• ChenXiaoSong's avatar
    ntfs: fix use-after-free in ntfs_ucsncmp() · 38c9c22a
    ChenXiaoSong authored
    Syzkaller reported use-after-free bug as follows:
    
    ==================================================================
    BUG: KASAN: use-after-free in ntfs_ucsncmp+0x123/0x130
    Read of size 2 at addr ffff8880751acee8 by task a.out/879
    
    CPU: 7 PID: 879 Comm: a.out Not tainted 5.19.0-rc4-next-20220630-00001-gcc5218c8bd2c-dirty #7
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
    Call Trace:
     <TASK>
     dump_stack_lvl+0x1c0/0x2b0
     print_address_description.constprop.0.cold+0xd4/0x484
     print_report.cold+0x55/0x232
     kasan_report+0xbf/0xf0
     ntfs_ucsncmp+0x123/0x130
     ntfs_are_names_equal.cold+0x2b/0x41
     ntfs_attr_find+0x43b/0xb90
     ntfs_attr_lookup+0x16d/0x1e0
     ntfs_read_locked_attr_inode+0x4aa/0x2360
     ntfs_attr_iget+0x1af/0x220
     ntfs_read_locked_inode+0x246c/0x5120
     ntfs_iget+0x132/0x180
     load_system_files+0x1cc6/0x3480
     ntfs_fill_super+0xa66/0x1cf0
     mount_bdev+0x38d/0x460
     legacy_get_tree+0x10d/0x220
     vfs_get_tree+0x93/0x300
     do_new_mount+0x2da/0x6d0
     path_mount+0x496/0x19d0
     __x64_sys_mount+0x284/0x300
     do_syscall_64+0x3b/0xc0
     entry_SYSCALL_64_after_hwframe+0x46/0xb0
    RIP: 0033:0x7f3f2118d9ea
    Code: 48 8b 0d a9 f4 0b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 76 f4 0b 00 f7 d8 64 89 01 48
    RSP: 002b:00007ffc269deac8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
    RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3f2118d9ea
    RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffc269dec00
    RBP: 00007ffc269dec80 R08: 00007ffc269deb00 R09: 00007ffc269dec44
    R10: 0000000000000000 R11: 0000000000000202 R12: 000055f81ab1d220
    R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
     </TASK>
    
    The buggy address belongs to the physical page:
    page:0000000085430378 refcount:1 mapcount:1 mapping:0000000000000000 index:0x555c6a81d pfn:0x751ac
    memcg:ffff888101f7e180
    anon flags: 0xfffffc00a0014(uptodate|lru|mappedtodisk|swapbacked|node=0|zone=1|lastcpupid=0x1fffff)
    raw: 000fffffc00a0014 ffffea0001bf2988 ffffea0001de2448 ffff88801712e201
    raw: 0000000555c6a81d 0000000000000000 0000000100000000 ffff888101f7e180
    page dumped because: kasan: bad access detected
    
    Memory state around the buggy address:
     ffff8880751acd80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
     ffff8880751ace00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    >ffff8880751ace80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                                              ^
     ffff8880751acf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
     ffff8880751acf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    ==================================================================
    
    The reason is that struct ATTR_RECORD->name_offset is 6485, end address of
    name string is out of bounds.
    
    Fix this by adding sanity check on end address of attribute name string.
    
    [akpm@linux-foundation.org: coding-style cleanups]
    [chenxiaosong2@huawei.com: cleanup suggested by Hawkins Jiawei]
      Link: https://lkml.kernel.org/r/20220709064511.3304299-1-chenxiaosong2@huawei.com
    Link: https://lkml.kernel.org/r/20220707105329.4020708-1-chenxiaosong2@huawei.comSigned-off-by: default avatarChenXiaoSong <chenxiaosong2@huawei.com>
    Signed-off-by: default avatarHawkins Jiawei <yin31149@gmail.com>
    Cc: Anton Altaparmakov <anton@tuxera.com>
    Cc: ChenXiaoSong <chenxiaosong2@huawei.com>
    Cc: Yongqiang Liu <liuyongqiang13@huawei.com>
    Cc: Zhang Yi <yi.zhang@huawei.com>
    Cc: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    38c9c22a
attrib.c 89 KB