linux-toradex.git/security, branch v5.19-rc8

lockdown: Fix kexec lockdown bypass with ima policy

2022-07-20T16:56:48+00:00

The lockdown LSM is primarily used in conjunction with UEFI Secure Boot.
This LSM may also be used on machines without UEFI.  It can also be
enabled when UEFI Secure Boot is disabled.  One of lockdown's features
is to prevent kexec from loading untrusted kernels.  Lockdown can be
enabled through a bootparam or after the kernel has booted through
securityfs.

If IMA appraisal is used with the "ima_appraise=log" boot param,
lockdown can be defeated with kexec on any machine when Secure Boot is
disabled or unavailable.  IMA prevents setting "ima_appraise=log" from
the boot param when Secure Boot is enabled, but this does not cover
cases where lockdown is used without Secure Boot.

To defeat lockdown, boot without Secure Boot and add ima_appraise=log to
the kernel command line; then:

  $ echo "integrity" > /sys/kernel/security/lockdown
  $ echo "appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig" > \
    /sys/kernel/security/ima/policy
  $ kexec -ls unsigned-kernel

Add a call to verify ima appraisal is set to "enforce" whenever lockdown
is enabled.  This fixes CVE-2022-21505.

Cc: stable@vger.kernel.org
Fixes: 29d3c1c8dfe7 ("kexec: Allow kexec_file() with appropriate IMA policy when locked down")
Signed-off-by: Eric Snowberg 
Acked-by: Mimi Zohar 
Reviewed-by: John Haxby 
Signed-off-by: Linus Torvalds

Merge tag 'integrity-v5.19-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

2022-07-14T19:15:42+00:00

Pull integrity fixes from Mimi Zohar:
 "Here are a number of fixes for recently found bugs.

  Only 'ima: fix violation measurement list record' was introduced in
  the current release. The rest address existing bugs"

* tag 'integrity-v5.19-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: Fix potential memory leak in ima_init_crypto()
  ima: force signature verification when CONFIG_KEXEC_SIG is configured
  ima: Fix a potential integer overflow in ima_appraise_measurement
  ima: fix violation measurement list record
  Revert "evm: Fix memleak in init_desc"

ima: Fix potential memory leak in ima_init_crypto()

2022-07-13T14:13:58+00:00

On failure to allocate the SHA1 tfm, IMA fails to initialize and exits
without freeing the ima_algo_array. Add the missing kfree() for
ima_algo_array to avoid the potential memory leak.

Signed-off-by: Jianglei Nie 
Fixes: 6d94809af6b0 ("ima: Allocate and initialize tfm for each PCR bank")
Signed-off-by: Mimi Zohar

ima: force signature verification when CONFIG_KEXEC_SIG is configured

2022-07-13T14:13:41+00:00

Currently, an unsigned kernel could be kexec'ed when IMA arch specific
policy is configured unless lockdown is enabled. Enforce kernel
signature verification check in the kexec_file_load syscall when IMA
arch specific policy is configured.

Fixes: 99d5cadfde2b ("kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE")
Reported-and-suggested-by: Mimi Zohar 
Signed-off-by: Coiby Xu 
Signed-off-by: Mimi Zohar

ima: Fix a potential integer overflow in ima_appraise_measurement

2022-07-07T15:50:25+00:00

When the ima-modsig is enabled, the rc passed to evm_verifyxattr() may be
negative, which may cause the integer overflow problem.

Fixes: 39b07096364a ("ima: Implement support for module-style appended signatures")
Signed-off-by: Huaxin Lu 
Signed-off-by: Mimi Zohar

ima: fix violation measurement list record

2022-07-07T02:31:52+00:00

Although the violation digest in the IMA measurement list is always
zeroes, the size of the digest should be based on the hash algorithm.
Until recently the hash algorithm was hard coded to sha1.  Fix the
violation digest size included in the IMA measurement list.

This is just a cosmetic change which should not affect attestation.

Reported-by: Stefan Berger 
Fixes: 09091c44cb73 ("ima: use IMA default hash algorithm for integrity violations")
Tested-by: Stefan Berger 
Signed-off-by: Mimi Zohar

x86/retbleed: Add fine grained Kconfig knobs

2022-06-29T15:43:41+00:00

Do fine-grained Kconfig for all the various retbleed parts.

NOTE: if your compiler doesn't support return thunks this will
silently 'upgrade' your mitigation to IBPB, you might not like this.

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Borislav Petkov

selinux: free contexts previously transferred in selinux_add_opt()

2022-06-16T01:20:45+00:00

`selinux_add_opt()` stopped taking ownership of the passed context since
commit 70f4169ab421 ("selinux: parse contexts for mount options early").

    unreferenced object 0xffff888114dfd140 (size 64):
      comm "mount", pid 15182, jiffies 4295687028 (age 796.340s)
      hex dump (first 32 bytes):
        73 79 73 74 65 6d 5f 75 3a 6f 62 6a 65 63 74 5f  system_u:object_
        72 3a 74 65 73 74 5f 66 69 6c 65 73 79 73 74 65  r:test_filesyste
      backtrace:
        [] kmemdup_nul+0x24/0x80
        [] selinux_sb_eat_lsm_opts+0x293/0x560
        [] security_sb_eat_lsm_opts+0x58/0x80
        [] generic_parse_monolithic+0x82/0x180
        [] do_new_mount+0x1f5/0x550
        [] path_mount+0x2ab/0x1570
        [] __x64_sys_mount+0x20e/0x280
        [] do_syscall_64+0x34/0x80
        [] entry_SYSCALL_64_after_hwframe+0x46/0xb0

    unreferenced object 0xffff888108e71640 (size 64):
      comm "fsmount", pid 7607, jiffies 4295044974 (age 1601.016s)
      hex dump (first 32 bytes):
        73 79 73 74 65 6d 5f 75 3a 6f 62 6a 65 63 74 5f  system_u:object_
        72 3a 74 65 73 74 5f 66 69 6c 65 73 79 73 74 65  r:test_filesyste
      backtrace:
        [] memdup_user+0x21/0x90
        [] strndup_user+0x47/0xa0
        [] __do_sys_fsconfig+0x485/0x9f0
        [] do_syscall_64+0x34/0x80
        [] entry_SYSCALL_64_after_hwframe+0x46/0xb0

Cc: stable@vger.kernel.org
Fixes: 70f4169ab421 ("selinux: parse contexts for mount options early")
Signed-off-by: Christian Göttsche 
Signed-off-by: Paul Moore

Revert "evm: Fix memleak in init_desc"

2022-06-15T18:03:47+00:00

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

KEYS: trusted: tpm2: Fix migratable logic

2022-06-08T11:12:13+00:00

When creating (sealing) a new trusted key, migratable
trusted keys have the FIXED_TPM and FIXED_PARENT attributes
set, and non-migratable keys don't. This is backwards, and
also causes creation to fail when creating a migratable key
under a migratable parent. (The TPM thinks you are trying to
seal a non-migratable blob under a migratable parent.)

The following simple patch fixes the logic, and has been
tested for all four combinations of migratable and non-migratable
trusted keys and parent storage keys. With this logic, you will
get a proper failure if you try to create a non-migratable
trusted key under a migratable parent storage key, and all other
combinations work correctly.

Cc: stable@vger.kernel.org # v5.13+
Fixes: e5fb5d2c5a03 ("security: keys: trusted: Make sealed key properly interoperable")
Signed-off-by: David Safford 
Reviewed-by: Ahmad Fatoum 
Reviewed-by: Jarkko Sakkinen 
Signed-off-by: Jarkko Sakkinen