From db2858f193dd9b3808fb180f1dbada87b3e41ba4 Mon Sep 17 00:00:00 2001 From: Oscar Salvador Date: Fri, 13 Jul 2018 16:59:13 -0700 Subject: [PATCH] fs, elf: make sure to page align bss in load_elf_library 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 Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- 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 1fdf4e5bf8c6..a4fabf60d5ee 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1217,9 +1217,8 @@ 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 (error) -- 2.20.1