diff options
Diffstat (limited to 'security/integrity/evm')
| -rw-r--r-- | security/integrity/evm/evm_crypto.c | 12 | ||||
| -rw-r--r-- | security/integrity/evm/evm_main.c | 4 |
2 files changed, 14 insertions, 2 deletions
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c index bf663915412e..d7f282d75cc1 100644 --- a/security/integrity/evm/evm_crypto.c +++ b/security/integrity/evm/evm_crypto.c @@ -151,8 +151,16 @@ static void hmac_add_misc(struct shash_desc *desc, struct inode *inode, memset(&hmac_misc, 0, sizeof(hmac_misc)); hmac_misc.ino = inode->i_ino; hmac_misc.generation = inode->i_generation; - hmac_misc.uid = from_kuid(inode->i_sb->s_user_ns, inode->i_uid); - hmac_misc.gid = from_kgid(inode->i_sb->s_user_ns, inode->i_gid); + /* The hmac uid and gid must be encoded in the initial user + * namespace (not the filesystems user namespace) as encoding + * them in the filesystems user namespace allows an attack + * where first they are written in an unprivileged fuse mount + * of a filesystem and then the system is tricked to mount the + * filesystem for real on next boot and trust it because + * everything is signed. + */ + hmac_misc.uid = from_kuid(&init_user_ns, inode->i_uid); + hmac_misc.gid = from_kgid(&init_user_ns, inode->i_gid); hmac_misc.mode = inode->i_mode; crypto_shash_update(desc, (const u8 *)&hmac_misc, sizeof(hmac_misc)); if (evm_hmac_attrs & EVM_ATTR_FSUUID) diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index ba8615576d4d..e2ed498c0f5f 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -145,6 +145,10 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, /* check value type */ switch (xattr_data->type) { case EVM_XATTR_HMAC: + if (xattr_len != sizeof(struct evm_ima_xattr_data)) { + evm_status = INTEGRITY_FAIL; + goto out; + } rc = evm_calc_hmac(dentry, xattr_name, xattr_value, xattr_value_len, calc.digest); if (rc) |