PR_PAC_RESET_KEYS(2const) — Linux manual page

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | STANDARDS | HISTORY | CAVEATS | SEE ALSO | COLOPHON

PR_PAC_RESET_KEYS(2const)                      PR_PAC_RESET_KEYS(2const)

NAME         top

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

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #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         top

       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         top

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

ERRORS         top

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

STANDARDS         top

       Linux.  arm64 only.

HISTORY         top

       Linux 5.0 (arm64).

CAVEATS         top

       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         top

       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).

COLOPHON         top

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Linux man-pages 6.9.1          2024-06-01      PR_PAC_RESET_KEYS(2const)

Pages that refer to this page: prctl(2)