4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Oscar Salvador <osalva...@suse.de> 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-osalva...@techadventures.net Signed-off-by: Oscar Salvador <osalva...@suse.de> Reported-by: syzbot+5dcb560fe12aa5091...@syzkaller.appspotmail.com Tested-by: Tetsuo Handa <penguin-ker...@i-love.sakura.ne.jp> Acked-by: Kees Cook <keesc...@chromium.org> Cc: Michal Hocko <mho...@suse.com> Cc: Nicolas Pitre <nicolas.pi...@linaro.org> Cc: <sta...@vger.kernel.org> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- fs/binfmt_elf.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1217,9 +1217,8 @@ 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 (error)
