Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kees Cook , Hector Marco-Gisbert , Ismael Ripoll Ripoll , Alexander Viro , "Kirill A. Shutemov" , Oleg Nesterov , Chen Gang , Michal Hocko , Konstantin Khlebnikov , Andrea Arcangeli , Andrey Ryabinin , Andrew Morton , Linus Torvalds , Ben Hutchings , Sasha Levin Subject: [PATCH 4.4 114/160] mm: refuse wrapped vm_brk requests Date: Mon, 19 Nov 2018 17:29:13 +0100 Message-Id: <20181119162641.808381922@linuxfoundation.org> In-Reply-To: <20181119162630.031306128@linuxfoundation.org> References: <20181119162630.031306128@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ commit ba093a6d9397da8eafcfbaa7d95bd34255da39a0 upstream. The vm_brk() alignment calculations should refuse to overflow. The ELF loader depending on this, but it has been fixed now. No other unsafe callers have been found. Link: http://lkml.kernel.org/r/1468014494-25291-3-git-send-email-keescook@chromium.org Signed-off-by: Kees Cook Reported-by: Hector Marco-Gisbert Cc: Ismael Ripoll Ripoll Cc: Alexander Viro Cc: "Kirill A. Shutemov" Cc: Oleg Nesterov Cc: Chen Gang Cc: Michal Hocko Cc: Konstantin Khlebnikov Cc: Andrea Arcangeli Cc: Andrey Ryabinin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 4.4: adjust context] Signed-off-by: Ben Hutchings Signed-off-by: Sasha Levin --- mm/mmap.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 39f5fbd07486..dd9205542a86 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2808,16 +2808,18 @@ static inline void verify_mm_writelocked(struct mm_struct *mm) * anonymous maps. eventually we may be able to do some * brk-specific accounting here. */ -static unsigned long do_brk(unsigned long addr, unsigned long len) +static unsigned long do_brk(unsigned long addr, unsigned long request) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma, *prev; - unsigned long flags; + unsigned long flags, len; struct rb_node **rb_link, *rb_parent; pgoff_t pgoff = addr >> PAGE_SHIFT; int error; - len = PAGE_ALIGN(len); + len = PAGE_ALIGN(request); + if (len < request) + return -ENOMEM; if (!len) return addr; -- 2.17.1