man2/add_key.2

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  10 .\"
  11 .TH ADD_KEY 2 2016-07-17 Linux "Linux Key Management Calls"
  12 .SH NAME
  13 add_key \- add a key to the kernel's key management facility
  14 .SH SYNOPSIS
  15 .nf
  16 .B #include <keyutils.h>
  17 .sp
  18 .BI "key_serial_t add_key(const char *" type ", const char *" description ,
  19 .BI "                     const void *" payload ", size_t " plen ,
  20 .BI "                     key_serial_t " keyring ");"
  21 .fi
  22
  23 No glibc wrapper is provided for this system call; see NOTES.
  24 .SH DESCRIPTION
  25 .BR add_key ()
  26 creates or updates a key of the given
  27 .I type
  28 and
  29 .IR description ,
  30 instantiates it with the
  31 .I payload
  32 of length
  33 .IR plen ,
  34 attaches it to the nominated
  35 .IR keyring ,
  36 and return the key's serial number.
  37 .P
  38 The key type may reject the data if it is in the wrong format or
  39 is in some other way invalid.
  40 .P
  41 If the destination
  42 .I keyring
  43 already contains a key that matches the specified
  44 .IR type
  45 and
  46 .IR description ,
  47 then, if the key type supports it, that key will be updated rather than a new
  48 key being created; if not, a new key will be created and it will displace the
  49 link to the extant key from the keyring.
  50 .P
  51 The destination
  52 .I keyring
  53 serial number may be that of a valid keyring for which the caller has
  54 .I write
  55 permission, or it may be one of the following special keyring IDs:
  56 .TP
  57 .B KEY_SPEC_THREAD_KEYRING
  58 This specifies the caller's thread-specific keyring.
  59 .TP
  60 .B KEY_SPEC_PROCESS_KEYRING
  61 This specifies the caller's process-specific keyring.
  62 .TP
  63 .B KEY_SPEC_SESSION_KEYRING
  64 This specifies the caller's session-specific keyring.
  65 .TP
  66 .B KEY_SPEC_USER_KEYRING
  67 This specifies the caller's UID-specific keyring.
  68 .TP
  69 .B KEY_SPEC_USER_SESSION_KEYRING
  70 This specifies the caller's UID-session keyring.
  71 .SS Key types
  72 There are a number of key types available in the core key management code, and
  73 these can be specified to this function:
  74 .TP
  75 .B \*(lquser\*(rq
  76 Keys of the user-defined key type may contain a blob of arbitrary data, and the
  77 .I description
  78 may be any valid string, though it is preferred that the description be
  79 prefixed with a string representing the service to which the key is of interest
  80 and a colon (for instance
  81 .RB \*(lq afs:mykey \*(rq).
  82 .TP
  83 .B \*(lqkeyring\*(rq
  84 Keyrings are special key types that may contain links to sequences of other
  85 keys of any type.
  86 If this interface is used to create a keyring, then a NULL
  87 .I payload
  88 should be specified, and
  89 .I plen
  90 should be zero.
  91 .SH RETURN VALUE
  92 On success,
  93 .BR add_key ()
  94 returns the serial number of the key it created or updated.
  95 On error, \-1 is returned and
  96 .I errno
  97 is set to indicate the cause of the error.
  98 .SH ERRORS
  99 .TP
 100 .B EACCES
 101 The keyring wasn't available for modification by the user.
 102 .TP
 103 .B EINVAL
 104 The payload data was invalid.
 105 .TP
 106 .B EKEYEXPIRED
 107 The keyring has expired.
 108 .TP
 109 .B EKEYREVOKED
 110 The keyring has been revoked.
 111 .TP
 112 .B ENOKEY
 113 The keyring doesn't exist.
 114 .TP
 115 .B ENOMEM
 116 Insufficient memory to create a key.
 117 .TP
 118 .B EDQUOT
 119 The key quota for this user would be exceeded by creating this key or linking
 120 it to the keyring.
 121 .SH VERSIONS
 122 This system call first appeared in Linux 2.6.11.
 123 .SH CONFORMING TO
 124 This system call is a nonstandard Linux extension.
 125 .SH NOTES
 126 No wrapper for this system call is provided in glibc.
 127 A wrapper is provided in the
 128 .IR libkeyutils
 129 package.
 130 When employing the wrapper in that library, link with
 131 .IR \-lkeyutils .
 132 .SH SEE ALSO
 133 .BR keyctl (1),
 134 .BR keyctl (2),
 135 .BR request_key (2),
 136 .BR keyctl (3),
 137 .BR keyutils (7),
 138 .BR keyrings (7),
 139 .BR persistent-keyring (7),
 140 .BR process-keyring (7),
 141 .BR session-keyring (7),
 142 .BR thread-keyring (7),
 143 .BR user-keyring (7),
 144 .BR user-session-keyring (7)
 145
 146 The kernel source files
 147 .IR Documentation/security/keys.txt
 148 and
 149 .IR Documentation/security/keys-request-key.txt .