Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756595AbaDWNiA (ORCPT ); Wed, 23 Apr 2014 09:38:00 -0400 Received: from mailout3.w1.samsung.com ([210.118.77.13]:56873 "EHLO mailout3.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756125AbaDWN37 (ORCPT ); Wed, 23 Apr 2014 09:29:59 -0400 X-AuditID: cbfec7f4-b7fb36d000006ff7-9c-5357c056793b From: Dmitry Kasatkin To: zohar@linux.vnet.ibm.com, dhowells@redhat.com, jmorris@namei.org Cc: roberto.sassu@polito.it, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Dmitry Kasatkin Subject: [PATCH 18/20] evm: added kernel parameter for disabling EVM Date: Wed, 23 Apr 2014 16:30:36 +0300 Message-id: <8382d218eb0debfff621f9561156aa56cee5f88d.1398259638.git.d.kasatkin@samsung.com> X-Mailer: git-send-email 1.8.3.2 In-reply-to: References: In-reply-to: References: X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprELMWRmVeSWpSXmKPExsVy+t/xq7phB8KDDX62MVrc+ruX2eJd028W i3XrFzNZXN41h83iQ88jNouXu76xW3xaMYnZgd3jwaHNLB4935M9Tq8s9ni/7yqbR9+WVYwe nzfJBbBFcdmkpOZklqUW6dslcGVc2biGteCWWMWP5vtMDYz3hboYOTkkBEwkVl9/yQZhi0lc uLceyObiEBJYyihx7NxaJgink0nic9N5dpAqNgE9iQ3NP8BsEQEXid1z+sCKmAV6GCV2/1nM DJIQBkr0Na5kAbFZBFQlNh26wgpi8wrESew71cEEsU5BYtmXtWD1nAJWEn+ap4MNFRKwlPg+ aTJO8QmM/AsYGVYxiqaWJhcUJ6XnGuoVJ+YWl+al6yXn525ihITjlx2Mi49ZHWIU4GBU4uGV WB4WLMSaWFZcmXuIUYKDWUmEd8mi8GAh3pTEyqrUovz4otKc1OJDjEwcnFINjOyXz21W3WSX cuX6Xr8Zf3bM6b7YmynQo+BQ6H/F/NID4UeTV69v3Od8MNye+cmJB+K+PLnrFue9iI6fybdv yWqvHBlXxlcMj200o+Wvyx1ySuztkt7OnHv98tw2oTtlrC/Ctu3mW2QZ6XrHScbCNKmzbl/r vsOHnfh7r37YVCE84RnvUsvbykosxRmJhlrMRcWJAMF5MfwlAgAA Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org EVM remained to be disabled until evm-key is initialized via sysfs. When the key is loaded from the kernel, EVM becomes enabled from start. Distributions might want to compile EVM support, but leave for the user to decide if to enable or disable EVM functionality. This patch provides kernel parameter 'evm=off' that allows to disable EVM. Signed-off-by: Dmitry Kasatkin --- security/integrity/evm/evm.h | 5 +++++ security/integrity/evm/evm_main.c | 19 +++++++++++++------ security/integrity/evm/evm_secfs.c | 3 ++- 3 files changed, 20 insertions(+), 7 deletions(-) diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h index 88bfe77..1db78b8 100644 --- a/security/integrity/evm/evm.h +++ b/security/integrity/evm/evm.h @@ -21,6 +21,11 @@ #include "../integrity.h" +#define EVM_MODE_OFF 0 +#define EVM_MODE_ON 1 +#define EVM_MODE_FIX 2 + +extern int evm_mode; extern int evm_initialized; extern char *evm_hmac; extern char *evm_hash; diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 0f1b489..ad5e641 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -53,14 +53,17 @@ char *evm_config_xattrnames[] = { NULL }; -static int evm_fixmode; -static int __init evm_set_fixmode(char *str) +int evm_mode = EVM_MODE_ON; + +static int __init evm_setup(char *str) { - if (strncmp(str, "fix", 3) == 0) - evm_fixmode = 1; + if (strncmp(str, "off", 3) == 0) + evm_mode = EVM_MODE_OFF; + else if (strncmp(str, "fix", 3) == 0) + evm_mode = EVM_MODE_FIX; return 0; } -__setup("evm=", evm_set_fixmode); +__setup("evm=", evm_setup); static void __init evm_init_config(void) { @@ -249,7 +252,8 @@ static enum integrity_status evm_verify_current_integrity(struct dentry *dentry) { struct inode *inode = dentry->d_inode; - if (!evm_initialized || !S_ISREG(inode->i_mode) || evm_fixmode) + if (!evm_initialized || !S_ISREG(inode->i_mode) || + evm_mode == EVM_MODE_FIX) return 0; return evm_verify_hmac(dentry, NULL, NULL, 0, NULL); } @@ -445,6 +449,9 @@ static int __init init_evm(void) { int error; + if (evm_mode == EVM_MODE_OFF) + return 0; + evm_init_config(); integrity_init_keyring(INTEGRITY_KEYRING_EVM); diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c index cf12a04..4c81ef6 100644 --- a/security/integrity/evm/evm_secfs.c +++ b/security/integrity/evm/evm_secfs.c @@ -64,7 +64,8 @@ static ssize_t evm_write_key(struct file *file, const char __user *buf, char temp[80]; int i, error; - if (!capable(CAP_SYS_ADMIN) || evm_initialized) + if (!capable(CAP_SYS_ADMIN) || evm_initialized || + evm_mode == EVM_MODE_OFF) return -EPERM; if (count >= sizeof(temp) || count == 0) -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/