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ELFCTL(1)		     General Commands Manual		       ELFCTL(1)

NAME
     elfctl -- change an ELF binary's feature control note

SYNOPSIS
     elfctl [-h | --help] [-i] [-l] [-e featurelist] file ...

DESCRIPTION
     The elfctl utility modifies feature flags in the feature control note in an
     ELF binary.

     The options are as follows:

     -h | --help
	     Print a usage message and exit.

     -i      Ignore unknown feature flags in featurelist.

     -l      List known ELF feature flags.

     -e featurelist
	     Edit  features  from  the	given  comma separated list featurelist.
	     featurelist starts with one of the three operations: "+" to turn on
	     the features, "-" to turn off the features, "=" to only turn on the
	     given features.  A comma separated list of feature names or numeric
	     values follows the operation.

     If -e is not specified elfctl displays the status of each	feature  in  the
     ELF note in each file ....

EXIT STATUS
     Exit  status is 0 on success, and 1 if the command fails if a file does not
     exist, is too short, or fails to find or edit features note.

EXAMPLES
     The following is an example of a typical usage of the elfctl command:

	   elfctl file
	   elfctl -e +noaslr file

     Features may be specified as numerical values:

	   elfctl -e =0x0001,0x0004 file

     Features may also be specified as a single combined value:

	   elfctl -e =0x5 file

NOTES
     On amd64, on a machine with LA57 (5-level paging) mode  supported	and  en-
     abled,  if both la57 and la48 feature flags are specified, the la57 feature
     has priority over la48.  The vm.pmap.prefer_uva_la48 sysctl MIB defines the
     default user address space size for binaries which do  not  set  either  of
     these flags.

SEE ALSO
     mitigations(7)

HISTORY
     elfctl first appeared in FreeBSD 12.2.

AUTHORS
     elfctl  was  written by Bora Ozarslan borako.ozarslan@gmail.com under spon-
     sorship from the FreeBSD Foundation.

FreeBSD ports 15.1		 October 5, 2023		       ELFCTL(1)

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<https://man.freebsd.org/cgi/man.cgi?query=elfctl&sektion=1&manpath=FreeBSD+15.1-RELEASE+and+Ports>

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