From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-2753674-1521195496-2-14655612768245549357 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='us-ascii' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1521195495; b=CIANmae22qgbs3t/cqSLTyTShbEiII1MDEuy3ONrofRH9Iw y6GI2NldpmYkXyIW3KWkqOXWF1qSokqPBNQ88RbtD1U6kNhzT4D2Rm6HP3ocz3Ci 9mjrMz0sdZEoLdTBp80hKFtZcLGgTKEK9NmTRVO66aQ6CAchjsb4ZGa+RWdvOEkt ryn55qH1W7CZtm0xpNdEWnIJBOuPxgdx55JPygXTZu0qfmAXcFTaqEYB45pGNocD +ZrZdZb9AEm+XjWhdE+rsbrIvguZleHC0ogRLgfvGpaN3DzsTT6j54nFJqNZ+YEp IUjxJjR1YlMjCTrLJzA/Qjom44svpzeC21hoAqw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to:sender :list-id; s=arctest; t=1521195495; bh=NihGyx+3MFwcOBYoQAOHYQTiVB aDCQEEUYGX7nBQ4og=; b=P1OydsUSuyzwRvfQLSZ5AjA5J6sKnMfTDO4KXOgaW/ 66r2HnhkgdeAGAzzA70CJQSKyOspY7iUGg6/wjZn1mDJEwMjCZCYx1qAbrE4zhun HwXJE8e4IQ3S5A7Uus+65tlY43yzkZLALXLLXw2BaFl4hXtuYCSwP+68zywZV7NU V7hI1m7YSeRyrdjh/jRVuEOkEM8B3+SUk45Gt/xq+AW1OgrcDe7IgIXBEzzZnGQp qaTelGX6LOwE1tcQIp2eDTA9V+6/GoiMgLN6wOMNup9mkNDMbH5nbdEPN9369VYP XIm5LYLfatgyijrgj7lb+zy+esFNlmkTQq6n+ZszF/+g== ARC-Authentication-Results: i=1; mx5.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=kernel.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=orgdomain_pass; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=kernel.org header.result=pass header_is_org_domain=yes Authentication-Results: mx5.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=kernel.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=orgdomain_pass; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=kernel.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753188AbeCPKSC (ORCPT ); Fri, 16 Mar 2018 06:18:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:35481 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751637AbeCPKSB (ORCPT ); Fri, 16 Mar 2018 06:18:01 -0400 Date: Fri, 16 Mar 2018 11:17:57 +0100 From: Michal Hocko To: Mike Kravetz Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, bugzilla-daemon@bugzilla.kernel.org, "Kirill A . Shutemov" , Nic Losby , Yisheng Xie , Andrew Morton , stable@vger.kernel.org Subject: Re: [PATCH v3] hugetlbfs: check for pgoff value overflow Message-ID: <20180316101757.GE23100@dhcp22.suse.cz> References: <20180306133135.4dc344e478d98f0e29f47698@linux-foundation.org> <20180309002726.7248-1-mike.kravetz@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180309002726.7248-1-mike.kravetz@oracle.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Thu 08-03-18 16:27:26, Mike Kravetz wrote: > A vma with vm_pgoff large enough to overflow a loff_t type when > converted to a byte offset can be passed via the remap_file_pages > system call. The hugetlbfs mmap routine uses the byte offset to > calculate reservations and file size. > > A sequence such as: > mmap(0x20a00000, 0x600000, 0, 0x66033, -1, 0); > remap_file_pages(0x20a00000, 0x600000, 0, 0x20000000000000, 0); > will result in the following when task exits/file closed, > kernel BUG at mm/hugetlb.c:749! > Call Trace: > hugetlbfs_evict_inode+0x2f/0x40 > evict+0xcb/0x190 > __dentry_kill+0xcb/0x150 > __fput+0x164/0x1e0 > task_work_run+0x84/0xa0 > exit_to_usermode_loop+0x7d/0x80 > do_syscall_64+0x18b/0x190 > entry_SYSCALL_64_after_hwframe+0x3d/0xa2 > > The overflowed pgoff value causes hugetlbfs to try to set up a > mapping with a negative range (end < start) that leaves invalid > state which causes the BUG. > > The previous overflow fix to this code was incomplete and did not > take the remap_file_pages system call into account. > > Fixes: 045c7a3f53d9 ("hugetlbfs: fix offset overflow in hugetlbfs mmap") > Cc: > Reported-by: Nic Losby > Signed-off-by: Mike Kravetz OK, looks good to me. Hairy but seems to be the easiest way around this. Acked-by: Michal Hocko > --- > Changes in v3 > * Use a simpler mask computation as suggested by Andrew Morton > Changes in v2 > * Use bitmask for overflow check as suggested by Yisheng Xie > * Add explicit (from > to) check when setting up reservations > * Cc stable > > fs/hugetlbfs/inode.c | 16 +++++++++++++--- > mm/hugetlb.c | 6 ++++++ > 2 files changed, 19 insertions(+), 3 deletions(-) > > diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c > index 8fe1b0aa2896..e46117dc006a 100644 > --- a/fs/hugetlbfs/inode.c > +++ b/fs/hugetlbfs/inode.c > @@ -108,6 +108,15 @@ static void huge_pagevec_release(struct pagevec *pvec) > pagevec_reinit(pvec); > } > > +/* > + * Mask used when checking the page offset value passed in via system > + * calls. This value will be converted to a loff_t which is signed. > + * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the > + * value. The extra bit (- 1 in the shift value) is to take the sign > + * bit into account. > + */ > +#define PGOFF_LOFFT_MAX (PAGE_MASK << (BITS_PER_LONG - (2 * PAGE_SHIFT) - 1)) > + > static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) > { > struct inode *inode = file_inode(file); > @@ -127,12 +136,13 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) > vma->vm_ops = &hugetlb_vm_ops; > > /* > - * Offset passed to mmap (before page shift) could have been > - * negative when represented as a (l)off_t. > + * page based offset in vm_pgoff could be sufficiently large to > + * overflow a (l)off_t when converted to byte offset. > */ > - if (((loff_t)vma->vm_pgoff << PAGE_SHIFT) < 0) > + if (vma->vm_pgoff & PGOFF_LOFFT_MAX) > return -EINVAL; > > + /* must be huge page aligned */ > if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT)) > return -EINVAL; > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 7c204e3d132b..8eeade0a0b7a 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -4374,6 +4374,12 @@ int hugetlb_reserve_pages(struct inode *inode, > struct resv_map *resv_map; > long gbl_reserve; > > + /* This should never happen */ > + if (from > to) { > + VM_WARN(1, "%s called with a negative range\n", __func__); > + return -EINVAL; > + } > + > /* > * Only apply hugepage reservation if asked. At fault time, an > * attempt will be made for VM_NORESERVE to allocate a page > -- > 2.13.6 -- Michal Hocko SUSE Labs