инструмент для установки, очистки или запроса флага исполняемого стека двоичных файлов ELF и разделяемых библиотек (tool to set, clear, or query executable stack flag of ELF binaries and shared libraries)
Имя (Name)
execstack - tool to set, clear, or query executable stack flag of
ELF binaries and shared libraries
Синопсис (Synopsis)
execstack [OPTION...] [FILES]
Описание (Description)
execstack
is a program which sets, clears, or queries executable
stack flag of ELF binaries and shared libraries. Linux has in
the past allowed execution of instructions on the stack and there
are lots of binaries and shared libraries assuming this
behaviour. Furthermore, GCC trampoline code for e.g. nested
functions requires executable stack on many architectures. To
avoid breaking binaries and shared libraries which need
executable stack, ELF binaries and shared libraries now can be
marked as requiring executable stack or not requiring it. This
marking is done through the p_flags field in the PT_GNU_STACK
program header entry. If the marking is missing, kernel or
dynamic linker need to assume it might need executable stack.
The marking is done automatically by recent GCC versions (objects
using trampolines on the stack are marked as requiring executable
stack, all other newly built objects are marked as not requiring
it) and linker collects these markings into marking of the whole
binary or shared library. The user can override this at assembly
time (through --execstack
or --noexecstack
assembler options), at
link time (through -z execstack
or -z noexecstack
linker options)
and using the execstack
tool also on an already linker binary or
shared library. This tool is especially useful for third party
shared libraries where it is known that they don't need
executable stack or testing proves it.
Параметры (Options)
-s --set-execstack
Mark binary or shared library as requiring executable
stack.
-c --clear-execstack
Mark binary or shared library as not requiring executable
stack.
-q --query
Query executable stack marking of binaries and shared
libraries. For each file it prints either -
when
executable stack is not required, X
when executable stack
is required or ?
when it is unknown whether the object
requires or doesn't require executable stack (the marking
is missing).
-V
Print execstack
version and exit.
-? --help
Print help message.
--usage
Print a short usage message.
Аргументы (Arguments)
Command line arguments should be names of ELF binaries and shared
libraries which should be modified or queried.
Примеры (Examples)
# execstack -s ~/lib/libfoo.so.1
will mark ~/lib/libfoo.so.1 as requiring executable stack.
# execstack -c ~/bin/bar
will mark ~/bin/bar as not requiring executable stack.
# execstack -q ~/lib/libfoo.so.1 ~/bin/bar
will query executable stack marking of the given files.
Смотри также (See also)
ld.so(8).
Ошибки (баги) (Bugs)
execstack
doesn't support yet marking of executables if they do
not have PT_GNU_STACK program header entry nor they have room for
program segment header table growth.