From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= Date: Sat, 19 Dec 2015 19:18:30 +0100 Message-Id: <1450549111-1297-2-git-send-email-mic@digikod.net> In-Reply-To: <1450549111-1297-1-git-send-email-mic@digikod.net> References: <1450549111-1297-1-git-send-email-mic@digikod.net> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Sender: linux-kernel-owner@vger.kernel.org Subject: [PATCH v4 1/2] um: Do not set unsecure permission for temporary file To: linux-kernel@vger.kernel.org Cc: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= , Jeff Dike , Richard Weinberger , Tristan Schmelcher , Greg Kroah-Hartman , user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net List-ID: Remove the insecure 0777 mode for temporary file to prohibit other user= s to change the executable mapped code. An attacker could gain access to the mapped file descriptor from the temporary file (before it is unlinked) in a read-only mode but it shoul= d not be accessible in write mode to avoid arbitrary code execution. To not change the hostfs behavior, the temporary file creation permission now depend on the current umask(2) and the implementation of mkstemp(3). Signed-off-by: Micka=C3=ABl Sala=C3=BCn Cc: Jeff Dike Cc: Richard Weinberger Acked-by: Tristan Schmelcher --- arch/um/os-Linux/mem.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/arch/um/os-Linux/mem.c b/arch/um/os-Linux/mem.c index 897e9ad..840d573 100644 --- a/arch/um/os-Linux/mem.c +++ b/arch/um/os-Linux/mem.c @@ -142,12 +142,6 @@ static int __init create_tmp_file(unsigned long lo= ng len) if (fd < 0) exit(1); =20 - err =3D fchmod(fd, 0777); - if (err < 0) { - perror("fchmod"); - exit(1); - } - /* * Seek to len - 1 because writing a character there will * increase the file size by one byte, to the desired length. --=20 2.6.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel"= in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/