binfmt: Move install_exec_creds after setup_new_exec to match binfmt_elf

[ Upstream commit e7f7785449 ]

In 2016 Linus moved install_exec_creds immediately after
setup_new_exec, in binfmt_elf as a cleanup and as part of closing a
potential information leak.

Perform the same cleanup for the other binary formats.

Different binary formats doing the same things the same way makes exec
easier to reason about and easier to maintain.

Greg Ungerer reports:
> I tested the the whole series on non-MMU m68k and non-MMU arm
> (exercising binfmt_flat) and it all tested out with no problems,
> so for the binfmt_flat changes:
Tested-by: Greg Ungerer <gerg@linux-m68k.org>

Ref: 9f834ec18d ("binfmt_elf: switch to new creds when switching to new mm")
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Stable-dep-of: e7f703ff25 ("binfmt: Fix error return code in load_elf_fdpic_binary()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Eric W. Biederman 2020-03-12 10:17:17 -05:00 committed by Greg Kroah-Hartman
parent 3cdd91a916
commit 33933af45d
4 changed files with 4 additions and 6 deletions

View File

@ -140,6 +140,7 @@ static int load_aout_binary(struct linux_binprm *bprm)
set_personality_ia32(false);
setup_new_exec(bprm);
install_exec_creds(bprm);
regs->cs = __USER32_CS;
regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
@ -156,8 +157,6 @@ static int load_aout_binary(struct linux_binprm *bprm)
if (retval < 0)
return retval;
install_exec_creds(bprm);
if (N_MAGIC(ex) == OMAGIC) {
unsigned long text_addr, map_size;

View File

@ -162,6 +162,7 @@ static int load_aout_binary(struct linux_binprm * bprm)
set_personality(PER_LINUX);
#endif
setup_new_exec(bprm);
install_exec_creds(bprm);
current->mm->end_code = ex.a_text +
(current->mm->start_code = N_TXTADDR(ex));
@ -174,7 +175,6 @@ static int load_aout_binary(struct linux_binprm * bprm)
if (retval < 0)
return retval;
install_exec_creds(bprm);
if (N_MAGIC(ex) == OMAGIC) {
unsigned long text_addr, map_size;

View File

@ -353,6 +353,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
current->personality |= READ_IMPLIES_EXEC;
setup_new_exec(bprm);
install_exec_creds(bprm);
set_binfmt(&elf_fdpic_format);
@ -434,7 +435,6 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
current->mm->start_stack = current->mm->start_brk + stack_size;
#endif
install_exec_creds(bprm);
if (create_elf_fdpic_tables(bprm, current->mm,
&exec_params, &interp_params) < 0)
goto error;

View File

@ -565,6 +565,7 @@ static int load_flat_file(struct linux_binprm *bprm,
/* OK, This is the point of no return */
set_personality(PER_LINUX_32BIT);
setup_new_exec(bprm);
install_exec_creds(bprm);
}
/*
@ -992,8 +993,6 @@ static int load_flat_binary(struct linux_binprm *bprm)
}
}
install_exec_creds(bprm);
set_binfmt(&flat_format);
#ifdef CONFIG_MMU