linux-stable.git/security/integrity/evm, branch linux-5.15.y

evm: Fix build warnings

2023-07-23T11:46:48+00:00

[ Upstream commit 996e0a97ebd7b11cb785794e2a83c20c1add9d92 ]

Fix build warnings (function parameters description) for
evm_read_protected_xattrs(), evm_set_key() and evm_verifyxattr().

Fixes: 7626676320f3 ("evm: provide a function to set the EVM key from the kernel") # v4.5+
Fixes: 8314b6732ae4 ("ima: Define new template fields xattrnames, xattrlengths and xattrvalues") # v5.14+
Fixes: 2960e6cb5f7c ("evm: additional parameter to pass integrity cache entry 'iint'") # v3.2+
Signed-off-by: Roberto Sassu 
Signed-off-by: Mimi Zohar 
Signed-off-by: Sasha Levin

evm: Complete description of evm_inode_setattr()

2023-07-23T11:46:48+00:00

[ Upstream commit b1de86d4248b273cb12c4cd7d20c08d459519f7d ]

Add the description for missing parameters of evm_inode_setattr() to
avoid the warning arising with W=n compile option.

Fixes: 817b54aa45db ("evm: add evm_inode_setattr to prevent updating an invalid security.evm") # v3.2+
Fixes: c1632a0f1120 ("fs: port ->setattr() to pass mnt_idmap") # v6.3+
Signed-off-by: Roberto Sassu 
Reviewed-by: Stefan Berger 
Signed-off-by: Mimi Zohar 
Signed-off-by: Sasha Levin

Revert "evm: Fix memleak in init_desc"

2022-07-21T19:24:14+00:00

commit 51dd64bb99e4478fc5280171acd8e1b529eadaf7 upstream.

This reverts commit ccf11dbaa07b328fa469415c362d33459c140a37.

Commit ccf11dbaa07b ("evm: Fix memleak in init_desc") said there is
memleak in init_desc. That may be incorrect, as we can see, tmp_tfm is
saved in one of the two global variables hmac_tfm or evm_tfm[hash_algo],
then if init_desc is called next time, there is no need to alloc tfm
again, so in the error path of kmalloc desc or crypto_shash_init(desc),
It is not a problem without freeing tmp_tfm.

And also that commit did not reset the global variable to NULL after
freeing tmp_tfm and this makes *tfm a dangling pointer which may cause a
UAF issue.

Reported-by: Guozihua (Scott) 
Signed-off-by: Xiu Jianfeng 
Signed-off-by: Mimi Zohar 
Signed-off-by: Greg Kroah-Hartman

EVM: fix the evm= __setup handler return value

2022-04-08T12:23:06+00:00

[ Upstream commit f2544f5e6c691679d56bb38637d2f347075b36fa ]

__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 
Signed-off-by: Sasha Levin

evm: mark evm_fixmode as __ro_after_init

2021-11-18T18:15:58+00:00

commit 32ba540f3c2a7ef61ed5a577ce25069a3d714fc9 upstream.

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 
Signed-off-by: Greg Kroah-Hartman

evm: Check xattr size discrepancy between kernel and user

2021-06-21T12:34:21+00:00

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

2021-06-20T15:10:25+00:00

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

2021-06-08T20:29:10+00:00

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

2021-06-03T14:03:40+00:00

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

2021-06-02T22:56:13+00:00

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