From patchwork Wed Jul 24 11:39:43 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Puranjay Mohan X-Patchwork-Id: 13740884 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 7775F157491; Wed, 24 Jul 2024 11:39:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721821199; cv=none; b=CFqmxm7r14E60Bqxzp9iiC4V+V7JCCq08prMHe106tFN3PbvsH4sswoU0Wj4upzu1inpj+doHljpfxyr35/oF46BH+xFNqMnv392OD3PaIqh/IcFDvK/4cylLwiWyCHlKS0bNDkMOlaePHdBjZrX5SAlueWeFuYJWC2IXPX3gdw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721821199; c=relaxed/simple; bh=TRLbiSG3uwVen1pBB1Ajq3MdLhJUNd5VKgOElz2rJYI=; h=From:To:Subject:Date:Message-Id:MIME-Version; b=oC4AJYnVmLq9/+QnyBWJfQ1ghbJsS1OhTALQEQHPdsR2LWrUGTBJkNTgai3v8oTUkKAG9qp3LAJK2JWHf3KAjqtd3CK9EqbqxdyhNY0BQb4o5JOcTmWz2KVHS3c1Rxv+7Cww7qvoRnhN8YE9n2IFdtGAxs6DSOdI1/O/XZLk0Bs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TNYbGmK2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TNYbGmK2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E38CAC32782; Wed, 24 Jul 2024 11:39:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1721821199; bh=TRLbiSG3uwVen1pBB1Ajq3MdLhJUNd5VKgOElz2rJYI=; h=From:To:Subject:Date:From; b=TNYbGmK2ibITmrRBNHwRgd0zAjyFXgvyKCGiKcjuKKkGZvoprg+PeQnDp7F2hOGat owFcpmxFmAhYjR7bGITleueb/Eo4CD0r536oC8ngNM9pX+y9ldbJ2Kk3sZNnSRrEmF qqBbovfcLg7sJ28cXY0Nitm16vsAHKYishffMGStM9mdXSeNBcctJtX+XXExtPfizM aY+k8eTYQJYe1B9d1zhN+qaorlY20ahlnIxFpB8pp7jW9FDJ8ll4v88Ak1Ord5+b+x J9w5ySVNprJvFiQL01TcVXTcxIJ8CiYPRnkVWDCWBg26h9ciwsPl4ntgisw0feTPkl 2LNrH2sdcxGwQ== From: Puranjay Mohan To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Matt Bobrowski , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Puranjay Mohan , Abhishek Chauhan , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH bpf-next 1/2] bpf: implement bpf_send_signal_pid/tgid() helpers Date: Wed, 24 Jul 2024 11:39:43 +0000 Message-Id: <20240724113944.75977-1-puranjay@kernel.org> X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Implement bpf_send_signal_pid and bpf_send_signal_tgid helpers which are similar to bpf_send_signal_thread and bpf_send_signal helpers respectively but can be used to send signals to other threads and processes. Signed-off-by: Puranjay Mohan --- include/uapi/linux/bpf.h | 37 ++++++++++++++++++++++++ kernel/trace/bpf_trace.c | 53 +++++++++++++++++++++++++++++----- tools/include/uapi/linux/bpf.h | 37 ++++++++++++++++++++++++ 3 files changed, 120 insertions(+), 7 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 35bcf52dbc65..7b29003c079c 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -5792,6 +5792,41 @@ union bpf_attr { * 0 on success. * * **-ENOENT** if the bpf_local_storage cannot be found. + * + * long bpf_send_signal_pid(u32 sig, u32 pid) + * Description + * Send signal *sig* to the thread corresponding to the + * process id *pid*. + * Return + * 0 on success or successfully queued. + * + * **-EBUSY** if work queue under nmi is full. + * + * **-EINVAL** if *sig* is invalid. + * + * **-EPERM** if no permission to send the *sig*. + * + * **-EAGAIN** if bpf program can try again. + * + * **-ESRCH** if *pid* is invalid. + * + * long bpf_send_signal_tgid(u32 sig, u32 tgid) + * Description + * Send signal *sig* to the process corresponding to the + * thread group id *tgid*. + * The signal may be delivered to any of this process's threads. + * Return + * 0 on success or successfully queued. + * + * **-EBUSY** if work queue under nmi is full. + * + * **-EINVAL** if *sig* is invalid. + * + * **-EPERM** if no permission to send the *sig*. + * + * **-EAGAIN** if bpf program can try again. + * + * **-ESRCH** if *tgid* is invalid. */ #define ___BPF_FUNC_MAPPER(FN, ctx...) \ FN(unspec, 0, ##ctx) \ @@ -6006,6 +6041,8 @@ union bpf_attr { FN(user_ringbuf_drain, 209, ##ctx) \ FN(cgrp_storage_get, 210, ##ctx) \ FN(cgrp_storage_delete, 211, ##ctx) \ + FN(send_signal_pid, 212, ##ctx) \ + FN(send_signal_tgid, 213, ##ctx) \ /* */ /* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index cd098846e251..f1e58122600d 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -839,21 +839,30 @@ static void do_bpf_send_signal(struct irq_work *entry) put_task_struct(work->task); } -static int bpf_send_signal_common(u32 sig, enum pid_type type) +static int bpf_send_signal_common(u32 sig, enum pid_type type, u32 pid) { struct send_signal_irq_work *work = NULL; + struct task_struct *tsk; + + if (pid) { + tsk = find_task_by_vpid(pid); + if (!tsk) + return -ESRCH; + } else { + tsk = current; + } /* Similar to bpf_probe_write_user, task needs to be * in a sound condition and kernel memory access be * permitted in order to send signal to the current * task. */ - if (unlikely(current->flags & (PF_KTHREAD | PF_EXITING))) + if (unlikely(tsk->flags & (PF_KTHREAD | PF_EXITING))) return -EPERM; if (unlikely(!nmi_uaccess_okay())) return -EPERM; /* Task should not be pid=1 to avoid kernel panic. */ - if (unlikely(is_global_init(current))) + if (unlikely(is_global_init(tsk))) return -EPERM; if (irqs_disabled()) { @@ -871,19 +880,19 @@ static int bpf_send_signal_common(u32 sig, enum pid_type type) * to the irq_work. The current task may change when queued * irq works get executed. */ - work->task = get_task_struct(current); + work->task = get_task_struct(tsk); work->sig = sig; work->type = type; irq_work_queue(&work->irq_work); return 0; } - return group_send_sig_info(sig, SEND_SIG_PRIV, current, type); + return group_send_sig_info(sig, SEND_SIG_PRIV, tsk, type); } BPF_CALL_1(bpf_send_signal, u32, sig) { - return bpf_send_signal_common(sig, PIDTYPE_TGID); + return bpf_send_signal_common(sig, PIDTYPE_TGID, 0); } static const struct bpf_func_proto bpf_send_signal_proto = { @@ -895,7 +904,7 @@ static const struct bpf_func_proto bpf_send_signal_proto = { BPF_CALL_1(bpf_send_signal_thread, u32, sig) { - return bpf_send_signal_common(sig, PIDTYPE_PID); + return bpf_send_signal_common(sig, PIDTYPE_PID, 0); } static const struct bpf_func_proto bpf_send_signal_thread_proto = { @@ -905,6 +914,32 @@ static const struct bpf_func_proto bpf_send_signal_thread_proto = { .arg1_type = ARG_ANYTHING, }; +BPF_CALL_2(bpf_send_signal_pid, u32, sig, u32, pid) +{ + return bpf_send_signal_common(sig, PIDTYPE_PID, pid); +} + +static const struct bpf_func_proto bpf_send_signal_pid_proto = { + .func = bpf_send_signal_pid, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_ANYTHING, + .arg2_type = ARG_ANYTHING, +}; + +BPF_CALL_2(bpf_send_signal_tgid, u32, sig, u32, tgid) +{ + return bpf_send_signal_common(sig, PIDTYPE_TGID, tgid); +} + +static const struct bpf_func_proto bpf_send_signal_tgid_proto = { + .func = bpf_send_signal_tgid, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_ANYTHING, + .arg2_type = ARG_ANYTHING, +}; + BPF_CALL_3(bpf_d_path, struct path *, path, char *, buf, u32, sz) { struct path copy; @@ -1583,6 +1618,10 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_send_signal_proto; case BPF_FUNC_send_signal_thread: return &bpf_send_signal_thread_proto; + case BPF_FUNC_send_signal_pid: + return &bpf_send_signal_pid_proto; + case BPF_FUNC_send_signal_tgid: + return &bpf_send_signal_tgid_proto; case BPF_FUNC_perf_event_read_value: return &bpf_perf_event_read_value_proto; case BPF_FUNC_ringbuf_output: diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 35bcf52dbc65..7b29003c079c 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -5792,6 +5792,41 @@ union bpf_attr { * 0 on success. * * **-ENOENT** if the bpf_local_storage cannot be found. + * + * long bpf_send_signal_pid(u32 sig, u32 pid) + * Description + * Send signal *sig* to the thread corresponding to the + * process id *pid*. + * Return + * 0 on success or successfully queued. + * + * **-EBUSY** if work queue under nmi is full. + * + * **-EINVAL** if *sig* is invalid. + * + * **-EPERM** if no permission to send the *sig*. + * + * **-EAGAIN** if bpf program can try again. + * + * **-ESRCH** if *pid* is invalid. + * + * long bpf_send_signal_tgid(u32 sig, u32 tgid) + * Description + * Send signal *sig* to the process corresponding to the + * thread group id *tgid*. + * The signal may be delivered to any of this process's threads. + * Return + * 0 on success or successfully queued. + * + * **-EBUSY** if work queue under nmi is full. + * + * **-EINVAL** if *sig* is invalid. + * + * **-EPERM** if no permission to send the *sig*. + * + * **-EAGAIN** if bpf program can try again. + * + * **-ESRCH** if *tgid* is invalid. */ #define ___BPF_FUNC_MAPPER(FN, ctx...) \ FN(unspec, 0, ##ctx) \ @@ -6006,6 +6041,8 @@ union bpf_attr { FN(user_ringbuf_drain, 209, ##ctx) \ FN(cgrp_storage_get, 210, ##ctx) \ FN(cgrp_storage_delete, 211, ##ctx) \ + FN(send_signal_pid, 212, ##ctx) \ + FN(send_signal_tgid, 213, ##ctx) \ /* */ /* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't