binfmt_misc: fix shift-out-of-bounds in check_special_flags

UBSAN reported a shift-out-of-bounds warning:

 left shift of 1 by 31 places cannot be represented in type 'int'
 Call Trace:
  <TASK>
  __dump_stack lib/dump_stack.c:88 [inline]
  dump_stack_lvl+0x8d/0xcf lib/dump_stack.c:106
  ubsan_epilogue+0xa/0x44 lib/ubsan.c:151
  __ubsan_handle_shift_out_of_bounds+0x1e7/0x208 lib/ubsan.c:322
  check_special_flags fs/binfmt_misc.c:241 [inline]
  create_entry fs/binfmt_misc.c:456 [inline]
  bm_register_write+0x9d3/0xa20 fs/binfmt_misc.c:654
  vfs_write+0x11e/0x580 fs/read_write.c:582
  ksys_write+0xcf/0x120 fs/read_write.c:637
  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
  do_syscall_64+0x34/0x80 arch/x86/entry/common.c:80
  entry_SYSCALL_64_after_hwframe+0x63/0xcd
 RIP: 0033:0x4194e1

Since the type of Node's flags is unsigned long, we should define these
macros with same type too.

Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221102025123.1117184-1-liushixin2@huawei.com

diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index e1eae7ea823aeb2d5d0b245511658fcdb3a3ed09..bb202ad369d534859843a01c34d87733b8482467 100644 (file)
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -44,10 +44,10 @@ static LIST_HEAD(entries);
 static int enabled = 1;
 
 enum {Enabled, Magic};
-#define MISC_FMT_PRESERVE_ARGV0 (1 << 31)
-#define MISC_FMT_OPEN_BINARY (1 << 30)
-#define MISC_FMT_CREDENTIALS (1 << 29)
-#define MISC_FMT_OPEN_FILE (1 << 28)
+#define MISC_FMT_PRESERVE_ARGV0 (1UL << 31)
+#define MISC_FMT_OPEN_BINARY (1UL << 30)
+#define MISC_FMT_CREDENTIALS (1UL << 29)
+#define MISC_FMT_OPEN_FILE (1UL << 28)
 
 typedef struct {
        struct list_head list;