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 C98649450 for ; Thu, 3 Aug 2023 07:35:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 69954C433C9; Thu, 3 Aug 2023 07:35:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1691048115; bh=iQ2mzCkWC/2WDIVIE9LYud8u+dDgItTAJ35hi07MVhg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uO38Q4ryy5vkBTZm6nk+ZJIZso2MbKjkb2mPyAiHK//Z7RWWQbbSURozfhvFY0i99 9rGruUJblo1ZPrdO1qxSMOaEWTQUtukQTuC9Z71WZSkm1rXoV4t0SFRArtiaAXDu8B 7BDCH1biqLpqrgPuEGJTyUjiTUhPRBuxTyrNkHl0az0otNFIR4U4W340wFhQ4vDJGh RcXXZYn0ZVO2At3V2mZTo9m/0AtvoqoD72q/yss4TMagzQmxAv1g6ZEtBxXk1I7cxq 8G46s4vdZpq5t9rqKQ3Q7zKKOIyQ4YoEJLh9qkOXuVi3gooM7pK1PY6ukV7uqaktJr xDdlfaDFdhWbg== 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 , Yafang Shao Subject: [PATCHv6 bpf-next 05/28] bpf: Add pid filter support for uprobe_multi link Date: Thu, 3 Aug 2023 09:33:57 +0200 Message-ID: <20230803073420.1558613-6-jolsa@kernel.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230803073420.1558613-1-jolsa@kernel.org> References: <20230803073420.1558613-1-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 2b6cd7d1c165..558902237338 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1642,6 +1642,7 @@ 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 98459fb34ff7..54df18b3fc4e 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -4883,7 +4883,7 @@ static int bpf_map_do_batch(const union bpf_attr *attr, return err; } -#define BPF_LINK_CREATE_LAST_FIELD link_create.uprobe_multi.flags +#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 f1442ef65ad7..2b77b75df6f3 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2987,6 +2987,7 @@ 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 { @@ -3012,6 +3013,8 @@ 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) @@ -3043,6 +3046,9 @@ 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(); @@ -3065,6 +3071,16 @@ 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) { @@ -3098,12 +3114,14 @@ 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 */ @@ -3147,6 +3165,15 @@ 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); @@ -3181,11 +3208,15 @@ 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); @@ -3214,6 +3245,8 @@ 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 2b6cd7d1c165..558902237338 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1642,6 +1642,7 @@ union bpf_attr { __aligned_u64 cookies; __u32 cnt; __u32 flags; + __u32 pid; } uprobe_multi; }; } link_create; -- 2.41.0