binfmt: Move install_exec_creds after setup_new_exec to match binfmt_elf

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: 9f834ec18def ("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>

diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c
index 9bb71abd66bd33f273903f8811e3f4ce59296be7..37b36a8ce5fa74ab87c1baa43b50fa55c7e0199a 100644 (file)
--- a/arch/x86/ia32/ia32_aout.c
+++ b/arch/x86/ia32/ia32_aout.c
@@ -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;
 

diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c
index 8e8346a81723c4ec43bd36802fb80b8080fe4234..ace587b66904c855d519fe97d3afdb969b8dc223 100644 (file)
--- a/fs/binfmt_aout.c
+++ b/fs/binfmt_aout.c
@@ -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;

diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 240f6666354377a8ea818df0299d8d1f5200fa52..6c94c6d53d971a852fa6510b89748cc1b4c8fd6d 100644 (file)
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -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;

diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index 831a2b25ba79f1cf39cab68316060e1ef02396c0..1a1d1fcb893f1b0e1df4311cd7eab1a3bc82a541 100644 (file)
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -541,6 +541,7 @@ 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);
        }
 
        /*
@@ -963,8 +964,6 @@ static int load_flat_binary(struct linux_binprm *bprm)
                }
        }
 
-       install_exec_creds(bprm);
-
        set_binfmt(&flat_format);
 
 #ifdef CONFIG_MMU