Hi! > [ Upstream commit 2a97388a807b6ab5538aa8f8537b2463c6988bd2 ] > > ELF loader uses "randomize_va_space" twice. It is sysctl and can change > at any moment, so 2 loads could see 2 different values in theory with > unpredictable consequences. > > Issue exactly one load for consistent value across one exec. > > Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx> > Link: https://lore.kernel.org/r/3329905c-7eb8-400a-8f0a-d87cff979b5b@p183 > Signed-off-by: Kees Cook <kees@xxxxxxxxxx> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > --- > fs/binfmt_elf.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c > index c41c568ad1b8a..af8830878fa0b 100644 > --- a/fs/binfmt_elf.c > +++ b/fs/binfmt_elf.c > @@ -876,7 +876,8 @@ static int load_elf_binary(struct linux_binprm *bprm) > if (elf_read_implies_exec(loc->elf_ex, executable_stack)) > current->personality |= READ_IMPLIES_EXEC; > > - if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) > + const int snapshot_randomize_va_space = READ_ONCE(randomize_va_space); > + if (!(current->personality & ADDR_NO_RANDOMIZE) && snapshot_randomize_va_space) > current->flags |= PF_RANDOMIZE; > > setup_new_exec(bprm); We normally put variable declaration at start of the function. I'd not be surprised if this broke with older compilers. Best regards, Pavel -- DENX Software Engineering GmbH, Managing Director: Erika Unter HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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