EACCES The requested operation wasn't permitted.
EAGAIN operation was KEYCTL_DH_COMPUTE and there was an error
during crypto module initialization.
EDEADLK
operation was KEYCTL_LINK and the requested link would
result in a cycle.
EDEADLK
operation was KEYCTL_RESTRICT_KEYRING and the requested
keyring restriction would result in a cycle.
EDQUOT The key quota for the caller's user would be exceeded by
creating a key or linking it to the keyring.
EEXIST operation was KEYCTL_RESTRICT_KEYRING and keyring provided
in arg2 argument already has a restriction set.
EFAULT operation was KEYCTL_DH_COMPUTE and one of the following
has failed:
• copying of the struct keyctl_dh_params, provided in the
arg2 argument, from user space;
• copying of the struct keyctl_kdf_params, provided in
the non-NULL arg5 argument, from user space (in case
kernel supports performing KDF operation on DH
operation result);
• copying of data pointed by the hashname field of the
struct keyctl_kdf_params from user space;
• copying of data pointed by the otherinfo field of the
struct keyctl_kdf_params from user space if the
otherinfolen field was nonzero;
• copying of the result to user space.
EINVAL operation was KEYCTL_SETPERM and an invalid permission bit
was specified in arg3.
EINVAL operation was KEYCTL_SEARCH and the size of the
description in arg4 (including the terminating null byte)
exceeded 4096 bytes.
EINVAL size of the string (including the terminating null byte)
specified in arg3 (the key type) or arg4 (the key
description) exceeded the limit (32 bytes and 4096 bytes
respectively).
EINVAL (Linux kernels before 4.12)
operation was KEYCTL_DH_COMPUTE, argument arg5 was non-
NULL.
EINVAL operation was KEYCTL_DH_COMPUTE And the digest size of the
hashing algorithm supplied is zero.
EINVAL operation was KEYCTL_DH_COMPUTE and the buffer size
provided is not enough to hold the result. Provide 0 as a
buffer size in order to obtain the minimum buffer size.
EINVAL operation was KEYCTL_DH_COMPUTE and the hash name provided
in the hashname field of the struct keyctl_kdf_params
pointed by arg5 argument is too big (the limit is
implementation-specific and varies between kernel
versions, but it is deemed big enough for all valid
algorithm names).
EINVAL operation was KEYCTL_DH_COMPUTE and the __spare field of
the struct keyctl_kdf_params provided in the arg5 argument
contains nonzero values.
EKEYEXPIRED
An expired key was found or specified.
EKEYREJECTED
A rejected key was found or specified.
EKEYREVOKED
A revoked key was found or specified.
ELOOP operation was KEYCTL_LINK and the requested link would
cause the maximum nesting depth for keyrings to be
exceeded.
EMSGSIZE
operation was KEYCTL_DH_COMPUTE and the buffer length
exceeds KEYCTL_KDF_MAX_OUTPUT_LEN (which is 1024
currently) or the otherinfolen field of the struct
keyctl_kdf_parms passed in arg5 exceeds
KEYCTL_KDF_MAX_OI_LEN (which is 64 currently).
ENFILE (Linux kernels before 3.13)
operation was KEYCTL_LINK and the keyring is full.
(Before Linux 3.13, the available space for storing
keyring links was limited to a single page of memory;
since Linux 3.13, there is no fixed limit.)
ENOENT operation was KEYCTL_UNLINK and the key to be unlinked
isn't linked to the keyring.
ENOENT operation was KEYCTL_DH_COMPUTE and the hashing algorithm
specified in the hashname field of the struct
keyctl_kdf_params pointed by arg5 argument hasn't been
found.
ENOENT operation was KEYCTL_RESTRICT_KEYRING and the type
provided in arg3 argument doesn't support setting key
linking restrictions.
ENOKEY No matching key was found or an invalid key was specified.
ENOKEY The value KEYCTL_GET_KEYRING_ID was specified in
operation, the key specified in arg2 did not exist, and
arg3 was zero (meaning don't create the key if it didn't
exist).
ENOMEM One of kernel memory allocation routines failed during the
execution of the syscall.
ENOTDIR
A key of keyring type was expected but the ID of a key
with a different type was provided.
EOPNOTSUPP
operation was KEYCTL_READ and the key type does not
support reading (e.g., the type is "login").
EOPNOTSUPP
operation was KEYCTL_UPDATE and the key type does not
support updating.
EOPNOTSUPP
operation was KEYCTL_RESTRICT_KEYRING, the type provided
in arg3 argument was "asymmetric", and the key specified
in the restriction specification provided in arg4 has type
other than "asymmetric" or "keyring".
EPERM operation was KEYCTL_GET_PERSISTENT, arg2 specified a UID
other than the calling thread's real or effective UID, and
the caller did not have the CAP_SETUID capability.
EPERM operation was KEYCTL_SESSION_TO_PARENT and either: all of
the UIDs (GIDs) of the parent process do not match the
effective UID (GID) of the calling process; the UID of the
parent's existing session keyring or the UID of the
caller's session keyring did not match the effective UID
of the caller; the parent process is not single-thread; or
the parent process is init(1) or a kernel thread.
ETIMEDOUT
operation was KEYCTL_DH_COMPUTE and the initialization of
crypto modules has timed out.
