diff options
Diffstat (limited to 'Documentation/keys.txt')
| -rw-r--r-- | Documentation/keys.txt | 59 |
1 files changed, 53 insertions, 6 deletions
diff --git a/Documentation/keys.txt b/Documentation/keys.txt index 51652d39e61c..d5c7a57d1700 100644 --- a/Documentation/keys.txt +++ b/Documentation/keys.txt @@ -170,7 +170,8 @@ The key service provides a number of features besides keys: amount of description and payload space that can be consumed. The user can view information on this and other statistics through procfs - files. + files. The root user may also alter the quota limits through sysctl files + (see the section "New procfs files"). Process-specific and thread-specific keyrings are not counted towards a user's quota. @@ -329,6 +330,27 @@ about the status of the key service: <bytes>/<max> Key size quota +Four new sysctl files have been added also for the purpose of controlling the +quota limits on keys: + + (*) /proc/sys/kernel/keys/root_maxkeys + /proc/sys/kernel/keys/root_maxbytes + + These files hold the maximum number of keys that root may have and the + maximum total number of bytes of data that root may have stored in those + keys. + + (*) /proc/sys/kernel/keys/maxkeys + /proc/sys/kernel/keys/maxbytes + + These files hold the maximum number of keys that each non-root user may + have and the maximum total number of bytes of data that each of those + users may have stored in their keys. + +Root may alter these by writing each new limit as a decimal number string to +the appropriate file. + + =============================== USERSPACE SYSTEM CALL INTERFACE =============================== @@ -711,6 +733,27 @@ The keyctl syscall functions are: The assumed authoritative key is inherited across fork and exec. + (*) Get the LSM security context attached to a key. + + long keyctl(KEYCTL_GET_SECURITY, key_serial_t key, char *buffer, + size_t buflen) + + This function returns a string that represents the LSM security context + attached to a key in the buffer provided. + + Unless there's an error, it always returns the amount of data it could + produce, even if that's too big for the buffer, but it won't copy more + than requested to userspace. If the buffer pointer is NULL then no copy + will take place. + + A NUL character is included at the end of the string if the buffer is + sufficiently big. This is included in the returned count. If no LSM is + in force then an empty string will be returned. + + A process must have view permission on the key for this function to be + successful. + + =============== KERNEL SERVICES =============== @@ -771,7 +814,7 @@ payload contents" for more information. struct key *request_key(const struct key_type *type, const char *description, - const char *callout_string); + const char *callout_info); This is used to request a key or keyring with a description that matches the description specified according to the key type's match function. This @@ -793,24 +836,28 @@ payload contents" for more information. struct key *request_key_with_auxdata(const struct key_type *type, const char *description, - const char *callout_string, + const void *callout_info, + size_t callout_len, void *aux); This is identical to request_key(), except that the auxiliary data is - passed to the key_type->request_key() op if it exists. + passed to the key_type->request_key() op if it exists, and the callout_info + is a blob of length callout_len, if given (the length may be 0). (*) A key can be requested asynchronously by calling one of: struct key *request_key_async(const struct key_type *type, const char *description, - const char *callout_string); + const void *callout_info, + size_t callout_len); or: struct key *request_key_async_with_auxdata(const struct key_type *type, const char *description, - const char *callout_string, + const char *callout_info, + size_t callout_len, void *aux); which are asynchronous equivalents of request_key() and |