From: Yafang Shao <laoar.shao@gmail.com>
To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com,
andrii@kernel.org, martin.lau@linux.dev, song@kernel.org,
yhs@fb.com, kpsingh@kernel.org, sdf@google.com,
haoluo@google.com, jolsa@kernel.org, quentin@isovalent.com,
rostedt@goodmis.org, mhiramat@kernel.org
Cc: bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
Yafang Shao <laoar.shao@gmail.com>
Subject: [PATCH v5 bpf-next 01/11] bpf: Support ->fill_link_info for kprobe_multi
Date: Fri, 23 Jun 2023 14:15:36 +0000 [thread overview]
Message-ID: <20230623141546.3751-2-laoar.shao@gmail.com> (raw)
In-Reply-To: <20230623141546.3751-1-laoar.shao@gmail.com>
With the addition of support for fill_link_info to the kprobe_multi link,
users will gain the ability to inspect it conveniently using the
`bpftool link show`. This enhancement provides valuable information to the
user, including the count of probed functions and their respective
addresses. It's important to note that if the kptr_restrict setting is not
permitted, the probed address will not be exposed, ensuring security.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
include/uapi/linux/bpf.h | 5 +++++
kernel/trace/bpf_trace.c | 28 ++++++++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 5 +++++
3 files changed, 38 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index a7b5e91..23691ea 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -6438,6 +6438,11 @@ struct bpf_link_info {
__s32 priority;
__u32 flags;
} netfilter;
+ struct {
+ __aligned_u64 addrs; /* in/out: addresses buffer ptr */
+ __u32 count;
+ __u32 flags;
+ } kprobe_multi;
};
} __attribute__((aligned(8)));
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 2bc41e6..2123197b 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2459,6 +2459,7 @@ struct bpf_kprobe_multi_link {
u32 cnt;
u32 mods_cnt;
struct module **mods;
+ u32 flags;
};
struct bpf_kprobe_multi_run_ctx {
@@ -2548,9 +2549,35 @@ static void bpf_kprobe_multi_link_dealloc(struct bpf_link *link)
kfree(kmulti_link);
}
+static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link,
+ struct bpf_link_info *info)
+{
+ u64 __user *uaddrs = u64_to_user_ptr(info->kprobe_multi.addrs);
+ struct bpf_kprobe_multi_link *kmulti_link;
+ u32 ucount = info->kprobe_multi.count;
+
+ if (!uaddrs ^ !ucount)
+ return -EINVAL;
+
+ kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link);
+ info->kprobe_multi.count = kmulti_link->cnt;
+ info->kprobe_multi.flags = kmulti_link->flags;
+
+ if (!uaddrs)
+ return 0;
+ if (ucount < kmulti_link->cnt)
+ return -EINVAL;
+ if (!kallsyms_show_value(current_cred()))
+ return 0;
+ if (copy_to_user(uaddrs, kmulti_link->addrs, ucount * sizeof(u64)))
+ return -EFAULT;
+ return 0;
+}
+
static const struct bpf_link_ops bpf_kprobe_multi_link_lops = {
.release = bpf_kprobe_multi_link_release,
.dealloc = bpf_kprobe_multi_link_dealloc,
+ .fill_link_info = bpf_kprobe_multi_link_fill_link_info,
};
static void bpf_kprobe_multi_cookie_swap(void *a, void *b, int size, const void *priv)
@@ -2862,6 +2889,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
link->addrs = addrs;
link->cookies = cookies;
link->cnt = cnt;
+ link->flags = flags;
if (cookies) {
/*
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index a7b5e91..23691ea 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -6438,6 +6438,11 @@ struct bpf_link_info {
__s32 priority;
__u32 flags;
} netfilter;
+ struct {
+ __aligned_u64 addrs; /* in/out: addresses buffer ptr */
+ __u32 count;
+ __u32 flags;
+ } kprobe_multi;
};
} __attribute__((aligned(8)));
--
1.8.3.1
next prev parent reply other threads:[~2023-06-23 14:16 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-23 14:15 [PATCH v5 bpf-next 00/11] bpf: Support ->fill_link_info for kprobe_multi and perf_event links Yafang Shao
2023-06-23 14:15 ` Yafang Shao [this message]
2023-06-23 21:45 ` [PATCH v5 bpf-next 01/11] bpf: Support ->fill_link_info for kprobe_multi Andrii Nakryiko
2023-06-25 14:34 ` Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 02/11] bpftool: Dump the kernel symbol's module name Yafang Shao
2023-06-23 16:48 ` Quentin Monnet
2023-06-23 14:15 ` [PATCH v5 bpf-next 03/11] bpftool: Show kprobe_multi link info Yafang Shao
2023-06-23 16:48 ` Quentin Monnet
2023-06-25 14:29 ` Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 04/11] bpf: Protect probed address based on kptr_restrict setting Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 05/11] bpf: Clear the probe_addr for uprobe Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 06/11] bpf: Expose symbol's respective address Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 07/11] bpf: Add a common helper bpf_copy_to_user() Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 08/11] bpf: Add bpf_perf_link_fill_common() Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 09/11] bpf: Support ->fill_link_info for perf_event Yafang Shao
2023-06-23 21:55 ` Andrii Nakryiko
2023-06-25 14:35 ` Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 10/11] bpftool: Add perf event names Yafang Shao
2023-06-23 16:49 ` Quentin Monnet
2023-06-25 14:30 ` Yafang Shao
2023-06-23 14:15 ` [PATCH v5 bpf-next 11/11] bpftool: Show perf link info Yafang Shao
2023-06-23 16:49 ` Quentin Monnet
2023-06-25 14:31 ` Yafang Shao
2023-06-23 17:13 ` Alexei Starovoitov
2023-06-25 14:32 ` Yafang Shao
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