std::string RetrieveSecurityContext(key_serial_t key) {
// Simply assume this size is enough in practice.
const int kMaxSupportedSize = 256;
std::string context;
context.resize(kMaxSupportedSize);
long retval = keyctl_get_security(key, context.data(), kMaxSupportedSize);
if (retval < 0) {
error(1, errno, "Cannot get security context of key %x", key);
return std::string();
}
if (retval > kMaxSupportedSize) {
error(1, 0, "The key has unexpectedly long security context than %d", kMaxSupportedSize);
return std::string();
}
context.resize(retval);
return context;
}
/*
* the key control system call, 32-bit compatibility version for 64-bit archs
* - this should only be called if the 64-bit arch uses weird pointers in
* 32-bit mode or doesn't guarantee that the top 32-bits of the argument
* registers on taking a 32-bit syscall are zero
* - if you can, you should call sys_keyctl directly
*/
asmlinkage long compat_sys_keyctl(u32 option,
u32 arg2, u32 arg3, u32 arg4, u32 arg5)
{
switch (option) {
case KEYCTL_GET_KEYRING_ID:
return keyctl_get_keyring_ID(arg2, arg3);
case KEYCTL_JOIN_SESSION_KEYRING:
return keyctl_join_session_keyring(compat_ptr(arg2));
case KEYCTL_UPDATE:
return keyctl_update_key(arg2, compat_ptr(arg3), arg4);
case KEYCTL_REVOKE:
return keyctl_revoke_key(arg2);
case KEYCTL_DESCRIBE:
return keyctl_describe_key(arg2, compat_ptr(arg3), arg4);
case KEYCTL_CLEAR:
return keyctl_keyring_clear(arg2);
case KEYCTL_LINK:
return keyctl_keyring_link(arg2, arg3);
case KEYCTL_UNLINK:
return keyctl_keyring_unlink(arg2, arg3);
case KEYCTL_SEARCH:
return keyctl_keyring_search(arg2, compat_ptr(arg3),
compat_ptr(arg4), arg5);
case KEYCTL_READ:
return keyctl_read_key(arg2, compat_ptr(arg3), arg4);
case KEYCTL_CHOWN:
return keyctl_chown_key(arg2, arg3, arg4);
case KEYCTL_SETPERM:
return keyctl_setperm_key(arg2, arg3);
case KEYCTL_INSTANTIATE:
return keyctl_instantiate_key(arg2, compat_ptr(arg3), arg4,
arg5);
case KEYCTL_NEGATE:
return keyctl_negate_key(arg2, arg3, arg4);
case KEYCTL_SET_REQKEY_KEYRING:
return keyctl_set_reqkey_keyring(arg2);
case KEYCTL_SET_TIMEOUT:
return keyctl_set_timeout(arg2, arg3);
case KEYCTL_ASSUME_AUTHORITY:
return keyctl_assume_authority(arg2);
case KEYCTL_GET_SECURITY:
return keyctl_get_security(arg2, compat_ptr(arg3), arg4);
case KEYCTL_SESSION_TO_PARENT:
return keyctl_session_to_parent();
default:
return -EOPNOTSUPP;
}
} /* end compat_sys_keyctl() */
