NAME

       PR_PAC_RESET_KEYS - reset the calling thread's pointer authentication code keys

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <linux/prctl.h>  /* Definition of PR_* constants */
       #include <sys/prctl.h>

       int prctl(PR_PAC_RESET_KEYS, unsigned long keys, 0L, 0L, 0L);

DESCRIPTION

       Securely  reset  the thread's pointer authentication keys to fresh random values generated
       by the kernel.

       The set of keys to be reset is specified by keys, which must be a logical OR  of  zero  or
       more of the following:

       PR_PAC_APIAKEY
              instruction authentication key A

       PR_PAC_APIBKEY
              instruction authentication key B

       PR_PAC_APDAKEY
              data authentication key A

       PR_PAC_APDBKEY
              data authentication key B

       PR_PAC_APGAKEY
              generic authentication “A” key.

              (Yes folks, there really is no generic B key.)

       As  a special case, if keys is zero, then all the keys are reset.  Since new keys could be
       added in future, this is the recommended way to completely wipe  the  existing  keys  when
       establishing a clean execution context.

       There  is  no  need  to  use PR_PAC_RESET_KEYS in preparation for calling execve(2), since
       execve(2) resets all the pointer authentication keys.

RETURN VALUE

       On success, 0 is returned.  On error, -1 is returned, and errno is  set  to  indicate  the
       error.

ERRORS

       EINVAL keys contains set bits that are invalid or unsupported on this platform.

STANDARDS

       Linux.  arm64 only.

HISTORY

       Linux 5.0 (arm64).

CAVEATS

       Because  the  compiler  or  run-time  environment  may be using some or all of the keys, a
       successful PR_PAC_RESET_KEYS may crash the calling process.  The conditions for  using  it
       safely are complex and system-dependent.  Don't use it unless you know what you are doing.

SEE ALSO

       prctl(2)

       For       more       information,       see       the       kernel       source       file
       Documentation/arm64/pointer-authentication.rst                                         (or
       Documentation/arm64/pointer-authentication.txt before Linux 5.3).