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Biederman" , Tycho Andersen , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/2] signal: add the "int si_code" arg to prepare_kill_siginfo() Message-ID: <20240209130620.GA8039@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1790426847081165316 X-GMAIL-MSGID: 1790426847081165316 So that do_tkill() can use this helper too. This also simplifies the next patch. TODO: perhaps we can kill prepare_kill_siginfo() and change the callers to use SEND_SIG_NOINFO, but this needs some changes in __send_signal_locked() and TP_STORE_SIGINFO(). Signed-off-by: Oleg Nesterov Reviewed-by: Christian Brauner Signed-off-by: Oleg Nesterov Signed-off-by: Christian Brauner Reviewed-by: Tycho Andersen --- kernel/signal.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index c3fac06937e2..a8199fda0d61 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -3793,12 +3793,12 @@ COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese, #endif #endif -static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info) +static void prepare_kill_siginfo(int sig, struct kernel_siginfo *info, int si_code) { clear_siginfo(info); info->si_signo = sig; info->si_errno = 0; - info->si_code = SI_USER; + info->si_code = si_code; info->si_pid = task_tgid_vnr(current); info->si_uid = from_kuid_munged(current_user_ns(), current_uid()); } @@ -3812,7 +3812,7 @@ SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) { struct kernel_siginfo info; - prepare_kill_siginfo(sig, &info); + prepare_kill_siginfo(sig, &info, SI_USER); return kill_something_info(sig, &info, pid); } @@ -3925,7 +3925,7 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL)) goto err; } else { - prepare_kill_siginfo(sig, &kinfo); + prepare_kill_siginfo(sig, &kinfo, SI_USER); } /* TODO: respect PIDFD_THREAD */ @@ -3970,12 +3970,7 @@ static int do_tkill(pid_t tgid, pid_t pid, int sig) { struct kernel_siginfo info; - clear_siginfo(&info); - info.si_signo = sig; - info.si_errno = 0; - info.si_code = SI_TKILL; - info.si_pid = task_tgid_vnr(current); - info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); + prepare_kill_siginfo(sig, &info, SI_TKILL); return do_send_specific(tgid, pid, sig, &info); } From patchwork Fri Feb 9 13:06:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleg Nesterov X-Patchwork-Id: 198857 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7300:50ea:b0:106:860b:bbdd with SMTP id r10csp840046dyd; Fri, 9 Feb 2024 05:11:41 -0800 (PST) X-Forwarded-Encrypted: i=3; AJvYcCXwo4VWmV4n0HTxk08GpMtZbG5DQ1bh+oYiYZEK1cx6qxE7iIYMyFRbGppHu1Xsd3lZ+eIYW5iGL9iGPBw0fhf7we8j1w== X-Google-Smtp-Source: AGHT+IGer/Xm6huAWGcQxU305Suky5dx6dl/JmyVDRasrdEYdRJhclt7ZPWFv1RceGyoJAtYEg/K X-Received: by 2002:a17:90a:ca81:b0:296:20fb:9d0d with SMTP id y1-20020a17090aca8100b0029620fb9d0dmr1370560pjt.28.1707484301164; Fri, 09 Feb 2024 05:11:41 -0800 (PST) ARC-Seal: i=2; a=rsa-sha256; t=1707484301; cv=pass; d=google.com; s=arc-20160816; b=WHFAGIauYILsSFHc8KPpPpc5fNqFReorBvagPII6RYSCq+fDOf88FJJgsCB5uiJgtX pOEzjD/diJqOHwWZTHDwIGKOvdYNRK4AaLt8WU2B/ns4J3gHM6Gx+ajLjmm7PjCJdLns W86VZ8027xhuchelR02RTu9IKUJONcec6uBX4lGMuTaJb4lYJoA3pG3V460ggzDXXK7R R/3DZtL88T6kTMUb4nNeEmA9kByNHME5QeSNbFVOktMgScQiIHeu+RTQXxTwG9xp7v+T 63Tbn1YKkvw8garQrqOwvL9xPpABkpFWOaM+TgVSs++De2KNDj/5OO9tVWt+FxCSis5q CCTA== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version :list-unsubscribe:list-subscribe:list-id:precedence:references :message-id:subject:cc:to:from:date:dkim-signature; bh=ETbj5B8vI9mqFeC8WBwO1d2T9IgzINe0mXcd/+60DO0=; fh=e0JflZz7HK7k07UvEMtBarL86FYJQpQVGETT3HCMo+A=; b=dLrpREJvMQSiXRWdaBnUS7eFGBpmZl0sJ7miEUGN4oXrmdgOJKCenXYPPTUCKWzqSy BSimXcQ71zgjlB5EOmlgVkKOfgQuDUTODfaMqzZAtN6PmObattXodL+Ae7q+4d/N5kBL WfVMqFAc+KtDOICHX/bXbdGQsAvywvmrm4YX3ffBVRLCRHjdrHEWjcsk8dEAqAYXv8Rv yCsG1rh6/aWkvFXkstjDE8ihw8nGY58u8uxh9o1dnvstJEbHgBSAksd2ZDTMzln3fPXo A/zX38IPRBMMvtFrFQdY/fuChlNlia9BuihqRU+bYkQlSNRiWMcNEI/+cLhGzkKQbuoP gHig==; dara=google.com ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=cPNmz+cV; arc=pass (i=1 spf=pass spfdomain=redhat.com dkim=pass dkdomain=redhat.com dmarc=pass fromdomain=redhat.com); spf=pass (google.com: domain of linux-kernel+bounces-59343-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) smtp.mailfrom="linux-kernel+bounces-59343-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com X-Forwarded-Encrypted: i=2; AJvYcCU8d2HYMJo2BeKGQ68SFCCvxnQiM2t6J01wdMi8hcGcv3BJAhtUDXku/FfE47NSoJYxHxQjCI1kzBIgcDvL1PEoJK3v0w== Received: from sy.mirrors.kernel.org (sy.mirrors.kernel.org. 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Biederman" , Tycho Andersen , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/2] pidfd: change pidfd_send_signal() to respect PIDFD_THREAD Message-ID: <20240209130650.GA8048@redhat.com> References: <20240209130620.GA8039@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240209130620.GA8039@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1790427058598477884 X-GMAIL-MSGID: 1790427058598477884 Turn kill_pid_info() into kill_pid_info_type(), this allows to pass any pid_type to group_send_sig_info(), despite its name it should work fine even if type = PIDTYPE_PID. Change pidfd_send_signal() to use PIDTYPE_PID or PIDTYPE_TGID depending on PIDFD_THREAD. While at it kill another TODO comment in pidfd_show_fdinfo(). As Christian expains fdinfo reports f_flags, userspace can already detect PIDFD_THREAD. Signed-off-by: Oleg Nesterov Reviewed-by: Christian Brauner Signed-off-by: Christian Brauner Reviewed-by: Tycho Andersen Signed-off-by: Christian Brauner Signed-off-by: Christian Brauner Reviewed-by: Oleg Nesterov --- kernel/fork.c | 2 -- kernel/signal.c | 38 ++++++++++++++++++++++---------------- 2 files changed, 22 insertions(+), 18 deletions(-) diff --git a/kernel/fork.c b/kernel/fork.c index cd61ca87d0e6..47b565598063 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2051,8 +2051,6 @@ static void pidfd_show_fdinfo(struct seq_file *m, struct file *f) seq_put_decimal_ll(m, "Pid:\t", nr); - /* TODO: report PIDFD_THREAD */ - #ifdef CONFIG_PID_NS seq_put_decimal_ll(m, "\nNSpid:\t", nr); if (nr > 0) { diff --git a/kernel/signal.c b/kernel/signal.c index a8199fda0d61..9578ce17d85d 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -47,6 +47,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include @@ -1436,7 +1437,8 @@ void lockdep_assert_task_sighand_held(struct task_struct *task) #endif /* - * send signal info to all the members of a group + * send signal info to all the members of a thread group or to the + * individual thread if type == PIDTYPE_PID. */ int group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p, enum pid_type type) @@ -1478,7 +1480,8 @@ int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp) return ret; } -int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid) +static int kill_pid_info_type(int sig, struct kernel_siginfo *info, + struct pid *pid, enum pid_type type) { int error = -ESRCH; struct task_struct *p; @@ -1487,11 +1490,10 @@ int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid) rcu_read_lock(); p = pid_task(pid, PIDTYPE_PID); if (p) - error = group_send_sig_info(sig, info, p, PIDTYPE_TGID); + error = group_send_sig_info(sig, info, p, type); rcu_read_unlock(); if (likely(!p || error != -ESRCH)) return error; - /* * The task was unhashed in between, try again. If it * is dead, pid_task() will return NULL, if we race with @@ -1500,6 +1502,11 @@ int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid) } } +int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid) +{ + return kill_pid_info_type(sig, info, pid, PIDTYPE_TGID); +} + static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid) { int error; @@ -3872,14 +3879,10 @@ static struct pid *pidfd_to_pid(const struct file *file) * @info: signal info * @flags: future flags * - * The syscall currently only signals via PIDTYPE_PID which covers - * kill(, . It does not signal threads or process - * groups. - * In order to extend the syscall to threads and process groups the @flags - * argument should be used. In essence, the @flags argument will determine - * what is signaled and not the file descriptor itself. Put in other words, - * grouping is a property of the flags argument not a property of the file - * descriptor. + * Send the signal to the thread group or to the individual thread depending + * on PIDFD_THREAD. + * In the future extension to @flags may be used to override the default scope + * of @pidfd. * * Return: 0 on success, negative errno on failure */ @@ -3890,6 +3893,7 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, struct fd f; struct pid *pid; kernel_siginfo_t kinfo; + bool thread; /* Enforce flags be set to 0 until we add an extension. */ if (flags) @@ -3910,6 +3914,8 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, if (!access_pidfd_pidns(pid)) goto err; + thread = f.file->f_flags & PIDFD_THREAD; + if (info) { ret = copy_siginfo_from_user_any(&kinfo, info); if (unlikely(ret)) @@ -3925,12 +3931,12 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL)) goto err; } else { - prepare_kill_siginfo(sig, &kinfo, SI_USER); + prepare_kill_siginfo(sig, &kinfo, + thread ? SI_TKILL : SI_USER); } - /* TODO: respect PIDFD_THREAD */ - ret = kill_pid_info(sig, &kinfo, pid); - + ret = kill_pid_info_type(sig, &kinfo, pid, + thread ? PIDTYPE_PID : PIDTYPE_TGID); err: fdput(f); return ret;