src/shared/creds-util.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 #pragma once
   3
   4 #include <inttypes.h>
   5 #include <stdbool.h>
   6 #include <sys/types.h>
   7
   8 #include "sd-id128.h"
   9
  10 #include "fd-util.h"
  11 #include "time-util.h"
  12
  13 #define CREDENTIAL_NAME_MAX FDNAME_MAX
  14
  15 /* Put a size limit on the individual credential */
  16 #define CREDENTIAL_SIZE_MAX (1024U*1024U)
  17
  18 /* Refuse to store more than 1M per service, after all this is unswappable memory. Note that for now we put
  19  * this to the same limit as the per-credential limit, i.e. if the user has n > 1 credentials instead of 1 it
  20  * won't get them more space. */
  21 #define CREDENTIALS_TOTAL_SIZE_MAX CREDENTIAL_SIZE_MAX
  22
  23 /* Put a size limit on encrypted credentials (which is the same as the unencrypted size plus a spacious 128K of extra
  24  * space for headers, IVs, exported TPM2 key material and so on. */
  25 #define CREDENTIAL_ENCRYPTED_SIZE_MAX (CREDENTIAL_SIZE_MAX + 128U*1024U)
  26
  27 bool credential_name_valid(const char *s);
  28 bool credential_glob_valid(const char *s);
  29
  30 /* Where creds have been passed to the local execution context */
  31 int get_credentials_dir(const char **ret);
  32 int get_encrypted_credentials_dir(const char **ret);
  33
  34 int open_credentials_dir(void);
  35
  36 /* Where creds have been passed to the system */
  37 #define SYSTEM_CREDENTIALS_DIRECTORY "/run/credentials/@system"
  38 #define ENCRYPTED_SYSTEM_CREDENTIALS_DIRECTORY "/run/credentials/@encrypted"
  39
  40 int read_credential(const char *name, void **ret, size_t *ret_size); /* use in services! */
  41 int read_credential_with_decryption(const char *name, void **ret, size_t *ret_size); /* use in generators + pid1! */
  42
  43 int read_credential_strings_many_internal(const char *first_name, char **first_value, ...);
  44
  45 #define read_credential_strings_many(first_name, first_value, ...) \
  46         read_credential_strings_many_internal(first_name, first_value, __VA_ARGS__, NULL)
  47
  48 int read_credential_bool(const char *name);
  49
  50 typedef enum CredentialSecretFlags {
  51         CREDENTIAL_SECRET_GENERATE             = 1 << 0,
  52         CREDENTIAL_SECRET_WARN_NOT_ENCRYPTED   = 1 << 1,
  53         CREDENTIAL_SECRET_FAIL_ON_TEMPORARY_FS = 1 << 2,
  54 } CredentialSecretFlags;
  55
  56 int get_credential_host_secret(CredentialSecretFlags flags, struct iovec *ret);
  57
  58 int get_credential_user_password(const char *username, char **ret_password, bool *ret_is_hashed);
  59
  60 typedef enum CredentialFlags {
  61         CREDENTIAL_ALLOW_NULL = 1 << 0, /* allow decryption of NULL key, even if TPM is around */
  62         CREDENTIAL_ANY_SCOPE  = 1 << 1, /* allow decryption of both system and user credentials */
  63 } CredentialFlags;
  64
  65 /* The four modes we support: keyed only by on-disk key, only by TPM2 HMAC key, and by the combination of
  66  * both, as well as one with a fixed zero length key if TPM2 is missing (the latter of course provides no
  67  * authenticity or confidentiality, but is still useful for integrity protection, and makes things simpler
  68  * for us to handle). */
  69 #define CRED_AES256_GCM_BY_HOST               SD_ID128_MAKE(5a,1c,6a,86,df,9d,40,96,b1,d5,a6,5e,08,62,f1,9a)
  70 #define CRED_AES256_GCM_BY_HOST_SCOPED        SD_ID128_MAKE(55,b9,ed,1d,38,59,4d,43,a8,31,9d,2e,bb,33,2a,c6)
  71 #define CRED_AES256_GCM_BY_TPM2_HMAC          SD_ID128_MAKE(0c,7c,c0,7b,11,76,45,91,9c,4b,0b,ea,08,bc,20,fe)
  72 #define CRED_AES256_GCM_BY_TPM2_HMAC_WITH_PK  SD_ID128_MAKE(fa,f7,eb,93,41,e3,41,2c,a1,a4,36,f9,5a,29,36,2f)
  73 #define CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC SD_ID128_MAKE(93,a8,94,09,48,74,44,90,90,ca,f2,fc,93,ca,b5,53)
  74 #define CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_SCOPED            \
  75                                               SD_ID128_MAKE(ef,4a,c1,36,79,a9,48,0e,a7,db,68,89,7f,9f,16,5d)
  76 #define CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK           \
  77                                               SD_ID128_MAKE(af,49,50,a8,49,13,4e,b1,a7,38,46,30,4f,f3,0c,05)
  78 #define CRED_AES256_GCM_BY_HOST_AND_TPM2_HMAC_WITH_PK_SCOPED    \
  79                                               SD_ID128_MAKE(ad,bc,4c,a3,ef,b6,42,01,ba,88,1b,6f,2e,40,95,ea)
  80 #define CRED_AES256_GCM_BY_NULL               SD_ID128_MAKE(05,84,69,da,f6,f5,43,24,80,05,49,da,0f,8e,a2,fb)
  81
  82 /* Two special IDs to pick a general automatic mode (i.e. tpm2+host if TPM2 exists, only host otherwise) or
  83  * an initrd-specific automatic mode (i.e. tpm2 if firmware can do it, otherwise fixed zero-length key, and
  84  * never involve host keys). These IDs will never be stored on disk, but are useful only internally while
  85  * figuring out what precisely to write to disk. To mark that these aren't a "real" type, we'll prefix them
  86  * with an underscore. */
  87 #define _CRED_AUTO                            SD_ID128_MAKE(a2,19,cb,07,85,b2,4c,04,b1,6d,18,ca,b9,d2,ee,01)
  88 #define _CRED_AUTO_INITRD                     SD_ID128_MAKE(02,dc,8e,de,3a,02,43,ab,a9,ec,54,9c,05,e6,a0,71)
  89 #define _CRED_AUTO_SCOPED                     SD_ID128_MAKE(23,88,96,85,6f,74,48,8a,9c,78,6f,6a,b0,e7,3b,6a)
  90
  91 int encrypt_credential_and_warn(sd_id128_t with_key, const char *name, usec_t timestamp, usec_t not_after, const char *tpm2_device, uint32_t tpm2_hash_pcr_mask, const char *tpm2_pubkey_path, uint32_t tpm2_pubkey_pcr_mask, uid_t uid, const struct iovec *input, CredentialFlags flags, struct iovec *ret);
  92 int decrypt_credential_and_warn(const char *validate_name, usec_t validate_timestamp, const char *tpm2_device, const char *tpm2_signature_path, uid_t uid, const struct iovec *input, CredentialFlags flags, struct iovec *ret);
  93
  94 int ipc_encrypt_credential(const char *name, usec_t timestamp, usec_t not_after, uid_t uid, const struct iovec *input, CredentialFlags flags, struct iovec *ret);
  95 int ipc_decrypt_credential(const char *validate_name, usec_t validate_timestamp, uid_t uid, const struct iovec *input, CredentialFlags flags, struct iovec *ret);
  96
  97 typedef struct PickUpCredential {
  98         const char *credential_prefix;
  99         const char *target_dir;
 100         const char *filename_suffix;
 101 } PickUpCredential;
 102
 103 int pick_up_credentials(const PickUpCredential *table, size_t n_table_entry);