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Commit 52f14282 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

exec: move allow_write_access/fput to exec_binprm() 



When search_binary_handler() succeeds it does allow_write_access() and
fput(), then it clears bprm->file to ensure the caller will not do the
same.

We can simply move this code to exec_binprm() which is called only once.
In fact we could move this to free_bprm() and remove the same code in
do_execve_common's error path.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9beb266f

fs/exec.c

+6 −4
Original line number Original line Diff line number Diff line
@@ -1400,10 +1400,6 @@ int search_binary_handler(struct linux_binprm *bprm) 
			bprm->recursion_depth--;

			bprm->recursion_depth--;

			if (retval >= 0) {

			if (retval >= 0) {

				put_binfmt(fmt);

				put_binfmt(fmt);

				allow_write_access(bprm->file);

				if (bprm->file)

					fput(bprm->file);

				bprm->file = NULL;

				return retval;

				return retval;

			}

			}

			read_lock(&binfmt_lock);

			read_lock(&binfmt_lock);
@@ -1455,6 +1451,12 @@ static int exec_binprm(struct linux_binprm *bprm) 
		ptrace_event(PTRACE_EVENT_EXEC, old_vpid);

		ptrace_event(PTRACE_EVENT_EXEC, old_vpid);

		current->did_exec = 1;

		current->did_exec = 1;

		proc_exec_connector(current);

		proc_exec_connector(current);



		if (bprm->file) {

			allow_write_access(bprm->file);

			fput(bprm->file);

			bprm->file = NULL; /* to catch use-after-free */

		}

	}

	}





	return ret;

	return ret;