Dmitry Kasatkin bcaf8f4d1a evm: check xattr value length and type in evm_inode_setxattr() ... 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: Jan Kara <jack@suse.cz> Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2014-11-14 08:47:54 -08:00
..
evm	evm: check xattr value length and type in evm_inode_setxattr()	2014-11-14 08:47:54 -08:00
ima	ima: introduce ima_kernel_read()	2014-06-26 15:12:37 -04:00
digsig.c	ima: digital signature verification using asymmetric keys	2013-02-06 21:22:18 -05:00
digsig_asymmetric.c	ima: digital signature verification using asymmetric keys	2013-02-06 21:22:18 -05:00
iint.c	ima: per hook cache integrity appraisal status	2013-01-22 16:10:36 -05:00
integrity.h	ima: digital signature verification using asymmetric keys	2013-02-06 21:22:18 -05:00
Kconfig	ima: digital signature verification using asymmetric keys	2013-02-06 21:22:18 -05:00
Makefile	ima: digital signature verification using asymmetric keys	2013-02-06 21:22:18 -05:00