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exec: cleanup the error handling in search_binary_handler()

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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>
This commit is contained in:
Oleg Nesterov 2013-09-11 14:24:46 -07:00 committed by Linus Torvalds
parent 4e0621a07e
commit 6b3c538f5b
1 changed files with 3 additions and 8 deletions
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11
fs/exec.c
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@ -1399,22 +1399,17 @@ int search_binary_handler(struct linux_binprm *bprm)
bprm->recursion_depth++; bprm->recursion_depth++;
retval = fmt->load_binary(bprm); retval = fmt->load_binary(bprm);
bprm->recursion_depth--; bprm->recursion_depth--;
if (retval >= 0) { if (retval >= 0 || retval != -ENOEXEC ||
bprm->mm == NULL || bprm->file == NULL) {
put_binfmt(fmt); put_binfmt(fmt);
return retval; return retval;
} }
read_lock(&binfmt_lock); read_lock(&binfmt_lock);
put_binfmt(fmt); put_binfmt(fmt);
if (retval != -ENOEXEC || bprm->mm == NULL)
break;
if (!bprm->file) {
read_unlock(&binfmt_lock);
return retval;
}
} }
read_unlock(&binfmt_lock); 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]) && if (printable(bprm->buf[0]) && printable(bprm->buf[1]) &&
printable(bprm->buf[2]) && printable(bprm->buf[3])) printable(bprm->buf[2]) && printable(bprm->buf[3]))
return retval; return retval;