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 E500C25A2C1; Mon, 12 May 2025 08:55:51 +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=1747040152; cv=none; b=lWIbJhA5C7qIhxp4cd/mEQOfXQw8aTOLlOwLm8dtt8Ks/GCo49cdHE8mpIAGl81HRlVm4ElTDhp8Q9eSJ0wIo8uxZ2QhqZdR11/1xp9I/OfexJdZpxYXwVMCqluC3sp4wiSJPiHeQH4WLf6M23OPSjXrNmCP/KqX0miI9bTm/lM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747040152; c=relaxed/simple; bh=A1ET0rfOsbnb/BsO8UCsIl2X+TJza69sCPkeWIG0Ss8=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=gEdhHuDO2PY6N1wFRa/8RqcVOwACluTnLdkUro38SRAc7LBekzPQ+JHxbmiCutgyZ5/IujsSsBCl9hjnOIBg4AXPPX4w7eDmIhjl+ak0V0bj1E9eAenWYW7qH7KxNdpIjKalvBJRjT208nB5EIXA6cpl9RHTeZVpEWTRlJmX+9Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=I3i81WPB; 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="I3i81WPB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 99426C4CEEF; Mon, 12 May 2025 08:55:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747040151; bh=A1ET0rfOsbnb/BsO8UCsIl2X+TJza69sCPkeWIG0Ss8=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=I3i81WPB1UdV+yufEcuRKKWxMH5xySmzTOXqB9537sr0Z91xLH5+rR0Ynd6KzDTLd xGgdHflc4rNJfZQGoUgb4MFHTTEaJM7ISrGTu5V3S/91uFxXbninrvbJoMwQrbaNqL 1/WQdV7eAtiyuKGSrqsqdzKGfGM93gyT1PvXIe0KdZ4NHdJ92Y87OYq5zEx98NPVKt +aBZkUpAaiz8QNQgb7KOq1zhzf/Fdy/0e1m+gZNKloTybvstTeaVgwMw0IOidbTrSc 5yTORGpwc3SV5XgyT4UfYnTSgRlLltWdQNRHJDdIni2LIkHWBjD2YXIZhcZZCU0LAn bG6gtFYD9Mjog== From: Christian Brauner Date: Mon, 12 May 2025 10:55:21 +0200 Subject: [PATCH v6 2/9] coredump: massage do_coredump() Precedence: bulk X-Mailing-List: linux-fsdevel@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: <20250512-work-coredump-socket-v6-2-c51bc3450727@kernel.org> References: <20250512-work-coredump-socket-v6-0-c51bc3450727@kernel.org> In-Reply-To: <20250512-work-coredump-socket-v6-0-c51bc3450727@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-c25d1 X-Developer-Signature: v=1; a=openpgp-sha256; l=4911; i=brauner@kernel.org; h=from:subject:message-id; bh=A1ET0rfOsbnb/BsO8UCsIl2X+TJza69sCPkeWIG0Ss8=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWQobm+/oHjVWKjHJqy2b6ovj8ek+gK2mjzFgqSjG6/aN TAKrEjsKGVhEONikBVTZHFoNwmXW85TsdkoUwNmDisTyBAGLk4BmIi3BiPDMb5e00I+rqpKfmMv MbldE56Zn1/u8bHxprlMclae4XReoAqdpezzWhkfLqpTsWn/8/NqDxOfTGD+lqOtHY/yTsamsQM A 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. 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 368751d98781..0e97c21b35e3 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -646,63 +646,8 @@ 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 | @@ -796,6 +741,69 @@ 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