• Dmitry Kasatkin's avatar
    evm: check xattr value length and type in evm_inode_setxattr() · bcaf8f4d
    Dmitry Kasatkin authored
    commit 3b1deef6b1289a99505858a3b212c5b50adf0c2f upstream.
    
    evm_inode_setxattr() can be called with no value. The function does not
    check the length so that following command can be used to produce the
    kernel oops: setfattr -n security.evm FOO. This patch fixes it.
    
    Changes in v3:
    * there is no reason to return different error codes for EVM_XATTR_HMAC
      and non EVM_XATTR_HMAC. Remove unnecessary test then.
    
    Changes in v2:
    * testing for validity of xattr type
    
    [ 1106.396921] BUG: unable to handle kernel NULL pointer dereference at           (null)
    [ 1106.398192] IP: [<ffffffff812af7b8>] evm_inode_setxattr+0x2a/0x48
    [ 1106.399244] PGD 29048067 PUD 290d7067 PMD 0
    [ 1106.399953] Oops: 0000 [#1] SMP
    [ 1106.400020] Modules linked in: bridge stp llc evdev serio_raw i2c_piix4 button fuse
    [ 1106.400020] CPU: 0 PID: 3635 Comm: setxattr Not tainted 3.16.0-kds+ #2936
    [ 1106.400020] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
    [ 1106.400020] task: ffff8800291a0000 ti: ffff88002917c000 task.ti: ffff88002917c000
    [ 1106.400020] RIP: 0010:[<ffffffff812af7b8>]  [<ffffffff812af7b8>] evm_inode_setxattr+0x2a/0x48
    [ 1106.400020] RSP: 0018:ffff88002917fd50  EFLAGS: 00010246
    [ 1106.400020] RAX: 0000000000000000 RBX: ffff88002917fdf8 RCX: 0000000000000000
    [ 1106.400020] RDX: 0000000000000000 RSI: ffffffff818136d3 RDI: ffff88002917fdf8
    [ 1106.400020] RBP: ffff88002917fd68 R08: 0000000000000000 R09: 00000000003ec1df
    [ 1106.400020] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800438a0a00
    [ 1106.400020] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
    [ 1106.400020] FS:  00007f7dfa7d7740(0000) GS:ffff88005da00000(0000) knlGS:0000000000000000
    [ 1106.400020] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    [ 1106.400020] CR2: 0000000000000000 CR3: 000000003763e000 CR4: 00000000000006f0
    [ 1106.400020] Stack:
    [ 1106.400020]  ffff8800438a0a00 ffff88002917fdf8 0000000000000000 ffff88002917fd98
    [ 1106.400020]  ffffffff812a1030 ffff8800438a0a00 ffff88002917fdf8 0000000000000000
    [ 1106.400020]  0000000000000000 ffff88002917fde0 ffffffff8116d08a ffff88002917fdc8
    [ 1106.400020] Call Trace:
    [ 1106.400020]  [<ffffffff812a1030>] security_inode_setxattr+0x5d/0x6a
    [ 1106.400020]  [<ffffffff8116d08a>] vfs_setxattr+0x6b/0x9f
    [ 1106.400020]  [<ffffffff8116d1e0>] setxattr+0x122/0x16c
    [ 1106.400020]  [<ffffffff811687e8>] ? mnt_want_write+0x21/0x45
    [ 1106.400020]  [<ffffffff8114d011>] ? __sb_start_write+0x10f/0x143
    [ 1106.400020]  [<ffffffff811687e8>] ? mnt_want_write+0x21/0x45
    [ 1106.400020]  [<ffffffff811687c0>] ? __mnt_want_write+0x48/0x4f
    [ 1106.400020]  [<ffffffff8116d3e6>] SyS_setxattr+0x6e/0xb0
    [ 1106.400020]  [<ffffffff81529da9>] system_call_fastpath+0x16/0x1b
    [ 1106.400020] Code: c3 0f 1f 44 00 00 55 48 89 e5 41 55 49 89 d5 41 54 49 89 fc 53 48 89 f3 48 c7 c6 d3 36 81 81 48 89 df e8 18 22 04 00 85 c0 75 07 <41> 80 7d 00 02 74 0d 48 89 de 4c 89 e7 e8 5a fe ff ff eb 03 83
    [ 1106.400020] RIP  [<ffffffff812af7b8>] evm_inode_setxattr+0x2a/0x48
    [ 1106.400020]  RSP <ffff88002917fd50>
    [ 1106.400020] CR2: 0000000000000000
    [ 1106.428061] ---[ end trace ae08331628ba3050 ]---
    Reported-by: 's avatarJan Kara <jack@suse.cz>
    Signed-off-by: 's avatarDmitry Kasatkin <d.kasatkin@samsung.com>
    Signed-off-by: 's avatarMimi Zohar <zohar@linux.vnet.ibm.com>
    Signed-off-by: 's avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    bcaf8f4d
Name
Last commit
Last update
..
evm Loading commit data...
ima Loading commit data...
Kconfig Loading commit data...
Makefile Loading commit data...
digsig.c Loading commit data...
digsig_asymmetric.c Loading commit data...
iint.c Loading commit data...
integrity.h Loading commit data...