• Ye Bin's avatar
    fs/ntfs3: Fix NULL pointer dereference in 'ni_write_inode' · db2a3cc6
    Ye Bin authored
    Syzbot found the following issue:
    Unable to handle kernel NULL pointer dereference at virtual address 0000000000000016
    Mem abort info:
      ESR = 0x0000000096000006
      EC = 0x25: DABT (current EL), IL = 32 bits
      SET = 0, FnV = 0
      EA = 0, S1PTW = 0
      FSC = 0x06: level 2 translation fault
    Data abort info:
      ISV = 0, ISS = 0x00000006
      CM = 0, WnR = 0
    user pgtable: 4k pages, 48-bit VAs, pgdp=000000010af56000
    [0000000000000016] pgd=08000001090da003, p4d=08000001090da003, pud=08000001090ce003, pmd=0000000000000000
    Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
    Modules linked in:
    CPU: 1 PID: 3036 Comm: syz-executor206 Not tainted 6.0.0-rc6-syzkaller-17739-g16c9f284e746 #0
    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
    pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
    pc : is_rec_inuse fs/ntfs3/ntfs.h:313 [inline]
    pc : ni_write_inode+0xac/0x798 fs/ntfs3/frecord.c:3232
    lr : ni_write_inode+0xa0/0x798 fs/ntfs3/frecord.c:3226
    sp : ffff8000126c3800
    x29: ffff8000126c3860 x28: 0000000000000000 x27: ffff0000c8b02000
    x26: ffff0000c7502320 x25: ffff0000c7502288 x24: 0000000000000000
    x23: ffff80000cbec91c x22: ffff0000c8b03000 x21: ffff0000c8b02000
    x20: 0000000000000001 x19: ffff0000c75024d8 x18: 00000000000000c0
    x17: ffff80000dd1b198 x16: ffff80000db59158 x15: ffff0000c4b6b500
    x14: 00000000000000b8 x13: 0000000000000000 x12: ffff0000c4b6b500
    x11: ff80800008be1b60 x10: 0000000000000000 x9 : ffff0000c4b6b500
    x8 : 0000000000000000 x7 : ffff800008be1b50 x6 : 0000000000000000
    x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000
    x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
    Call trace:
     is_rec_inuse fs/ntfs3/ntfs.h:313 [inline]
     ni_write_inode+0xac/0x798 fs/ntfs3/frecord.c:3232
     ntfs_evict_inode+0x54/0x84 fs/ntfs3/inode.c:1744
     evict+0xec/0x334 fs/inode.c:665
     iput_final fs/inode.c:1748 [inline]
     iput+0x2c4/0x324 fs/inode.c:1774
     ntfs_new_inode+0x7c/0xe0 fs/ntfs3/fsntfs.c:1660
     ntfs_create_inode+0x20c/0xe78 fs/ntfs3/inode.c:1278
     ntfs_create+0x54/0x74 fs/ntfs3/namei.c:100
     lookup_open fs/namei.c:3413 [inline]
     open_last_lookups fs/namei.c:3481 [inline]
     path_openat+0x804/0x11c4 fs/namei.c:3688
     do_filp_open+0xdc/0x1b8 fs/namei.c:3718
     do_sys_openat2+0xb8/0x22c fs/open.c:1311
     do_sys_open fs/open.c:1327 [inline]
     __do_sys_openat fs/open.c:1343 [inline]
     __se_sys_openat fs/open.c:1338 [inline]
     __arm64_sys_openat+0xb0/0xe0 fs/open.c:1338
     __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
     invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
     el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
     do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
     el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:636
     el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:654
     el0t_64_sync+0x18c/0x190
    Code: 97dafee4 340001b4 f9401328 2a1f03e0 (79402d14)
    ---[ end trace 0000000000000000 ]---
    
    Above issue may happens as follows:
    ntfs_new_inode
      mi_init
        mi->mrec = kmalloc(sbi->record_size, GFP_NOFS); -->failed to allocate memory
          if (!mi->mrec)
            return -ENOMEM;
    iput
      iput_final
        evict
          ntfs_evict_inode
            ni_write_inode
    	  is_rec_inuse(ni->mi.mrec)-> As 'ni->mi.mrec' is NULL trigger NULL-ptr-deref
    
    To solve above issue if new inode failed make inode bad before call 'iput()' in
    'ntfs_new_inode()'.
    
    Reported-by: syzbot+f45957555ed4a808cc7a@syzkaller.appspotmail.com
    Signed-off-by: default avatarYe Bin <yebin10@huawei.com>
    Signed-off-by: default avatarKonstantin Komarov <almaz.alexandrovich@paragon-software.com>
    db2a3cc6
fsntfs.c 55.6 KB