linux-stable.git/security/integrity/evm, branch linux-5.10.y

evm: Complete description of evm_inode_setattr()

2023-07-27T06:43:35+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"

2022-07-21T19:20:02+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

2022-04-08T12:40:00+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

2021-11-18T13:03:46+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: fix writing /evm overflow

2021-07-14T14:56:04+00:00

[ Upstream commit 49219d9b8785ba712575c40e48ce0f7461254626 ]

EVM_SETUP_COMPLETE is defined as 0x80000000, which is larger than INT_MAX.
The "-fno-strict-overflow" compiler option properly prevents signaling
EVM that the EVM policy setup is complete.  Define and read an unsigned
int.

Fixes: f00d79750712 ("EVM: Allow userspace to signal an RSA key has been loaded")
Signed-off-by: Mimi Zohar 
Signed-off-by: Sasha Levin

evm: Refuse EVM_ALLOW_METADATA_WRITES only if an HMAC key is loaded

2021-07-14T14:55:46+00:00

commit 9acc89d31f0c94c8e573ed61f3e4340bbd526d0c upstream.

EVM_ALLOW_METADATA_WRITES is an EVM initialization flag that can be set to
temporarily disable metadata verification until all xattrs/attrs necessary
to verify an EVM portable signature are copied to the file. This flag is
cleared when EVM is initialized with an HMAC key, to avoid that the HMAC is
calculated on unverified xattrs/attrs.

Currently EVM unnecessarily denies setting this flag if EVM is initialized
with a public key, which is not a concern as it cannot be used to trust
xattrs/attrs updates. This patch removes this limitation.

Fixes: ae1ba1676b88e ("EVM: Allow userland to permit modification of EVM-protected metadata")
Signed-off-by: Roberto Sassu 
Cc: stable@vger.kernel.org # 4.16.x
Signed-off-by: Mimi Zohar 
Signed-off-by: Greg Kroah-Hartman

evm: Execute evm_inode_init_security() only when an HMAC key is loaded

2021-07-14T14:55:46+00:00

commit 9eea2904292c2d8fa98df141d3bf7c41ec9dc1b5 upstream.

evm_inode_init_security() requires an HMAC key to calculate the HMAC on
initial xattrs provided by LSMs. However, it checks generically whether a
key has been loaded, including also public keys, which is not correct as
public keys are not suitable to calculate the HMAC.

Originally, support for signature verification was introduced to verify a
possibly immutable initial ram disk, when no new files are created, and to
switch to HMAC for the root filesystem. By that time, an HMAC key should
have been loaded and usable to calculate HMACs for new files.

More recently support for requiring an HMAC key was removed from the
kernel, so that signature verification can be used alone. Since this is a
legitimate use case, evm_inode_init_security() should not return an error
when no HMAC key has been loaded.

This patch fixes this problem by replacing the evm_key_loaded() check with
a check of the EVM_INIT_HMAC flag in evm_initialized.

Fixes: 26ddabfe96b ("evm: enable EVM when X509 certificate is loaded")
Signed-off-by: Roberto Sassu 
Cc: stable@vger.kernel.org # 4.5.x
Signed-off-by: Mimi Zohar 
Signed-off-by: Greg Kroah-Hartman

evm: Fix memleak in init_desc

2021-03-04T10:37:40+00:00

[ Upstream commit ccf11dbaa07b328fa469415c362d33459c140a37 ]

tmp_tfm is allocated, but not freed on subsequent kmalloc failure, which
leads to a memory leak.  Free tmp_tfm.

Fixes: d46eb3699502b ("evm: crypto hash replaced by shash")
Signed-off-by: Dinghao Liu 
[zohar@linux.ibm.com: formatted/reworded patch description]
Signed-off-by: Mimi Zohar 
Signed-off-by: Sasha Levin

evm: Check size of security.evm before using it

2020-09-15T17:47:42+00:00

This patch checks the size for the EVM_IMA_XATTR_DIGSIG and
EVM_XATTR_PORTABLE_DIGSIG types to ensure that the algorithm is read from
the buffer returned by vfs_getxattr_alloc().

Cc: stable@vger.kernel.org # 4.19.x
Fixes: 5feeb61183dde ("evm: Allow non-SHA1 digital signatures")
Signed-off-by: Roberto Sassu 
Signed-off-by: Mimi Zohar

integrity: invalid kernel parameters feedback

2020-09-09T02:03:50+00:00

Don't silently ignore unknown or invalid ima_{policy,appraise,hash} and evm
kernel boot command line options.

Signed-off-by: Bruno Meneguele 
Signed-off-by: Mimi Zohar