From nobody Tue Feb 10 04:23:32 2026 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 A6198202C44; Mon, 5 May 2025 11:14:18 +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=1746443659; cv=none; b=Cr13gSqBOwu0C/idsaBn1/BjqBy9srREgqC3wBgxCd9HXY4yZ1RthswKez3U+INxbI2Zop7Yt/dmAotW2maEurngS8/5yJQz4uilgc18mr4VkFF+ZJ2sDYJdrqSwRSUYKZuOeH4ZHotitV8Zybg6z23H6JDmbdHDt0groTJdb/g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746443659; c=relaxed/simple; bh=/uknDbEVxAQovH7hvslY3diyqJp2ptgrXNsx1BL3wHc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=goa5o+5yx6TsFhg/N3WJ5AJq1ypGLABmeMH7iE5rcZNAJskcl6mMmXLbwqn8BIjf8x1H2f6322Y4UqDz9U+YuJDzLBQEAa4hpghPqdGjrxJeXRkDaoTpMh8RWHJTMvkM2hU8ZPJgibi2NI8L/4KiY1LWbdkTME/U1b6+I8dabkU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SxOs8Qdp; 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="SxOs8Qdp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D59B0C4CEE4; Mon, 5 May 2025 11:14:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746443658; bh=/uknDbEVxAQovH7hvslY3diyqJp2ptgrXNsx1BL3wHc=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=SxOs8QdpRcwG0cRi+wlg9v8wO8QA0gftgcfF2/il8Y+UjNiDqrGeLnznp5sdnwLwD qyMuZRoVPu8gXt/5GUvtP5MKT9YpL1HSxujmYsAGNeOpgex5aHS2SRkh26jMJT0URA +vjLNNdAEKsamsEoYT7lzBfgHmNPNlQA01upJjMP4Yn+gbUXQIMsNHDk8hjRS3u2Xl LwrOjOiCX2B9euxmuaCXY4qlr/PwCGzwn2DA7N6CmaKPSDHirGGh6wZ8BtvCexCtx1 9gxuPw1WSlSrVWtWhbCsXX6j8rd9FMEwFsDpZyZqgvKIhXdWELzF5Tcoxd3lLgm7oh DBgJ4JtXI7D/Q== From: Christian Brauner Date: Mon, 05 May 2025 13:13:43 +0200 Subject: [PATCH RFC v3 05/10] coredump: validate socket name as it is written Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250505-work-coredump-socket-v3-5-e1832f0e1eae@kernel.org> References: <20250505-work-coredump-socket-v3-0-e1832f0e1eae@kernel.org> In-Reply-To: <20250505-work-coredump-socket-v3-0-e1832f0e1eae@kernel.org> To: Eric Dumazet , Kuniyuki Iwashima , Oleg Nesterov , linux-fsdevel@vger.kernel.org, Jann Horn Cc: "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, Christian Brauner , Alexander Mikhalitsyn X-Mailer: b4 0.15-dev-c25d1 X-Developer-Signature: v=1; a=openpgp-sha256; l=1280; i=brauner@kernel.org; h=from:subject:message-id; bh=/uknDbEVxAQovH7hvslY3diyqJp2ptgrXNsx1BL3wHc=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWRIzM1jlo9n8Jua97dx1aRDIfO1Qh23aO30E24Vfv31Q fy9m61/OkpZGMS4GGTFFFkc2k3C5ZbzVGw2ytSAmcPKBDKEgYtTACZy3Y3hnyWj5Kr/t/c2+fvE bPbO8v/Dxfw+f/HhnMTiw5N8lGTVHRn+yl03zHu/+cNCXaP0wvURG2++ufv01CFdlUObDnD4fFW 2ZAEA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 In contrast to other parameters written into /proc/sys/kernel/core_pattern that never fail we can validate enabling the new AF_UNIX support. This is obviously racy as hell but it's always been that way. Signed-off-by: Christian Brauner --- fs/coredump.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/fs/coredump.c b/fs/coredump.c index c60f86c473ad..d3f12ba0f150 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -1183,10 +1183,21 @@ void validate_coredump_safety(void) static int proc_dostring_coredump(const struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { - int error =3D proc_dostring(table, write, buffer, lenp, ppos); + int error; + ssize_t retval; + char old_core_pattern[CORENAME_MAX_SIZE]; + + retval =3D strscpy(old_core_pattern, core_pattern, CORENAME_MAX_SIZE); + + error =3D proc_dostring(table, write, buffer, lenp, ppos); + if (error) + return error; + if (core_pattern[0] =3D=3D '@' && strcmp(core_pattern, "@linuxafsk/coredu= mp.socket")) { + strscpy(core_pattern, old_core_pattern, retval + 1); + return -EINVAL; + } =20 - if (!error) - validate_coredump_safety(); + validate_coredump_safety(); return error; } =20 --=20 2.47.2