_API int libbpf_num_possible_cpus(void);
+#define LIBBPF_DEV_BPF "/dev/bpf"
+
+/* (For non-root user) get permission to access bpf() syscall */
+LIBBPF_API bool libbpf_enable_sys_bpf(void);
+/* (For non-root user) put permission to access bpf() syscall */
+LIBBPF_API void libbpf_disable_sys_bpf(void);
+
#ifdef __cplusplus
} /* extern "C" */
#endif
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 2c6d835620d2..c5951315a3a5 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -173,4 +173,6 @@ LIBBPF_0.0.4 {
btf__parse_elf;
bpf_object__load_xattr;
libbpf_num_possible_cpus;
+ libbpf_enable_sys_bpf;
+ libbpf_disable_sys_bpf;
} LIBBPF_0.0.3;
--
2.17.1
next prev parent reply other threads:[~2019-06-27 20:19 UTC|newest]
Thread overview: 92+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-27 20:19 [PATCH v2 bpf-next 0/4] sys_bpf() access control via /dev/bpf Song Liu
2019-06-27 20:19 ` [PATCH v2 bpf-next 1/4] bpf: unprivileged BPF access " Song Liu
2019-06-27 23:40 ` Andy Lutomirski
2019-06-27 23:42 ` Andy Lutomirski
2019-06-28 10:28 ` Christian Brauner
2019-06-28 9:05 ` Lorenz Bauer
2019-06-28 19:04 ` Song Liu
2019-06-30 0:12 ` Andy Lutomirski
2019-07-01 9:03 ` Song Liu
2019-07-02 1:59 ` Andy Lutomirski
2019-07-02 18:24 ` Kees Cook
2019-07-02 21:32 ` Andy Lutomirski
2019-07-02 23:48 ` Song Liu
2019-07-22 20:53 ` Song Liu
2019-07-23 10:45 ` Lorenz Bauer
2019-07-23 15:11 ` Andy Lutomirski
2019-07-23 22:56 ` Song Liu
2019-07-24 1:40 ` Andy Lutomirski
2019-07-24 6:30 ` Song Liu
2019-07-27 18:20 ` Song Liu
2019-07-30 5:07 ` Song Liu
2019-07-30 20:24 ` Andy Lutomirski
2019-07-31 8:10 ` Song Liu
2019-07-31 19:09 ` Andy Lutomirski
2019-08-02 7:21 ` Song Liu
2019-08-04 22:16 ` Andy Lutomirski
2019-08-05 0:08 ` Andy Lutomirski
2019-08-05 5:47 ` Andy Lutomirski
2019-08-05 7:36 ` Song Liu
2019-08-05 17:23 ` Andy Lutomirski
2019-08-05 19:21 ` Alexei Starovoitov
2019-08-05 21:25 ` Andy Lutomirski
2019-08-05 22:21 ` Andy Lutomirski
2019-08-06 1:11 ` Alexei Starovoitov
2019-08-07 5:24 ` Andy Lutomirski
2019-08-07 9:03 ` Lorenz Bauer
2019-08-07 13:52 ` Andy Lutomirski
2019-08-13 21:58 ` Alexei Starovoitov
2019-08-13 22:26 ` Daniel Colascione
2019-08-13 23:24 ` Andy Lutomirski
2019-08-13 23:06 ` Andy Lutomirski
2019-08-14 0:57 ` Alexei Starovoitov
2019-08-14 17:51 ` Andy Lutomirski
2019-08-14 22:05 ` Alexei Starovoitov
2019-08-14 22:30 ` Andy Lutomirski
2019-08-14 23:33 ` Alexei Starovoitov
2019-08-14 23:59 ` Andy Lutomirski
2019-08-15 0:36 ` Alexei Starovoitov
2019-08-15 11:24 ` Jordan Glover
2019-08-15 17:28 ` Alexei Starovoitov
2019-08-15 18:36 ` Andy Lutomirski
2019-08-15 23:08 ` Alexei Starovoitov
2019-08-16 9:34 ` Jordan Glover
2019-08-16 9:59 ` Thomas Gleixner
2019-08-16 11:33 ` Jordan Glover
2019-08-16 19:52 ` Alexei Starovoitov
2019-08-16 20:28 ` Thomas Gleixner
2019-08-17 15:02 ` Alexei Starovoitov
2019-08-17 15:44 ` Andy Lutomirski
2019-08-19 9:15 ` Thomas Gleixner
2019-08-19 17:27 ` Alexei Starovoitov
2019-08-19 17:38 ` Andy Lutomirski
2019-08-15 18:43 ` Jordan Glover
2019-08-15 19:46 ` Kees Cook
2019-08-15 23:46 ` Alexei Starovoitov
2019-08-16 0:54 ` Andy Lutomirski
2019-08-16 5:56 ` Song Liu
2019-08-16 21:45 ` Alexei Starovoitov
2019-08-16 22:22 ` Christian Brauner
2019-08-17 15:08 ` Alexei Starovoitov
2019-08-17 15:16 ` Christian Brauner
2019-08-17 15:36 ` Alexei Starovoitov
2019-08-17 15:42 ` Christian Brauner
2019-08-22 14:17 ` Daniel Borkmann
2019-08-22 15:16 ` Andy Lutomirski
2019-08-22 15:17 ` RFC: very rough draft of a bpf permission model Andy Lutomirski
2019-08-22 23:26 ` Alexei Starovoitov
2019-08-23 23:09 ` Andy Lutomirski
2019-08-26 22:36 ` Alexei Starovoitov
2019-08-27 0:05 ` Andy Lutomirski
2019-08-27 0:34 ` Alexei Starovoitov
2019-08-22 22:48 ` [PATCH v2 bpf-next 1/4] bpf: unprivileged BPF access via /dev/bpf Alexei Starovoitov
2019-07-30 20:20 ` Andy Lutomirski
2019-07-31 7:44 ` Song Liu
2019-06-28 9:01 ` Lorenz Bauer
2019-06-28 19:10 ` Song Liu
2019-07-01 9:34 ` Lorenz Bauer
2019-07-02 19:22 ` Andrii Nakryiko
2019-07-03 7:28 ` Greg KH
2019-06-27 20:19 ` [PATCH v2 bpf-next 2/4] bpf: sync tools/include/uapi/linux/bpf.h Song Liu
2019-06-27 20:19 ` Song Liu [this message]
2019-06-27 20:19 ` [PATCH v2 bpf-next 4/4] bpftool: use libbpf_[enable|disable]_sys_bpf() Song Liu
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