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Commit b8383831 authored by Kees Cook's avatar Kees Cook Committed by Linus Torvalds
Browse files

exec: introduce finalize_exec() before start_thread() 

Provide a final callback into fs/exec.c before start_thread() takes
over, to handle any last-minute changes, like the coming restoration of
the stack limit.

Link: http://lkml.kernel.org/r/1518638796-20819-3-git-send-email-keescook@chromium.org


Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: Greg KH <greg@kroah.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8f2af155

fs/binfmt_aout.c

+1 −0
Original line number Diff line number Diff line
@@ -330,6 +330,7 @@ static int load_aout_binary(struct linux_binprm * bprm) 
#ifdef __alpha__

	regs->gp = ex.a_gpvalue;

#endif

	finalize_exec(bprm);

	start_thread(regs, ex.a_entry, current->mm->start_stack);

	return 0;

}

fs/binfmt_elf.c

+1 −0
Original line number Diff line number Diff line
@@ -1155,6 +1155,7 @@ static int load_elf_binary(struct linux_binprm *bprm) 
	ELF_PLAT_INIT(regs, reloc_func_desc);

#endif



	finalize_exec(bprm);

	start_thread(regs, elf_entry, bprm->p);

	retval = 0;

out:

fs/binfmt_elf_fdpic.c

+1 −0
Original line number Diff line number Diff line
@@ -463,6 +463,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm) 
			    dynaddr);

#endif



	finalize_exec(bprm);

	/* everything is now ready... get the userspace context ready to roll */

	entryaddr = interp_params.entry_addr ?: exec_params.entry_addr;

	start_thread(regs, entryaddr, current->mm->start_stack);

fs/binfmt_flat.c

+1 −0
Original line number Diff line number Diff line
@@ -994,6 +994,7 @@ static int load_flat_binary(struct linux_binprm *bprm) 
	FLAT_PLAT_INIT(regs);

#endif



	finalize_exec(bprm);

	pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n",

		 regs, start_addr, current->mm->start_stack);

	start_thread(regs, start_addr, current->mm->start_stack);

fs/exec.c

+6 −0
Original line number Diff line number Diff line
@@ -1384,6 +1384,12 @@ void setup_new_exec(struct linux_binprm * bprm) 
}

EXPORT_SYMBOL(setup_new_exec);



/* Runs immediately before start_thread() takes over. */

void finalize_exec(struct linux_binprm *bprm)

{

}

EXPORT_SYMBOL(finalize_exec);



/*

 * Prepare credentials and lock ->cred_guard_mutex.

 * install_exec_creds() commits the new creds and drops the lock.