void __register_binfmt(struct linux_binfmt * fmt, int insert)
{
BUG_ON(!fmt);
+ if (WARN_ON(!fmt->load_binary))
+ return;
write_lock(&binfmt_lock);
insert ? list_add(&fmt->lh, &formats) :
list_add_tail(&fmt->lh, &formats);
}
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)
{
- unsigned int depth = bprm->recursion_depth;
- 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 (depth > 5)
+ if (bprm->recursion_depth > 5)
return -ELOOP;
retval = security_bprm_check(bprm);
return retval;
retval = -ENOENT;
- for (try=0; try<2; try++) {
- read_lock(&binfmt_lock);
- list_for_each_entry(fmt, &formats, lh) {
- int (*fn)(struct linux_binprm *) = fmt->load_binary;
- if (!fn)
- continue;
- if (!try_module_get(fmt->module))
- continue;
- read_unlock(&binfmt_lock);
- bprm->recursion_depth = depth + 1;
- retval = fn(bprm);
- bprm->recursion_depth = depth;
- if (retval >= 0) {
- put_binfmt(fmt);
- allow_write_access(bprm->file);
- if (bprm->file)
- fput(bprm->file);
- bprm->file = NULL;
- proc_exec_connector(current);
- 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;
- }
- }
+ retry:
+ read_lock(&binfmt_lock);
+ list_for_each_entry(fmt, &formats, lh) {
+ if (!try_module_get(fmt->module))
+ continue;
read_unlock(&binfmt_lock);
-#ifdef CONFIG_MODULES
- 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]));
+ bprm->recursion_depth++;
+ retval = fmt->load_binary(bprm);
+ bprm->recursion_depth--;
+ if (retval >= 0 || retval != -ENOEXEC ||
+ bprm->mm == NULL || bprm->file == NULL) {
+ put_binfmt(fmt);
+ return retval;
}
-#else
- break;
-#endif
+ read_lock(&binfmt_lock);
+ put_binfmt(fmt);
+ }
+ read_unlock(&binfmt_lock);
+
+ if (need_retry && retval == -ENOEXEC) {
+ if (printable(bprm->buf[0]) && printable(bprm->buf[1]) &&
+ printable(bprm->buf[2]) && printable(bprm->buf[3]))
+ return retval;
+ if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0)
+ return retval;
+ need_retry = false;
+ goto retry;
}
+
return retval;
}
EXPORT_SYMBOL(search_binary_handler);
trace_sched_process_exec(current, old_pid, bprm);
ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
current->did_exec = 1;
+ proc_exec_connector(current);
+
+ if (bprm->file) {
+ allow_write_access(bprm->file);
+ fput(bprm->file);
+ bprm->file = NULL; /* to catch use-after-free */
+ }
}
return ret;