From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 86538414DF6; Fri, 4 Sep 2026 06:03:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788501822; cv=none; b=hBqG/KjVUigy3IC5g/y595UGr0E0PgJv/wOunm+lZcbe5e4UWJDsyTRtu7rtoll7m3/3Nc+ly5DbKJEWThfnrIU0i56US9nW+u3pdtbWHEDy+Q939DwPiwI7ktgjqAPT59k9QKOh9aPwwsbZ7Z26lZ0CAD5jleJUTHZ4qVMgBK0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788501822; c=relaxed/simple; bh=7XNxe6FNuuCClWFBFDlLYeyMp8/tQDAwnQfMSvdzCqU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QXwz45JmbQwRpiXwmNlCFxnrENGZR6CaSfUYhXvvTDvQR5uUBRsZbUXyBAOFrHF9tEhQwo5H1GP2A+g/fArVrbgLGCAxiJubYliJXXCJCbVZINt5wSgSL2N0hskhyPZ8ruXuXMwA8nQS5CjS8o6CweVVIjbizPFe+EWIxZCuZRo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1LJY/y2m; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="1LJY/y2m" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC4AD1F00A3D; Fri, 4 Sep 2026 06:03:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788501820; bh=2ZTYHEn9kmSsEBHbvtyHsayTnCti0OWRkFGkYC2ZbN4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=1LJY/y2mb6x7CenzX11JCRka6wRcPhZjjoLgX8k2OPGVNfzeqcW9T74G3LmgKQgGz uXMySavbznsSY3rLX+jsgf67sAlgi2l+n5g1yJSBdrK2UQRzJ7Uk1mxA4GlMasqFPy xGB8Whl5WiG0JjuYqdFzjp1gMbDGRSrKBjNT9qIg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Bradley Morgan , Oleg Nesterov , "Eric W. Biederman" , Adrian Huang , Aleksandr Nogikh , Christian Brauner , Marco Elver , "Masami Hiramatsu (Google)" , Mathieu Desnoyers , Peter Zijlstra , Steven Rostedt , Andrew Morton Subject: [PATCH 6.18 545/552] signal: avoid shared siginfo namespace rewrites Date: Fri, 4 Sep 2026 07:01:42 +0200 Message-ID: <20260904045802.959495408@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045747.813364717@linuxfoundation.org> References: <20260904045747.813364717@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bradley Morgan commit d19cdc167e696714509e87d3f7ae765b6e164589 upstream. send_signal_locked() rewrites sender ids for the target namespace. Group sends reuse the same siginfo, so one recipient can affect the next. Copy the siginfo before changing it. Link: https://lore.kernel.org/86a8857d58d43ee26a8b365b837fd24830343494.1782159692.git.include@grrlz.net Fixes: 7a0cf094944e ("signal: Correct namespace fixups of si_pid and si_uid") Signed-off-by: Bradley Morgan Acked-by: Oleg Nesterov Cc: "Eric W. Biederman" Cc: Adrian Huang Cc: Aleksandr Nogikh Cc: Christian Brauner Cc: Marco Elver Cc: "Masami Hiramatsu (Google)" Cc: Mathieu Desnoyers Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- kernel/signal.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1183,6 +1183,7 @@ static inline bool has_si_pid_and_uid(st int send_signal_locked(int sig, struct kernel_siginfo *info, struct task_struct *t, enum pid_type type) { + struct kernel_siginfo rewritten; /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */ bool force = false; @@ -1196,6 +1197,9 @@ int send_signal_locked(int sig, struct k /* SIGKILL and SIGSTOP is special or has ids */ struct user_namespace *t_user_ns; + rewritten = *info; + info = &rewritten; + rcu_read_lock(); t_user_ns = task_cred_xxx(t, user_ns); if (current_user_ns() != t_user_ns) {