Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oscar Salvador , syzbot+5dcb560fe12aa5091c06@syzkaller.appspotmail.com, Tetsuo Handa , Kees Cook , Michal Hocko , Nicolas Pitre , Andrew Morton , Linus Torvalds , Ben Hutchings , Sasha Levin Subject: [PATCH 4.4 115/160] fs, elf: make sure to page align bss in load_elf_library Date: Mon, 19 Nov 2018 17:29:14 +0100 Message-Id: <20181119162641.879208238@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 24962af7e1041b7e50c1bc71d8d10dc678c556b5 upstream. The current code does not make sure to page align bss before calling vm_brk(), and this can lead to a VM_BUG_ON() in __mm_populate() due to the requested lenght not being correctly aligned. Let us make sure to align it properly. Kees: only applicable to CONFIG_USELIB kernels: 32-bit and configured for libc5. Link: http://lkml.kernel.org/r/20180705145539.9627-1-osalvador@techadventures.net Signed-off-by: Oscar Salvador Reported-by: syzbot+5dcb560fe12aa5091c06@syzkaller.appspotmail.com Tested-by: Tetsuo Handa Acked-by: Kees Cook Cc: Michal Hocko Cc: Nicolas Pitre Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings Signed-off-by: Sasha Levin --- fs/binfmt_elf.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 2963a23f7a80..f010d6c8dd14 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1214,9 +1214,8 @@ static int load_elf_library(struct file *file) goto out_free_ph; } - len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr + - ELF_MIN_ALIGN - 1); - bss = eppnt->p_memsz + eppnt->p_vaddr; + len = ELF_PAGEALIGN(eppnt->p_filesz + eppnt->p_vaddr); + bss = ELF_PAGEALIGN(eppnt->p_memsz + eppnt->p_vaddr); if (bss > len) { error = vm_brk(len, bss - len); if (BAD_ADDR(error)) -- 2.17.1