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Subject[PATCH 5/5] 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>
---
fs/exec.c | 11 +++--------
1 files changed, 3 insertions(+), 8 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index d9fd32c..7ab2120 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -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;
--
1.5.5.1


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