diff options
Diffstat (limited to 'security/integrity')
| -rw-r--r-- | security/integrity/evm/evm_main.c | 15 | ||||
| -rw-r--r-- | security/integrity/ima/ima_crypto.c | 32 | ||||
| -rw-r--r-- | security/integrity/ima/ima_policy.c | 1 |
3 files changed, 44 insertions, 4 deletions
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index cdbde1762189..b980a6ce5c79 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -275,12 +275,23 @@ static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name, * @xattr_value: pointer to the new extended attribute value * @xattr_value_len: pointer to the new extended attribute value length * - * Updating 'security.evm' requires CAP_SYS_ADMIN privileges and that - * the current value is valid. + * Before allowing the 'security.evm' protected xattr to be updated, + * verify the existing value is valid. As only the kernel should have + * access to the EVM encrypted key needed to calculate the HMAC, prevent + * userspace from writing HMAC value. Writing 'security.evm' requires + * requires CAP_SYS_ADMIN privileges. */ int evm_inode_setxattr(struct dentry *dentry, const char *xattr_name, const void *xattr_value, size_t xattr_value_len) { + const struct evm_ima_xattr_data *xattr_data = xattr_value; + + if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) { + if (!xattr_value_len) + return -EINVAL; + if (xattr_data->type != EVM_IMA_XATTR_DIGSIG) + return -EPERM; + } return evm_protect_xattr(dentry, xattr_name, xattr_value, xattr_value_len); } diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c index a02e0791cf15..9da974c0f958 100644 --- a/security/integrity/ima/ima_crypto.c +++ b/security/integrity/ima/ima_crypto.c @@ -24,6 +24,36 @@ static struct crypto_shash *ima_shash_tfm; +/** + * ima_kernel_read - read file content + * + * This is a function for reading file content instead of kernel_read(). + * It does not perform locking checks to ensure it cannot be blocked. + * It does not perform security checks because it is irrelevant for IMA. + * + */ +static int ima_kernel_read(struct file *file, loff_t offset, + char *addr, unsigned long count) +{ + mm_segment_t old_fs; + char __user *buf = addr; + ssize_t ret; + + if (!(file->f_mode & FMODE_READ)) + return -EBADF; + if (!file->f_op->read && !file->f_op->aio_read) + return -EINVAL; + + old_fs = get_fs(); + set_fs(get_ds()); + if (file->f_op->read) + ret = file->f_op->read(file, buf, count, &offset); + else + ret = do_sync_read(file, buf, count, &offset); + set_fs(old_fs); + return ret; +} + int ima_init_crypto(void) { long rc; @@ -70,7 +100,7 @@ int ima_calc_file_hash(struct file *file, char *digest) while (offset < i_size) { int rbuf_len; - rbuf_len = kernel_read(file, offset, rbuf, PAGE_SIZE); + rbuf_len = ima_kernel_read(file, offset, rbuf, PAGE_SIZE); if (rbuf_len < 0) { rc = rbuf_len; break; diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 399433ad614e..a9c3d3cd1990 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -73,7 +73,6 @@ static struct ima_rule_entry default_rules[] = { {.action = DONT_MEASURE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC}, {.action = DONT_MEASURE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC}, {.action = DONT_MEASURE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC}, - {.action = DONT_MEASURE,.fsmagic = RAMFS_MAGIC,.flags = IMA_FSMAGIC}, {.action = DONT_MEASURE,.fsmagic = DEVPTS_SUPER_MAGIC,.flags = IMA_FSMAGIC}, {.action = DONT_MEASURE,.fsmagic = BINFMTFS_MAGIC,.flags = IMA_FSMAGIC}, {.action = DONT_MEASURE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC}, |