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 D6650205502; Fri, 16 May 2025 11:25:57 +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=1747394758; cv=none; b=JxVVlv7lmTwzl4TAZjykCTvBRpf0L9g5Ogx6h9mp+UigIIx38RJL069S7fTX9c7E9FtG2/mRrlRgWJLHxqK6TI2XU5sp1dOA84UOAu4IGt31AHqE7vKoefvHEFJUD2a8bVN9+mWppOhWbSpVivPYXWfzH2AjUTBBetH/gCnSRAo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747394758; c=relaxed/simple; bh=ko2BjK77OT+gmmXf5cdOJrFqFr0W5DbZFPX/gNkIr84=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=E9iyBpl4dXiixk0RtYoTAzxVrUN8iWDjwyDioFgBskCdyTPbRNt5lXRtD8T7T2rXKVVQR6PV3NxFmFbIf58oeCH0qyzsjn4GXComewQuGg0V/TZ2qYdIDuj/Zbe9ZxksNKvTdb1EFyrVpaM4toUBNreYGCcvbduZDplSDrI+Q60= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Co7OiZ12; 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="Co7OiZ12" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3EE6C4CEE4; Fri, 16 May 2025 11:25:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747394757; bh=ko2BjK77OT+gmmXf5cdOJrFqFr0W5DbZFPX/gNkIr84=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=Co7OiZ126uEXurIc0JVM+7N6XOb1KpZg6YoZ2vvH2AFYesv5nfZ1PWdOwxZy7+MEq 85ncbEN8tkfDhzKRLo4Np1h5qckf6qT2XcH+KhCF+uYMBd4IT/fTFnUkKvUco44D8w js8zwm15qtVtx5Avb8w9f4/g/XciemlqgAlSPiFxekNYiUmu296CEaXLmTO5pNHEUt /Z12QGFkPmy9hOF28f5acw3t+PtfsyCYPzMPtF6lYarmjdojQE5saEz+RE1ozJqSF7 y+ciKXTKfCoK3NQT7cvHSgoM12DkLNwZ4PmEU7xzUUcELQMWvWaAcEG0g5AxXxtwsX 1OAHPHXjDRnJA== From: Christian Brauner Date: Fri, 16 May 2025 13:25:29 +0200 Subject: [PATCH v8 2/9] coredump: massage do_coredump() Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20250516-work-coredump-socket-v8-2-664f3caf2516@kernel.org> References: <20250516-work-coredump-socket-v8-0-664f3caf2516@kernel.org> In-Reply-To: <20250516-work-coredump-socket-v8-0-664f3caf2516@kernel.org> To: linux-fsdevel@vger.kernel.org, Jann Horn , Daniel Borkmann , Kuniyuki Iwashima Cc: Eric Dumazet , Oleg Nesterov , "David S. Miller" , Alexander Viro , Daan De Meyer , David Rheinsberg , Jakub Kicinski , Jan Kara , Lennart Poettering , Luca Boccassi , Mike Yuan , Paolo Abeni , Simon Horman , =?utf-8?q?Zbigniew_J=C4=99drzejewski-Szmek?= , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-security-module@vger.kernel.org, Christian Brauner , Alexander Mikhalitsyn X-Mailer: b4 0.15-dev-6f78e X-Developer-Signature: v=1; a=openpgp-sha256; l=5079; i=brauner@kernel.org; h=from:subject:message-id; bh=ko2BjK77OT+gmmXf5cdOJrFqFr0W5DbZFPX/gNkIr84=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWSoK2ydeeTLkos1zkeEH3DolMSIvV0SkrZ316cz2arKf y9cCNiv21HKwiDGxSArpsji0G4SLrecp2KzUaYGzBxWJpAhDFycAjCRT0qMDPfOh39cz/p841k7 qwlX3os3LbQJmbFx7znFzbyzdJl/vqlmZGhpdj83t/96xO7Ssx+/Jl0tlDnX+9v3/wSLfv5IpTN ptVwA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 We're going to extend the coredump code in follow-up patches. Clean it up so we can do this more easily. Acked-by: Luca Boccassi Reviewed-by: Jann Horn Reviewed-by: Alexander Mikhalitsyn Signed-off-by: Christian Brauner --- fs/coredump.c | 122 +++++++++++++++++++++++++++++++--------------------------- 1 file changed, 65 insertions(+), 57 deletions(-) diff --git a/fs/coredump.c b/fs/coredump.c index 45725465c299..47c811d32028 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -643,63 +643,8 @@ void do_coredump(const kernel_siginfo_t *siginfo) goto fail_unlock; } - if (cn.core_type == COREDUMP_PIPE) { - int argi; - int dump_count; - char **helper_argv; - struct subprocess_info *sub_info; - - if (cprm.limit == 1) { - /* See umh_coredump_setup() which sets RLIMIT_CORE = 1. - * - * Normally core limits are irrelevant to pipes, since - * we're not writing to the file system, but we use - * cprm.limit of 1 here as a special value, this is a - * consistent way to catch recursive crashes. - * We can still crash if the core_pattern binary sets - * RLIM_CORE = !1, but it runs as root, and can do - * lots of stupid things. - * - * Note that we use task_tgid_vnr here to grab the pid - * of the process group leader. That way we get the - * right pid if a thread in a multi-threaded - * core_pattern process dies. - */ - coredump_report_failure("RLIMIT_CORE is set to 1, aborting core"); - goto fail_unlock; - } - cprm.limit = RLIM_INFINITY; - - dump_count = atomic_inc_return(&core_dump_count); - if (core_pipe_limit && (core_pipe_limit < dump_count)) { - coredump_report_failure("over core_pipe_limit, skipping core dump"); - goto fail_dropcount; - } - - helper_argv = kmalloc_array(argc + 1, sizeof(*helper_argv), - GFP_KERNEL); - if (!helper_argv) { - coredump_report_failure("%s failed to allocate memory", __func__); - goto fail_dropcount; - } - for (argi = 0; argi < argc; argi++) - helper_argv[argi] = cn.corename + argv[argi]; - helper_argv[argi] = NULL; - - retval = -ENOMEM; - sub_info = call_usermodehelper_setup(helper_argv[0], - helper_argv, NULL, GFP_KERNEL, - umh_coredump_setup, NULL, &cprm); - if (sub_info) - retval = call_usermodehelper_exec(sub_info, - UMH_WAIT_EXEC); - - kfree(helper_argv); - if (retval) { - coredump_report_failure("|%s pipe failed", cn.corename); - goto close_fail; - } - } else if (cn.core_type == COREDUMP_FILE) { + switch (cn.core_type) { + case COREDUMP_FILE: { struct mnt_idmap *idmap; struct inode *inode; int open_flags = O_CREAT | O_WRONLY | O_NOFOLLOW | @@ -793,6 +738,69 @@ void do_coredump(const kernel_siginfo_t *siginfo) if (do_truncate(idmap, cprm.file->f_path.dentry, 0, 0, cprm.file)) goto close_fail; + break; + } + case COREDUMP_PIPE: { + int argi; + int dump_count; + char **helper_argv; + struct subprocess_info *sub_info; + + if (cprm.limit == 1) { + /* See umh_coredump_setup() which sets RLIMIT_CORE = 1. + * + * Normally core limits are irrelevant to pipes, since + * we're not writing to the file system, but we use + * cprm.limit of 1 here as a special value, this is a + * consistent way to catch recursive crashes. + * We can still crash if the core_pattern binary sets + * RLIM_CORE = !1, but it runs as root, and can do + * lots of stupid things. + * + * Note that we use task_tgid_vnr here to grab the pid + * of the process group leader. That way we get the + * right pid if a thread in a multi-threaded + * core_pattern process dies. + */ + coredump_report_failure("RLIMIT_CORE is set to 1, aborting core"); + goto fail_unlock; + } + cprm.limit = RLIM_INFINITY; + + dump_count = atomic_inc_return(&core_dump_count); + if (core_pipe_limit && (core_pipe_limit < dump_count)) { + coredump_report_failure("over core_pipe_limit, skipping core dump"); + goto fail_dropcount; + } + + helper_argv = kmalloc_array(argc + 1, sizeof(*helper_argv), + GFP_KERNEL); + if (!helper_argv) { + coredump_report_failure("%s failed to allocate memory", __func__); + goto fail_dropcount; + } + for (argi = 0; argi < argc; argi++) + helper_argv[argi] = cn.corename + argv[argi]; + helper_argv[argi] = NULL; + + retval = -ENOMEM; + sub_info = call_usermodehelper_setup(helper_argv[0], + helper_argv, NULL, GFP_KERNEL, + umh_coredump_setup, NULL, &cprm); + if (sub_info) + retval = call_usermodehelper_exec(sub_info, + UMH_WAIT_EXEC); + + kfree(helper_argv); + if (retval) { + coredump_report_failure("|%s pipe failed", cn.corename); + goto close_fail; + } + break; + } + default: + WARN_ON_ONCE(true); + goto close_fail; } /* get us an unshared descriptor table; almost always a no-op */ -- 2.47.2