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Merge tag 'core_core_updates_for_5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull READ_IMPLIES_EXEC changes from Borislav Petkov:
 "Split the old READ_IMPLIES_EXEC workaround from executable
  PT_GNU_STACK now that toolchains long support PT_GNU_STACK marking and
  there's no need anymore to force modern programs into having all its
  user mappings executable instead of only the stack and the PROT_EXEC
  ones.

  Disable that automatic READ_IMPLIES_EXEC forcing on x86-64 and
  arm64.

  Add tables documenting how READ_IMPLIES_EXEC is handled on x86-64, arm
  and arm64.

  By Kees Cook"

* tag 'core_core_updates_for_5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  arm64/elf: Disable automatic READ_IMPLIES_EXEC for 64-bit address spaces
  arm32/64/elf: Split READ_IMPLIES_EXEC from executable PT_GNU_STACK
  arm32/64/elf: Add tables to document READ_IMPLIES_EXEC
  x86/elf: Disable automatic READ_IMPLIES_EXEC on 64-bit
  x86/elf: Split READ_IMPLIES_EXEC from executable PT_GNU_STACK
  x86/elf: Add table to document READ_IMPLIES_EXEC
This commit is contained in:
Linus Torvalds
2020-06-05 13:45:21 -07:00
parent 7ae77150d9 6e0d6ac5f3
commit ac7b34218a
4 changed files with 71 additions and 6 deletions
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arch/arm64/include/asm/elf.h
+22 -1
View File
@@ -96,7 +96,28 @@
*/
#define elf_check_arch(x) ((x)->e_machine == EM_AARCH64)
#define elf_read_implies_exec(ex,stk) (stk != EXSTACK_DISABLE_X)
/*
* An executable for which elf_read_implies_exec() returns TRUE will
* have the READ_IMPLIES_EXEC personality flag set automatically.
*
* The decision process for determining the results are:
*
*              CPU*: | arm32    | arm64 |
* ELF:              |            |            |
* ---------------------|------------|------------|
* missing PT_GNU_STACK | exec-all   | exec-none  |
* PT_GNU_STACK == RWX  | exec-stack | exec-stack |
* PT_GNU_STACK == RW   | exec-none | exec-none |
*
* exec-all : all PROT_READ user mappings are executable, except when
* backed by files on a noexec-filesystem.
* exec-none : only PROT_EXEC user mappings are executable.
* exec-stack: only the stack and PROT_EXEC user mappings are executable.
*
* *all arm64 CPUs support NX, so there is no "lacks NX" column.
*
*/
#define compat_elf_read_implies_exec(ex, stk) (stk == EXSTACK_DEFAULT)
#define CORE_DUMP_USE_REGSET
#define ELF_EXEC_PAGESIZE PAGE_SIZE