ExecutableStacks

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 * fglrx-installer  * [[https://bugs.launchpad.net/bugs/409440|fglrx-installer]]

There are still some programs that have executable stack regions, which results in their being vulnerable to exploitation via stack memory. There are only a few very rare situations where executable stacks are actually desired, and are usually the result of lacking flags in assembly code or using nested functions (which are generally avoidable).

  • check an ELF binary: "readelf -lW $BIN | grep GNU_STACK" shows with "E" flag.

  • fix source by adding flags to assembler: .section        .note.GNU-stack, "", @progbits

  • Gentoo write-up about exec stack handling: http://www.gentoo.org/proj/en/hardened/gnu-stack.xml

  • -Wl,-z,noexecstack will change the behavior of compiler's asm-without-stack-markings defaults.

Main/Restricted Packages

Originally generated from the ELF files with executable stacks in Karmic main.

Fixed

Nested Functions

Uses Nested Functions which compiler generates as trampolines on the stack.

Trampolines

  • klibc (setjmp implementation)
  • kexec-tools (statically linked against klibc)

Shipped Precompiled Binary

  • fglrx-installer

  • nvidia-graphics-drivers-173
  • nvidia-graphics-drivers-180
  • nvidia-graphics-drivers-71
  • nvidia-graphics-drivers-96

Unclassified

  • icon
  • john
  • link-grammar
  • mbr
  • memtest86+
  • openjdk-6

Fedora Patches

SecurityTeam/Roadmap/ExecutableStacks (last edited 2017-08-22 14:25:31 by jdstrand)