Subject: + exec-cleanup-the-config_modules-logic.patch added to -mm tree
To: oleg@xxxxxxxxxx,keescook@xxxxxxxxxxxx,viro@xxxxxxxxxxxxxxxxxx,zbr@xxxxxxxxxxx,zml@xxxxxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 05 Aug 2013 13:45:13 -0700
The patch titled
Subject: exec: cleanup the CONFIG_MODULES logic
has been added to the -mm tree. Its filename is
exec-cleanup-the-config_modules-logic.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/exec-cleanup-the-config_modules-logic.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/exec-cleanup-the-config_modules-logic.patch
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------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: exec: cleanup the CONFIG_MODULES logic
search_binary_handler() uses "for (try=0; try<2; try++)" to avoid "goto"
but the code looks too complicated and horrible imho. We still need to
check "try == 0" before request_module() and add the additional "break"
for !CONFIG_MODULES case.
Kill this loop and use a simple "bool need_retry" + "goto retry". The
code looks much simpler and we do not even need ifdef's, gcc can optimize
out the "if (need_retry)" block if !IS_ENABLED().
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Evgeniy Polyakov <zbr@xxxxxxxxxxx>
Cc: Zach Levis <zml@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/exec.c | 68 +++++++++++++++++++++++-----------------------------
1 file changed, 31 insertions(+), 37 deletions(-)
diff -puN fs/exec.c~exec-cleanup-the-config_modules-logic fs/exec.c
--- a/fs/exec.c~exec-cleanup-the-config_modules-logic
+++ a/fs/exec.c
@@ -1367,13 +1367,15 @@ out:
}
EXPORT_SYMBOL(remove_arg_zero);
+#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
/*
* cycle the list of binary formats handler, until one recognizes the image
*/
int search_binary_handler(struct linux_binprm *bprm)
{
- int try, retval;
+ bool need_retry = IS_ENABLED(CONFIG_MODULES);
struct linux_binfmt *fmt;
+ int retval;
/* This allows 4 levels of binfmt rewrites before failing hard. */
if (bprm->recursion_depth > 5)
@@ -1388,47 +1390,39 @@ int search_binary_handler(struct linux_b
return retval;
retval = -ENOENT;
- for (try=0; try<2; try++) {
- read_lock(&binfmt_lock);
- list_for_each_entry(fmt, &formats, lh) {
- if (!try_module_get(fmt->module))
- continue;
- read_unlock(&binfmt_lock);
- bprm->recursion_depth++;
- retval = fmt->load_binary(bprm);
- bprm->recursion_depth--;
- if (retval >= 0) {
- put_binfmt(fmt);
- return retval;
- }
- read_lock(&binfmt_lock);
+ retry:
+ read_lock(&binfmt_lock);
+ list_for_each_entry(fmt, &formats, lh) {
+ if (!try_module_get(fmt->module))
+ continue;
+ read_unlock(&binfmt_lock);
+ bprm->recursion_depth++;
+ retval = fmt->load_binary(bprm);
+ bprm->recursion_depth--;
+ if (retval >= 0) {
put_binfmt(fmt);
- if (retval != -ENOEXEC || bprm->mm == NULL)
- break;
- if (!bprm->file) {
- read_unlock(&binfmt_lock);
- return retval;
- }
+ return retval;
}
- read_unlock(&binfmt_lock);
-#ifdef CONFIG_MODULES
- if (retval != -ENOEXEC || bprm->mm == NULL) {
+ read_lock(&binfmt_lock);
+ put_binfmt(fmt);
+ if (retval != -ENOEXEC || bprm->mm == NULL)
break;
- } else {
-#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
- if (printable(bprm->buf[0]) &&
- printable(bprm->buf[1]) &&
- printable(bprm->buf[2]) &&
- printable(bprm->buf[3]))
- break; /* -ENOEXEC */
- if (try)
- break; /* -ENOEXEC */
- request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
+ if (!bprm->file) {
+ read_unlock(&binfmt_lock);
+ return retval;
}
-#else
- break;
-#endif
}
+ read_unlock(&binfmt_lock);
+
+ if (need_retry && retval == -ENOEXEC && bprm->mm) {
+ if (printable(bprm->buf[0]) && printable(bprm->buf[1]) &&
+ printable(bprm->buf[2]) && printable(bprm->buf[3]))
+ return retval;
+ request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2));
+ need_retry = false;
+ goto retry;
+ }
+
return retval;
}
EXPORT_SYMBOL(search_binary_handler);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
x86-get_unmapped_area-use-proper-mmap-base-for-bottom-up-direction.patch
include-linux-schedh-dont-use-task-pid-tgid-in-same_thread_group-has_group_leader_pid.patch
mm-mempolicy-turn-vma_set_policy-into-vma_dup_policy.patch
mm-shift-vm_grows-check-from-mmap_region-to-do_mmap_pgoff-v2.patch
mm-do_mmap_pgoff-cleanup-the-usage-of-file_inode.patch
mm-mmap_region-kill-correct_wcount-inode-use-allow_write_access.patch
kernel-wide-fix-missing-validations-on-__get-__put-__copy_to-__copy_from_user.patch
autofs4-allow-autofs-to-work-outside-the-initial-pid-namespace.patch
autofs4-translate-pids-to-the-right-namespace-for-the-daemon.patch
signals-eventpoll-set-saved_sigmask-at-the-start.patch
move-exit_task_namespaces-outside-of-exit_notify-fix.patch
exec-introduce-exec_binprm-for-depth-==-0-code.patch
exec-kill-int-depth-in-search_binary_handler.patch
exec-proc_exec_connector-should-be-called-only-once.patch
exec-move-allow_write_access-fput-to-exec_binprm.patch
exec-kill-load_binary-=-null-check-in-search_binary_handler.patch
exec-cleanup-the-config_modules-logic.patch
exec-dont-retry-if-request_module-fails.patch
exec-cleanup-the-error-handling-in-search_binary_handler.patch
linux-next.patch
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