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From: Mimi Zohar <zohar@linux.ibm.com>
To: Roberto Sassu <roberto.sassu@huawei.com>, tiwai@suse.de
Cc: linux-integrity@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org, silviu.vlasceanu@huawei.com,
	stable@vger.kernel.org
Subject: Re: [PATCH 1/2] ima: Directly assign the ima_default_policy pointer to ima_rules
Date: Wed, 03 Jun 2020 17:30:22 -0400	[thread overview]
Message-ID: <1591219822.5146.2.camel@linux.ibm.com> (raw)
In-Reply-To: <20200603150821.8607-1-roberto.sassu@huawei.com>

On Wed, 2020-06-03 at 17:08 +0200, Roberto Sassu wrote:
> This patch prevents the following oops:
> 
> [   10.771813] BUG: kernel NULL pointer dereference, address: 0000000000000
> [...]
> [   10.779790] RIP: 0010:ima_match_policy+0xf7/0xb80
> [...]
> [   10.798576] Call Trace:
> [   10.798993]  ? ima_lsm_policy_change+0x2b0/0x2b0
> [   10.799753]  ? inode_init_owner+0x1a0/0x1a0
> [   10.800484]  ? _raw_spin_lock+0x7a/0xd0
> [   10.801592]  ima_must_appraise.part.0+0xb6/0xf0
> [   10.802313]  ? ima_fix_xattr.isra.0+0xd0/0xd0
> [   10.803167]  ima_must_appraise+0x4f/0x70
> [   10.804004]  ima_post_path_mknod+0x2e/0x80
> [   10.804800]  do_mknodat+0x396/0x3c0
> 
> It occurs when there is a failure during IMA initialization, and
> ima_init_policy() is not called. IMA hooks still call ima_match_policy()
> but ima_rules is NULL. This patch prevents the crash by directly assigning
> the ima_default_policy pointer to ima_rules when ima_rules is defined. This
> wouldn't alter the existing behavior, as ima_rules is always set at the end
> of ima_init_policy().
> 
> Cc: stable@vger.kernel.org # 3.7.x
> Fixes: 07f6a79415d7d ("ima: add appraise action keywords and default rules")
> Reported-by: Takashi Iwai <tiwai@suse.de>
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>

Thanks, Roberto!

  parent reply	other threads:[~2020-06-03 21:30 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-03 15:08 [PATCH 1/2] ima: Directly assign the ima_default_policy pointer to ima_rules Roberto Sassu
2020-06-03 15:08 ` [PATCH 2/2] ima: Call ima_calc_boot_aggregate() in ima_eventdigest_init() Roberto Sassu
2020-06-03 22:03   ` Mimi Zohar
2020-06-04 19:12     ` Bruno Meneguele
2020-06-04 19:35       ` Mimi Zohar
2020-06-04 19:57         ` Bruno Meneguele
2020-06-05 14:10   ` Sasha Levin
2020-06-03 21:30 ` Mimi Zohar [this message]
2020-06-05 14:10 ` [PATCH 1/2] ima: Directly assign the ima_default_policy pointer to ima_rules Sasha Levin

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