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authorOleg Nesterov <oleg@redhat.com>2013-09-11 14:24:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-11 15:59:05 -0700
commitcb7b6b1cbc20a970c7124efae1c2478155604b54 (patch)
treeef0e867017f0a6fea23ebdcd87753174a4c75a25 /fs/exec.c
parent92eaa565add62d56b90987f58ea9feafc5a7c183 (diff)
downloadlinux-cb7b6b1cbc20a970c7124efae1c2478155604b54.tar.gz
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@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>
Diffstat (limited to 'fs/exec.c')
-rw-r--r--fs/exec.c68
1 files changed, 31 insertions, 37 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 7b92fbfa63a..ba357e6aea9 100644
--- a/fs/exec.c
+++ b/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_binprm *bprm)
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);