Commit 6b3c538f authored Sep 11, 2013 by Oleg Nesterov Committed by Linus Torvalds Sep 11, 2013

exec: cleanup the error handling in search_binary_handler()



The error hanling and ret-from-loop look confusing and inconsistent.

- "retval >= 0" simply returns

- "!bprm->file" returns too but with read_unlock() because
   binfmt_lock was already re-acquired

- "retval != -ENOEXEC || bprm->mm == NULL" does "break" and
  relies on the same check after the main loop

Consolidate these checks into a single if/return statement.

need_retry still checks "retval == -ENOEXEC", but this and -ENOENT before
the main loop are not needed.  This is only for pathological and
impossible list_empty(&formats) case.

It is not clear why do we check "bprm->mm == NULL", probably this
should be removed.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 4e0621a0

fs/exec.c

+3 −8

Original line number	Diff line number	Diff line
		@@ -1399,22 +1399,17 @@ int search_binary_handler(struct linux_binprm *bprm)
		bprm->recursion_depth++;
		retval = fmt->load_binary(bprm);
		bprm->recursion_depth--;
		if (retval >= 0) {
		if (retval >= 0 \|\| retval != -ENOEXEC \|\|
		bprm->mm == NULL \|\| bprm->file == NULL) {
		put_binfmt(fmt);
		return retval;
		}
		read_lock(&binfmt_lock);
		put_binfmt(fmt);
		if (retval != -ENOEXEC \|\| bprm->mm == NULL)
		break;
		if (!bprm->file) {
		read_unlock(&binfmt_lock);
		return retval;
		}
		}
		read_unlock(&binfmt_lock);

		if (need_retry && retval == -ENOEXEC && bprm->mm) {
		if (need_retry && retval == -ENOEXEC) {
		if (printable(bprm->buf[0]) && printable(bprm->buf[1]) &&
		printable(bprm->buf[2]) && printable(bprm->buf[3]))
		return retval;

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