Commit d632c047 authored by Ingo Franzki's avatar Ingo Franzki Committed by Martin Schwidefsky

s390/pkey: Add sysfs attributes to emit protected key blobs

Add binary read-only sysfs attributes for the pkey module
that can be used to read random protected keys from.
Keys are read from these attributes using a cat-like interface.

A typical use case for those keys is to encrypt a swap device
using the paes cipher. During processing of /etc/crypttab, the
random protected key to encrypt the swap device is read from
one of the attributes.

The following attributes are added:
  protkey/aes_128
  protkey/aes_192
  protkey/aes_256
  protkey/aes_128_xts
  protkey/aes_256_xts
Each attribute emits a protected key blob for the corresponding
key size and cipher mode.
Signed-off-by: default avatarIngo Franzki <ifranzki@linux.ibm.com>
Reviewed-by: default avatarHarald Freudenberger <freude@linux.ibm.com>
Reviewed-by: default avatarHendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 0534bde7
...@@ -1254,6 +1254,132 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd, ...@@ -1254,6 +1254,132 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
/* /*
* Sysfs and file io operations * Sysfs and file io operations
*/ */
/*
* Sysfs attribute read function for all protected key binary attributes.
* The implementation can not deal with partial reads, because a new random
* protected key blob is generated with each read. In case of partial reads
* (i.e. off != 0 or count < key blob size) -EINVAL is returned.
*/
static ssize_t pkey_protkey_aes_attr_read(u32 keytype, bool is_xts, char *buf,
loff_t off, size_t count)
{
struct protaeskeytoken protkeytoken;
struct pkey_protkey protkey;
int rc;
if (off != 0 || count < sizeof(protkeytoken))
return -EINVAL;
if (is_xts)
if (count < 2 * sizeof(protkeytoken))
return -EINVAL;
memset(&protkeytoken, 0, sizeof(protkeytoken));
protkeytoken.type = TOKTYPE_NON_CCA;
protkeytoken.version = TOKVER_PROTECTED_KEY;
protkeytoken.keytype = keytype;
rc = pkey_genprotkey(protkeytoken.keytype, &protkey);
if (rc)
return rc;
protkeytoken.len = protkey.len;
memcpy(&protkeytoken.protkey, &protkey.protkey, protkey.len);
memcpy(buf, &protkeytoken, sizeof(protkeytoken));
if (is_xts) {
rc = pkey_genprotkey(protkeytoken.keytype, &protkey);
if (rc)
return rc;
protkeytoken.len = protkey.len;
memcpy(&protkeytoken.protkey, &protkey.protkey, protkey.len);
memcpy(buf + sizeof(protkeytoken), &protkeytoken,
sizeof(protkeytoken));
return 2 * sizeof(protkeytoken);
}
return sizeof(protkeytoken);
}
static ssize_t protkey_aes_128_read(struct file *filp,
struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t off,
size_t count)
{
return pkey_protkey_aes_attr_read(PKEY_KEYTYPE_AES_128, false, buf,
off, count);
}
static ssize_t protkey_aes_192_read(struct file *filp,
struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t off,
size_t count)
{
return pkey_protkey_aes_attr_read(PKEY_KEYTYPE_AES_192, false, buf,
off, count);
}
static ssize_t protkey_aes_256_read(struct file *filp,
struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t off,
size_t count)
{
return pkey_protkey_aes_attr_read(PKEY_KEYTYPE_AES_256, false, buf,
off, count);
}
static ssize_t protkey_aes_128_xts_read(struct file *filp,
struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t off,
size_t count)
{
return pkey_protkey_aes_attr_read(PKEY_KEYTYPE_AES_128, true, buf,
off, count);
}
static ssize_t protkey_aes_256_xts_read(struct file *filp,
struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t off,
size_t count)
{
return pkey_protkey_aes_attr_read(PKEY_KEYTYPE_AES_256, true, buf,
off, count);
}
static BIN_ATTR_RO(protkey_aes_128, sizeof(struct protaeskeytoken));
static BIN_ATTR_RO(protkey_aes_192, sizeof(struct protaeskeytoken));
static BIN_ATTR_RO(protkey_aes_256, sizeof(struct protaeskeytoken));
static BIN_ATTR_RO(protkey_aes_128_xts, 2 * sizeof(struct protaeskeytoken));
static BIN_ATTR_RO(protkey_aes_256_xts, 2 * sizeof(struct protaeskeytoken));
static struct bin_attribute *protkey_attrs[] = {
&bin_attr_protkey_aes_128,
&bin_attr_protkey_aes_192,
&bin_attr_protkey_aes_256,
&bin_attr_protkey_aes_128_xts,
&bin_attr_protkey_aes_256_xts,
NULL
};
static struct attribute_group protkey_attr_group = {
.name = "protkey",
.bin_attrs = protkey_attrs,
};
static const struct attribute_group *pkey_attr_groups[] = {
&protkey_attr_group,
NULL,
};
static const struct file_operations pkey_fops = { static const struct file_operations pkey_fops = {
.owner = THIS_MODULE, .owner = THIS_MODULE,
.open = nonseekable_open, .open = nonseekable_open,
...@@ -1266,6 +1392,7 @@ static struct miscdevice pkey_dev = { ...@@ -1266,6 +1392,7 @@ static struct miscdevice pkey_dev = {
.minor = MISC_DYNAMIC_MINOR, .minor = MISC_DYNAMIC_MINOR,
.mode = 0666, .mode = 0666,
.fops = &pkey_fops, .fops = &pkey_fops,
.groups = pkey_attr_groups,
}; };
/* /*
......
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