• Dmitry Kasatkin's avatar
    ima: check xattr value length and type in the ima_inode_setxattr() · a48fda9d
    Dmitry Kasatkin authored
    ima_inode_setxattr() can be called with no value. Function does not
    check the length so that following command can be used to produce
    kernel oops: setfattr -n security.ima FOO. This patch fixes it.
    
    Changes in v3:
    * for stable reverted "allow setting hash only in fix or log mode"
      It will be a separate patch.
    
    Changes in v2:
    * testing validity of xattr type
    * allow setting hash only in fix or log mode (Mimi)
    
    [  261.562522] BUG: unable to handle kernel NULL pointer dereference at           (null)
    [  261.564109] IP: [<ffffffff812af272>] ima_inode_setxattr+0x3e/0x5a
    [  261.564109] PGD 3112f067 PUD 42965067 PMD 0
    [  261.564109] Oops: 0000 [#1] SMP
    [  261.564109] Modules linked in: bridge stp llc evdev serio_raw i2c_piix4 button fuse
    [  261.564109] CPU: 0 PID: 3299 Comm: setxattr Not tainted 3.16.0-kds+ #2924
    [  261.564109] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
    [  261.564109] task: ffff8800428c2430 ti: ffff880042be0000 task.ti: ffff880042be0000
    [  261.564109] RIP: 0010:[<ffffffff812af272>]  [<ffffffff812af272>] ima_inode_setxattr+0x3e/0x5a
    [  261.564109] RSP: 0018:ffff880042be3d50  EFLAGS: 00010246
    [  261.564109] RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000015
    [  261.564109] RDX: 0000001500000000 RSI: 0000000000000000 RDI: ffff8800375cc600
    [  261.564109] RBP: ffff880042be3d68 R08: 0000000000000000 R09: 00000000004d6256
    [  261.564109] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88002149ba00
    [  261.564109] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
    [  261.564109] FS:  00007f6c1e219740(0000) GS:ffff88005da00000(0000) knlGS:0000000000000000
    [  261.564109] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    [  261.564109] CR2: 0000000000000000 CR3: 000000003b35a000 CR4: 00000000000006f0
    [  261.564109] Stack:
    [  261.564109]  ffff88002149ba00 ffff880042be3df8 0000000000000000 ffff880042be3d98
    [  261.564109]  ffffffff812a101b ffff88002149ba00 ffff880042be3df8 0000000000000000
    [  261.564109]  0000000000000000 ffff880042be3de0 ffffffff8116d08a ffff880042be3dc8
    [  261.564109] Call Trace:
    [  261.564109]  [<ffffffff812a101b>] security_inode_setxattr+0x48/0x6a
    [  261.564109]  [<ffffffff8116d08a>] vfs_setxattr+0x6b/0x9f
    [  261.564109]  [<ffffffff8116d1e0>] setxattr+0x122/0x16c
    [  261.564109]  [<ffffffff811687e8>] ? mnt_want_write+0x21/0x45
    [  261.564109]  [<ffffffff8114d011>] ? __sb_start_write+0x10f/0x143
    [  261.564109]  [<ffffffff811687e8>] ? mnt_want_write+0x21/0x45
    [  261.564109]  [<ffffffff811687c0>] ? __mnt_want_write+0x48/0x4f
    [  261.564109]  [<ffffffff8116d3e6>] SyS_setxattr+0x6e/0xb0
    [  261.564109]  [<ffffffff81529da9>] system_call_fastpath+0x16/0x1b
    [  261.564109] Code: 48 89 f7 48 c7 c6 58 36 81 81 53 31 db e8 73 27 04 00 85 c0 75 28 bf 15 00 00 00 e8 8a a5 d9 ff 84 c0 75 05 83 cb ff eb 15 31 f6 <41> 80 7d 00 03 49 8b 7c 24 68 40 0f 94 c6 e8 e1 f9 ff ff 89 d8
    [  261.564109] RIP  [<ffffffff812af272>] ima_inode_setxattr+0x3e/0x5a
    [  261.564109]  RSP <ffff880042be3d50>
    [  261.564109] CR2: 0000000000000000
    [  261.599998] ---[ end trace 39a89a3fc267e652 ]---
    Reported-by: default avatarJan Kara <jack@suse.cz>
    Signed-off-by: default avatarDmitry Kasatkin <d.kasatkin@samsung.com>
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarMimi Zohar <zohar@linux.vnet.ibm.com>
    a48fda9d
ima_appraise.c 9.71 KB