diff options
Diffstat (limited to 'security/integrity/evm/evm_secfs.c')
| -rw-r--r-- | security/integrity/evm/evm_secfs.c | 44 |
1 files changed, 31 insertions, 13 deletions
diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c index c11c1f7b3ddd..8a9db7dfca7e 100644 --- a/security/integrity/evm/evm_secfs.c +++ b/security/integrity/evm/evm_secfs.c @@ -10,8 +10,6 @@ * - Get the key and enable EVM */ -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt - #include <linux/audit.h> #include <linux/uaccess.h> #include <linux/init.h> @@ -68,12 +66,13 @@ static ssize_t evm_read_key(struct file *filp, char __user *buf, static ssize_t evm_write_key(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { - int i, ret; + unsigned int i; + int ret; if (!capable(CAP_SYS_ADMIN) || (evm_initialized & EVM_SETUP_COMPLETE)) return -EPERM; - ret = kstrtoint_from_user(buf, count, 0, &i); + ret = kstrtouint_from_user(buf, count, 0, &i); if (ret) return ret; @@ -82,12 +81,12 @@ static ssize_t evm_write_key(struct file *file, const char __user *buf, if (!i || (i & ~EVM_INIT_MASK) != 0) return -EINVAL; - /* Don't allow a request to freshly enable metadata writes if - * keys are loaded. + /* + * Don't allow a request to enable metadata writes if + * an HMAC key is loaded. */ if ((i & EVM_ALLOW_METADATA_WRITES) && - ((evm_initialized & EVM_KEY_MASK) != 0) && - !(evm_initialized & EVM_ALLOW_METADATA_WRITES)) + (evm_initialized & EVM_INIT_HMAC) != 0) return -EPERM; if (i & EVM_INIT_HMAC) { @@ -140,8 +139,12 @@ static ssize_t evm_read_xattrs(struct file *filp, char __user *buf, if (rc) return -ERESTARTSYS; - list_for_each_entry(xattr, &evm_config_xattrnames, list) + list_for_each_entry(xattr, &evm_config_xattrnames, list) { + if (!xattr->enabled) + continue; + size += strlen(xattr->name) + 1; + } temp = kmalloc(size + 1, GFP_KERNEL); if (!temp) { @@ -150,6 +153,9 @@ static ssize_t evm_read_xattrs(struct file *filp, char __user *buf, } list_for_each_entry(xattr, &evm_config_xattrnames, list) { + if (!xattr->enabled) + continue; + sprintf(temp + offset, "%s\n", xattr->name); offset += strlen(xattr->name) + 1; } @@ -191,7 +197,7 @@ static ssize_t evm_write_xattrs(struct file *file, const char __user *buf, ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_INTEGRITY_EVM_XATTR); - if (!ab) + if (!ab && IS_ENABLED(CONFIG_AUDIT)) return -ENOMEM; xattr = kmalloc(sizeof(struct xattr_list), GFP_KERNEL); @@ -200,6 +206,7 @@ static ssize_t evm_write_xattrs(struct file *file, const char __user *buf, goto out; } + xattr->enabled = true; xattr->name = memdup_user_nul(buf, count); if (IS_ERR(xattr->name)) { err = PTR_ERR(xattr->name); @@ -221,7 +228,7 @@ static ssize_t evm_write_xattrs(struct file *file, const char __user *buf, newattrs.ia_valid = ATTR_MODE; inode = evm_xattrs->d_inode; inode_lock(inode); - err = simple_setattr(evm_xattrs, &newattrs); + err = simple_setattr(&init_user_ns, evm_xattrs, &newattrs); inode_unlock(inode); if (!err) err = count; @@ -234,11 +241,22 @@ static ssize_t evm_write_xattrs(struct file *file, const char __user *buf, goto out; } - /* Guard against races in evm_read_xattrs */ + /* + * xattr_list_mutex guards against races in evm_read_xattrs(). + * Entries are only added to the evm_config_xattrnames list + * and never deleted. Therefore, the list is traversed + * using list_for_each_entry_lockless() without holding + * the mutex in evm_calc_hmac_or_hash(), evm_find_protected_xattrs() + * and evm_protected_xattr(). + */ mutex_lock(&xattr_list_mutex); list_for_each_entry(tmp, &evm_config_xattrnames, list) { if (strcmp(xattr->name, tmp->name) == 0) { err = -EEXIST; + if (!tmp->enabled) { + tmp->enabled = true; + err = count; + } mutex_unlock(&xattr_list_mutex); goto out; } @@ -250,7 +268,7 @@ static ssize_t evm_write_xattrs(struct file *file, const char __user *buf, audit_log_end(ab); return count; out: - audit_log_format(ab, " res=%d", err); + audit_log_format(ab, " res=%d", (err < 0) ? err : 0); audit_log_end(ab); if (xattr) { kfree(xattr->name); |