Messages in this thread | | | Date | Thu, 26 Sep 2019 20:26:12 +0200 | From | Richard Kojedzinszky <> | Subject | Re: [PATCH] binfmt_elf: Do not move brk for INTERP-less ET_EXEC |
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Hi Kees,
Thanks for the quick patch. It seems my binaries start up well, and work as expected, as before.
Thanks again for the quick response.
Regards, Richard Kojedzinszky
2019-09-26 19:15 időpontban Kees Cook ezt írta: > When brk was moved for binaries without an interpreter, it should have > been limited to ET_DYN only. In other words, the special case was an > ET_DYN that lacks an INTERP, not just an executable that lacks INTERP. > The bug manifested for giant static executables, where the brk would > end > up in the middle of the text area on 32-bit architectures. > > Reported-by: Richard Kojedzinszky <richard@kojedz.in> > Fixes: bbdc6076d2e5 ("binfmt_elf: move brk out of mmap when doing > direct loader exec") > Cc: stable@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > Richard, are you able to test this? I'm able to run the gitea binary > with this change, and my INTERP-less ET_DYN tests (from the original > bug) continue to pass as well. > --- > fs/binfmt_elf.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c > index cec3b4146440..ad4c6b1d5074 100644 > --- a/fs/binfmt_elf.c > +++ b/fs/binfmt_elf.c > @@ -1121,7 +1121,8 @@ static int load_elf_binary(struct linux_binprm > *bprm) > * (since it grows up, and may collide early with the stack > * growing down), and into the unused ELF_ET_DYN_BASE region. > */ > - if (IS_ENABLED(CONFIG_ARCH_HAS_ELF_RANDOMIZE) && !interpreter) > + if (IS_ENABLED(CONFIG_ARCH_HAS_ELF_RANDOMIZE) && > + loc->elf_ex.e_type == ET_DYN && !interpreter) > current->mm->brk = current->mm->start_brk = > ELF_ET_DYN_BASE; > > -- > 2.17.1
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