From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AFB6017744 for ; Thu, 20 Jul 2023 11:36:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77248C433C8; Thu, 20 Jul 2023 11:36:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1689853006; bh=1NOTkUkcC/ykrajtWRjvJmGqbB09eeCPIMA8M/RmldU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ejg1g1tVHbCXvZrYXfd1Jmt8Nj3aOOFc+4pCJkrfnXW+CC9pg1a8JDXew4hZFZnja /eWZOq5zjaVBuSDBTOyN/d0cioZOXMCoLSw9dAdpVlh7vjkZtCwC+eHCysSxLx/HzI VYWS4Vxb638U5Bs629Jl4uwOvP1lu5/n5Nk0qOnvoxcOBj3pT0z9oh/aKBRGImJpcv yfxCjbJ+wXNTIF6xPIkDhlWnzHqZJlhEgIBxYIRi6nlx99mptpP8sU3HjAWLq6HtXz lc9IBaYg0iB+jJpcymp2plHKU0VlWL/IhwC+7tgxLxL+KlmzFMopMjs1l+kT1KAAFe CDuzehDhCMKFQ== From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: Oleg Nesterov , bpf@vger.kernel.org, Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo Subject: [PATCHv4 bpf-next 05/28] bpf: Add pid filter support for uprobe_multi link Date: Thu, 20 Jul 2023 13:35:27 +0200 Message-ID: <20230720113550.369257-6-jolsa@kernel.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230720113550.369257-1-jolsa@kernel.org> References: <20230720113550.369257-1-jolsa@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Adding support to specify pid for uprobe_multi link and the uprobes are created only for task with given pid value. Using the consumer.filter filter callback for that, so the task gets filtered during the uprobe installation. We still need to check the task during runtime in the uprobe handler, because the handler could get executed if there's another system wide consumer on the same uprobe (thanks Oleg for the insight). Cc: Oleg Nesterov Reviewed-by: Oleg Nesterov Signed-off-by: Jiri Olsa --- include/uapi/linux/bpf.h | 1 + kernel/bpf/syscall.c | 2 +- kernel/trace/bpf_trace.c | 33 +++++++++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 1 + 4 files changed, 36 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index c6fbb0f948f4..7b6badd4c166 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1607,6 +1607,7 @@ union bpf_attr { __aligned_u64 cookies; __u32 cnt; __u32 flags; + __u32 pid; } uprobe_multi; }; } link_create; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 840b622b7db1..2bf986c86f2f 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -4832,7 +4832,7 @@ static int bpf_map_do_batch(const union bpf_attr *attr, return err; } -#define BPF_LINK_CREATE_LAST_FIELD link_create.uprobe_multi.cookies +#define BPF_LINK_CREATE_LAST_FIELD link_create.uprobe_multi.pid static int link_create(union bpf_attr *attr, bpfptr_t uattr) { struct bpf_prog *prog; diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index d73a47bd2bbd..d5f30747378a 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2998,6 +2998,7 @@ struct bpf_uprobe_multi_link { struct bpf_link link; u32 cnt; struct bpf_uprobe *uprobes; + struct task_struct *task; }; struct bpf_uprobe_multi_run_ctx { @@ -3023,6 +3024,8 @@ static void bpf_uprobe_multi_link_release(struct bpf_link *link) umulti_link = container_of(link, struct bpf_uprobe_multi_link, link); bpf_uprobe_unregister(&umulti_link->path, umulti_link->uprobes, umulti_link->cnt); + if (umulti_link->task) + put_task_struct(umulti_link->task); } static void bpf_uprobe_multi_link_dealloc(struct bpf_link *link) @@ -3054,6 +3057,9 @@ static int uprobe_prog_run(struct bpf_uprobe *uprobe, struct bpf_run_ctx *old_run_ctx; int err = 0; + if (link->task && current != link->task) + return 0; + might_fault(); migrate_disable(); @@ -3076,6 +3082,16 @@ static int uprobe_prog_run(struct bpf_uprobe *uprobe, return err; } +static bool +uprobe_multi_link_filter(struct uprobe_consumer *con, enum uprobe_filter_ctx ctx, + struct mm_struct *mm) +{ + struct bpf_uprobe *uprobe; + + uprobe = container_of(con, struct bpf_uprobe, consumer); + return uprobe->link->task->mm == mm; +} + static int uprobe_multi_link_handler(struct uprobe_consumer *con, struct pt_regs *regs) { @@ -3109,12 +3125,14 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr unsigned long *ref_ctr_offsets = NULL; struct bpf_link_primer link_primer; struct bpf_uprobe *uprobes = NULL; + struct task_struct *task = NULL; unsigned long __user *uoffsets; u64 __user *ucookies; void __user *upath; u32 flags, cnt, i; struct path path; char *name; + pid_t pid; int err; /* no support for 32bit archs yet */ @@ -3158,6 +3176,15 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr goto error_path_put; } + pid = attr->link_create.uprobe_multi.pid; + if (pid) { + rcu_read_lock(); + task = get_pid_task(find_vpid(pid), PIDTYPE_PID); + rcu_read_unlock(); + if (!task) + goto error_path_put; + } + err = -ENOMEM; link = kzalloc(sizeof(*link), GFP_KERNEL); @@ -3192,11 +3219,15 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr uprobes[i].consumer.ret_handler = uprobe_multi_link_ret_handler; else uprobes[i].consumer.handler = uprobe_multi_link_handler; + + if (pid) + uprobes[i].consumer.filter = uprobe_multi_link_filter; } link->cnt = cnt; link->uprobes = uprobes; link->path = path; + link->task = task; bpf_link_init(&link->link, BPF_LINK_TYPE_UPROBE_MULTI, &bpf_uprobe_multi_link_lops, prog); @@ -3225,6 +3256,8 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr kvfree(ref_ctr_offsets); kvfree(uprobes); kfree(link); + if (task) + put_task_struct(task); error_path_put: path_put(&path); return err; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 492072ef5029..8e163ed0be9a 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1607,6 +1607,7 @@ union bpf_attr { __aligned_u64 cookies; __u32 cnt; __u32 flags; + __u32 pid; } uprobe_multi; }; } link_create; -- 2.41.0