linux-dev/security/integrity/evm, branch linus/master

evm: Clean up some variables

2022-05-16T12:14:38Z

Make hmac_tfm static since it's not used anywhere else besides the file it is in. Remove declaration of hash_tfm since it doesn't exist. Signed-off-by: Stefan Berger Signed-off-by: Mimi Zohar

evm: Return INTEGRITY_PASS for enum integrity_status value '0'

2022-05-16T12:14:38Z

Return INTEGRITY_PASS for the enum integrity_status rather than 0. Signed-off-by: Stefan Berger Signed-off-by: Mimi Zohar

EVM: fix the evm= __setup handler return value

2022-02-22T23:11:33Z

__setup() handlers should return 1 if the parameter is handled. Returning 0 causes the entire string to be added to init's environment strings (limited to 32 strings), unnecessarily polluting it. Using the documented string "evm=fix" causes an Unknown parameter message: Unknown kernel command line parameters "BOOT_IMAGE=/boot/bzImage-517rc5 evm=fix", will be passed to user space. and that string is added to init's environment string space: Run /sbin/init as init process with arguments: /sbin/init with environment: HOME=/ TERM=linux BOOT_IMAGE=/boot/bzImage-517rc5 evm=fix With this change, using "evm=fix" acts as expected and an invalid option ("evm=evm") causes a warning to be printed: evm: invalid "evm" mode but init's environment is not polluted with this string, as expected. Fixes: 7102ebcd65c1 ("evm: permit only valid security.evm xattrs to be updated") Signed-off-by: Randy Dunlap Reported-by: Igor Zhbanov Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Signed-off-by: Mimi Zohar

evm: mark evm_fixmode as __ro_after_init

2021-10-28T22:52:49Z

The evm_fixmode is only configurable by command-line option and it is never modified outside initcalls, so declaring it with __ro_after_init is better. Signed-off-by: Austin Kim Cc: stable@vger.kernel.org Signed-off-by: Mimi Zohar

evm: Check xattr size discrepancy between kernel and user

2021-06-21T12:34:21Z

The kernel and the user obtain an xattr value in two different ways: kernel (EVM): uses vfs_getxattr_alloc() which obtains the xattr value from the filesystem handler (raw value); user (ima-evm-utils): uses vfs_getxattr() which obtains the xattr value from the LSMs (normalized value). Normally, this does not have an impact unless security.selinux is set with setfattr, with a value not terminated by '\0' (this is not the recommended way, security.selinux should be set with the appropriate tools such as chcon and restorecon). In this case, the kernel and the user see two different xattr values: the former sees the xattr value without '\0' (raw value), the latter sees the value with '\0' (value normalized by SELinux). This could result in two different verification outcomes from EVM and ima-evm-utils, if a signature was calculated with a security.selinux value terminated by '\0' and the value set in the filesystem is not terminated by '\0'. The former would report verification failure due to the missing '\0', while the latter would report verification success (because it gets the normalized value with '\0'). This patch mitigates this issue by comparing in evm_calc_hmac_or_hash() the size of the xattr returned by the two xattr functions and by warning the user if there is a discrepancy. Signed-off-by: Roberto Sassu Suggested-by: Mimi Zohar Signed-off-by: Mimi Zohar

evm: output EVM digest calculation info

2021-06-20T15:10:25Z

Output the data used in calculating the EVM digest and the resulting digest as ascii hexadecimal strings. Suggested-by: Lakshmi Ramasubramanian (CONFIG_DYNAMIC_DEBUG) Reviewed-by: Lakshmi Ramasubramanian Reported-by: kernel test robot (Use %zu for size_t) Signed-off-by: Mimi Zohar

ima/evm: Fix type mismatch

2021-06-08T20:29:10Z

The endianness of a variable written to the measurement list cannot be determined at compile time, as it depends on the value of the ima_canonical_fmt global variable (set through a kernel option with the same name if the machine is big endian). If ima_canonical_fmt is false, the endianness of a variable is the same as the machine; if ima_canonical_fmt is true, the endianness is little endian. The warning arises due to this type of instruction: var = cpu_to_leXX(var) which tries to assign a value in little endian to a variable with native endianness (little or big endian). Given that the variables set with this instruction are not used in any operation but just written to a buffer, it is safe to force the type of the value being set to be the same of the type of the variable with: var = (__force )cpu_to_leXX(var) Reported-by: kernel test robot Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar

evm: Don't return an error in evm_write_xattrs() if audit is not enabled

2021-06-03T14:03:40Z

This patch avoids that evm_write_xattrs() returns an error when audit is not enabled. The ab variable can be NULL and still be passed to the other audit_log_() functions, as those functions do not include any instruction. Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar

ima: Define new template fields xattrnames, xattrlengths and xattrvalues

2021-06-02T22:56:13Z

This patch defines the new template fields xattrnames, xattrlengths and xattrvalues, which contain respectively a list of xattr names (strings, separated by |), lengths (u32, hex) and values (hex). If an xattr is not present, the name and length are not displayed in the measurement list. Reported-by: kernel test robot (Missing prototype def) Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar

evm: Verify portable signatures against all protected xattrs

2021-06-01T19:17:31Z

Currently, the evm_config_default_xattrnames array contains xattr names only related to LSMs which are enabled in the kernel configuration. However, EVM portable signatures do not depend on local information and a vendor might include in the signature calculation xattrs that are not enabled in the target platform. Just including all xattrs names in evm_config_default_xattrnames is not a safe approach, because a target system might have already calculated signatures or HMACs based only on the enabled xattrs. After applying this patch, EVM would verify those signatures and HMACs with all xattrs instead. The non-enabled ones, which could possibly exist, would cause a verification error. Thus, this patch adds a new field named enabled to the xattr_list structure, which is set to true if the LSM associated to a given xattr name is enabled in the kernel configuration. The non-enabled xattrs are taken into account only in evm_calc_hmac_or_hash(), if the passed security.evm type is EVM_XATTR_PORTABLE_DIGSIG. The new function evm_protected_xattr_if_enabled() has been defined so that IMA can include all protected xattrs and not only the enabled ones in the measurement list, if the new template fields xattrnames, xattrlengths or xattrvalues have been included in the template format. Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar