exec: unify do_execve/compat_do_execve code

Add the appropriate members into struct user_arg_ptr and teach
get_user_arg_ptr() to handle is_compat = T case correctly.

This allows us to remove the compat_do_execve() code from fs/compat.c
and reimplement compat_do_execve() as the trivial wrapper on top of
do_execve_common(is_compat => true).

In fact, this fixes another (minor) bug. "compat_uptr_t str" can
overflow after "str += len" in compat_copy_strings() if a 64bit
application execs via sys32_execve().

Unexport acct_arg_size() and get_arg_page(), fs/compat.c doesn't
need them any longer.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>

1 files changed, 0 insertions, 4 deletions

diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index c3d6512eded1..8845613fd7e3 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -60,10 +60,6 @@ struct linux_binprm {
         unsigned long loader, exec;
 };
 
-extern void acct_arg_size(struct linux_binprm *bprm, unsigned long pages);
-extern struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
-                                        int write);
-
 #define BINPRM_FLAGS_ENFORCE_NONDUMP_BIT 0
 #define BINPRM_FLAGS_ENFORCE_NONDUMP (1 << BINPRM_FLAGS_ENFORCE_NONDUMP_BIT)