| From: Oscar Salvador <osalvador@suse.de> |
| Date: Fri, 13 Jul 2018 16:59:13 -0700 |
| Subject: 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 <osalvador@suse.de> |
| Reported-by: syzbot+5dcb560fe12aa5091c06@syzkaller.appspotmail.com |
| Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> |
| Acked-by: Kees Cook <keescook@chromium.org> |
| Cc: Michal Hocko <mhocko@suse.com> |
| Cc: Nicolas Pitre <nicolas.pitre@linaro.org> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| fs/binfmt_elf.c | 5 ++--- |
| 1 file changed, 2 insertions(+), 3 deletions(-) |
| |
| --- a/fs/binfmt_elf.c |
| +++ b/fs/binfmt_elf.c |
| @@ -1083,9 +1083,8 @@ static int load_elf_library(struct 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)) |
