kernel/linux.git/security, branch v5.18.16

lockdown: Fix kexec lockdown bypass with ima policy

2022-07-29T15:27:55+00:00

commit 543ce63b664e2c2f9533d089a4664b559c3e6b5b upstream. 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 Signed-off-by: Greg Kroah-Hartman

x86/retbleed: Add fine grained Kconfig knobs

2022-07-23T10:56:56+00:00

commit f43b9876e857c739d407bc56df288b0ebe1a9164 upstream. 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 [cascardo: there is no CONFIG_OBJTOOL] [cascardo: objtool calling and option parsing has changed] Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

ima: Fix potential memory leak in ima_init_crypto()

2022-07-22T08:21:41+00:00

[ Upstream commit 067d2521874135267e681c19d42761c601d503d6 ] 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 Signed-off-by: Sasha Levin

ima: force signature verification when CONFIG_KEXEC_SIG is configured

2022-07-22T08:21:40+00:00

[ Upstream commit af16df54b89dee72df253abc5e7b5e8a6d16c11c ] 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 Signed-off-by: Sasha Levin

ima: Fix a potential integer overflow in ima_appraise_measurement

2022-07-22T08:21:26+00:00

[ Upstream commit d2ee2cfc4aa85ff6a2a3b198a3a524ec54e3d999 ] 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 Signed-off-by: Sasha Levin

Revert "evm: Fix memleak in init_desc"

2022-07-22T08:21:22+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

selinux: free contexts previously transferred in selinux_add_opt()

2022-06-22T12:28:10+00:00

commit cad140d00899e7a9cb6fe93b282051df589e671c upstream. `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 Signed-off-by: Greg Kroah-Hartman

KEYS: trusted: tpm2: Fix migratable logic

2022-06-14T16:45:17+00:00

commit dda5384313a40ecbaafd8a9a80f47483255e4c4d upstream. 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 Signed-off-by: Greg Kroah-Hartman

ima: remove the IMA_TEMPLATE Kconfig option

2022-06-09T08:30:49+00:00

commit 891163adf180bc369b2f11c9dfce6d2758d2a5bd upstream. The original 'ima' measurement list template contains a hash, defined as 20 bytes, and a null terminated pathname, limited to 255 characters. Other measurement list templates permit both larger hashes and longer pathnames. When the "ima" template is configured as the default, a new measurement list template (ima_template=) must be specified before specifying a larger hash algorithm (ima_hash=) on the boot command line. To avoid this boot command line ordering issue, remove the legacy "ima" template configuration option, allowing it to still be specified on the boot command line. The root cause of this issue is that during the processing of ima_hash, we would try to check whether the hash algorithm is compatible with the template. If the template is not set at the moment we do the check, we check the algorithm against the configured default template. If the default template is "ima", then we reject any hash algorithm other than sha1 and md5. For example, if the compiled default template is "ima", and the default algorithm is sha1 (which is the current default). In the cmdline, we put in "ima_hash=sha256 ima_template=ima-ng". The expected behavior would be that ima starts with ima-ng as the template and sha256 as the hash algorithm. However, during the processing of "ima_hash=", "ima_template=" has not been processed yet, and hash_setup would check the configured hash algorithm against the compiled default: ima, and reject sha256. So at the end, the hash algorithm that is actually used will be sha1. With template "ima" removed from the configured default, we ensure that the default tempalte would at least be "ima-ng" which allows for basically any hash algorithm. This change would not break the algorithm compatibility checks for IMA. Fixes: 4286587dccd43 ("ima: add Kconfig default measurement list template") Signed-off-by: GUO Zihua Cc: Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman

landlock: Fix same-layer rule unions

2022-06-09T08:30:48+00:00

commit 8ba0005ff418ec356e176b26eaa04a6ac755d05b upstream. The original behavior was to check if the full set of requested accesses was allowed by at least a rule of every relevant layer. This didn't take into account requests for multiple accesses and same-layer rules allowing the union of these accesses in a complementary way. As a result, multiple accesses requested on a file hierarchy matching rules that, together, allowed these accesses, but without a unique rule allowing all of them, was illegitimately denied. This case should be rare in practice and it can only be triggered by the path_rename or file_open hook implementations. For instance, if, for the same layer, a rule allows execution beneath /a/b and another rule allows read beneath /a, requesting access to read and execute at the same time for /a/b should be allowed for this layer. This was an inconsistency because the union of same-layer rule accesses was already allowed if requested once at a time anyway. This fix changes the way allowed accesses are gathered over a path walk. To take into account all these rule accesses, we store in a matrix all layer granting the set of requested accesses, according to the handled accesses. To avoid heap allocation, we use an array on the stack which is 2*13 bytes. A following commit bringing the LANDLOCK_ACCESS_FS_REFER access right will increase this size to reach 112 bytes (2*14*4) in case of link or rename actions. Add a new layout1.layer_rule_unions test to check that accesses from different rules pertaining to the same layer are ORed in a file hierarchy. Also test that it is not the case for rules from different layers. Reviewed-by: Paul Moore Link: https://lore.kernel.org/r/20220506161102.525323-5-mic@digikod.net Cc: stable@vger.kernel.org Signed-off-by: Mickaël Salaün Signed-off-by: Greg Kroah-Hartman