diff options
| author | Stefan Berger <stefanb@linux.ibm.com> | 2026-03-25 17:33:49 -0400 |
|---|---|---|
| committer | Mimi Zohar <zohar@linux.ibm.com> | 2026-04-01 10:16:53 -0400 |
| commit | 82bbd447199ff1441031d2eaf9afe041550cf525 (patch) | |
| tree | 292e2762b88320af684b83886ce5df57546468d4 /security | |
| parent | bab8e90bca64a87dd058527ae1d02596d35dc601 (diff) | |
evm: Enforce signatures version 3 with new EVM policy 'bit 3'
Enable the configuration of EVM so that it requires that asymmetric
signatures it accepts are of version 3 (sigv3). To enable this, introduce
bit 3 (value 0x0008) that the user may write to EVM's securityfs policy
configuration file 'evm' for sigv3 enforcement.
Mention bit 3 in the documentation.
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Diffstat (limited to 'security')
| -rw-r--r-- | security/integrity/evm/evm.h | 3 | ||||
| -rw-r--r-- | security/integrity/evm/evm_main.c | 14 |
2 files changed, 16 insertions, 1 deletions
diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h index 51aba5a54275..694552aceaf8 100644 --- a/security/integrity/evm/evm.h +++ b/security/integrity/evm/evm.h @@ -20,11 +20,12 @@ #define EVM_INIT_HMAC 0x0001 #define EVM_INIT_X509 0x0002 #define EVM_ALLOW_METADATA_WRITES 0x0004 +#define EVM_SIGV3_REQUIRED 0x0008 #define EVM_SETUP_COMPLETE 0x80000000 /* userland has signaled key load */ #define EVM_KEY_MASK (EVM_INIT_HMAC | EVM_INIT_X509) #define EVM_INIT_MASK (EVM_INIT_HMAC | EVM_INIT_X509 | EVM_SETUP_COMPLETE | \ - EVM_ALLOW_METADATA_WRITES) + EVM_ALLOW_METADATA_WRITES | EVM_SIGV3_REQUIRED) struct xattr_list { struct list_head list; diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index b15d9d933b84..b59e3f121b8a 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -136,6 +136,14 @@ static bool evm_hmac_disabled(void) return true; } +static bool evm_sigv3_required(void) +{ + if (evm_initialized & EVM_SIGV3_REQUIRED) + return true; + + return false; +} + static int evm_find_protected_xattrs(struct dentry *dentry) { struct inode *inode = d_backing_inode(dentry); @@ -258,6 +266,12 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, } hdr = (struct signature_v2_hdr *)xattr_data; + + if (evm_sigv3_required() && hdr->version != 3) { + evm_status = INTEGRITY_FAIL; + goto out; + } + digest.hdr.algo = hdr->hash_algo; rc = evm_calc_hash(dentry, xattr_name, xattr_value, xattr_value_len, xattr_data->type, &digest, |