From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x225dOJtGCIqOVWenpXJB45HPZCayggoalA/WjT2OQsNrkCHhM60qSVg+csOqat+z/dhPmy9Y ARC-Seal: i=1; a=rsa-sha256; t=1517855058; cv=none; d=google.com; s=arc-20160816; b=QV1Fe0lU3JQde+J1Q1ncCiAyENbNDdercgnDW8lJiwHzIJvLzpdGLhly4+mKJRl9oy eQMrr1z4zARc8ebYziMswlC91YCnDMcZoDMBH5Q/NHaLNL2sMgxoBAs8eyo0V5506aoi qAL0Pocbr29wAKYX9jLOAkQ/QZyNlMOUqyTVzrEc30xAA9GTXxEHqfyBU2ukVSb87vsY 8UvuuxLatb7GZxFbsKDCLVq6eya1s+WrUkAOtR/ZSqEteKRksoMiLujvZvsK4Ip9xXas 3OboZiA4c54xWYwcqpXxutog/uKwJErul7K08lWRhnPJKud+A4jmkKGkKHbxLO+btNrX rPtw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=kKhKOSRAGTEduYDqevxQ6blkPRq46uEfRph7UuT/UHs=; b=MRY/d4u4tpAId3G4PmKFn8XsEVmFMsXBwUfyebjZI+DVhb1pjmbBcJ9i0/4IKWfdr3 ekay0FGZudXswcxiL9YnV0t8E8c6v51dyFoKP6SfKyXCOp5R8JkHyONgwLNF4Y/YqxvI yd+9HppktGx8RdA81NIR7FeuUEelrXJSMojd0PVfof6fZkLoPf4mhO5CyrfAWVJabRim akGonahA4HWdxsYV6PO8Vu6yR1heFxRfdjBK7Afpfv3YeubHwVBjZdcKYoNLPiJPvD0t sKBaIuw1GwAxnxsMQ0jDwacoLkmfKMp8jkvmiWvOlU150P/l3UiS1hyMFI+YBRTzbDVf lgEA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 104.132.1.108 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 104.132.1.108 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Williams , Thomas Gleixner , linux-arch@vger.kernel.org, kernel-hardening@lists.openwall.com, Al Viro , torvalds@linux-foundation.org, alan@linux.intel.com Subject: [PATCH 4.14 45/64] vfs, fdtable: Prevent bounds-check bypass via speculative execution Date: Mon, 5 Feb 2018 10:23:04 -0800 Message-Id: <20180205182140.422732097@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180205182138.571333346@linuxfoundation.org> References: <20180205182138.571333346@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1591586385988984097?= X-GMAIL-MSGID: =?utf-8?q?1591586385988984097?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dan Williams dan.j.williams@intel.com commit 56c30ba7b348b90484969054d561f711ba196507 'fd' is a user controlled value that is used as a data dependency to read from the 'fdt->fd' array. In order to avoid potential leaks of kernel memory values, block speculative execution of the instruction stream that could issue reads based on an invalid 'file *' returned from __fcheck_files. Co-developed-by: Elena Reshetova Signed-off-by: Dan Williams Signed-off-by: Thomas Gleixner Cc: linux-arch@vger.kernel.org Cc: kernel-hardening@lists.openwall.com Cc: gregkh@linuxfoundation.org Cc: Al Viro Cc: torvalds@linux-foundation.org Cc: alan@linux.intel.com Link: https://lkml.kernel.org/r/151727418500.33451.17392199002892248656.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Greg Kroah-Hartman --- include/linux/fdtable.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/include/linux/fdtable.h +++ b/include/linux/fdtable.h @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -82,8 +83,10 @@ static inline struct file *__fcheck_file { struct fdtable *fdt = rcu_dereference_raw(files->fdt); - if (fd < fdt->max_fds) + if (fd < fdt->max_fds) { + fd = array_index_nospec(fd, fdt->max_fds); return rcu_dereference_raw(fdt->fd[fd]); + } return NULL; }