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Do we need more robust archeticture protection #1356

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laokz opened this issue Aug 26, 2023 · 4 comments
Open

Do we need more robust archeticture protection #1356

laokz opened this issue Aug 26, 2023 · 4 comments
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@jpoimboe

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@laokz
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laokz commented Aug 26, 2023

I noticed that there are many places using relocation types without #ifdef architecture protection, such as in create-diff-object.c:

	return (rela_toc && rela_toc->sym->type == STT_FUNC &&
		!rela_toc->sym->parent &&
		rela_toc->addend == (int)rela_toc->sym->sym.st_value &&
		(rela->type == R_X86_64_32S ||
		rela->type == R_PPC64_TOC16_HA ||
		rela->type == R_PPC64_TOC16_LO_DS));

All architectures relocation types use same number space. R_X86_64_32S value is 11. This value for PPC is R_PPC_REL14, for arm is R_ARM_THM_PC8. Could this break the code?
@jpoimboe
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Good point! We definitely need to fix that.

@joe-lawrence
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Just a heads up, conditionally building code around #ifdef <arch> works against (eventually) cross-building/testing kpatches. I would think the correct thing to do would be the include the source/target along with the relocation enum check.

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This issue has been open for 30 days with no activity and no assignee. It will be closed in 7 days unless a comment is added.

@github-actions github-actions bot added the stale label Sep 28, 2023
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github-actions bot commented Oct 5, 2023

This issue was closed because it was inactive for 7 days after being marked stale.

@github-actions github-actions bot closed this as completed Oct 5, 2023
@jpoimboe jpoimboe self-assigned this Oct 5, 2023
@jpoimboe jpoimboe removed the stale label Oct 5, 2023
@jpoimboe jpoimboe reopened this Oct 5, 2023
swine added a commit to swine/kpatch that referenced this issue May 31, 2024
@swine
avoid reloc-type collisions on elf.h constants
aa69a14 
Do we need more robust architecture protection (Issue dynup#1356)

The elf.h reloc-type constants are not unique across archs
  #define R_PPC64_REL24           10      /* PC relative 26 bit */
  #define R_X86_64_32             10      /* Direct 32 bit zero extended */
so to avoid any unexpected aliasing, guard all R_arch_type refs
with a check on kelf->arch, or a global default arch set from
the first elf encountered.
mihails-strasuns pushed a commit to mihails-strasuns/kpatch that referenced this issue Jun 14, 2024
@swine
avoid reloc-type collisions on elf.h constants
5fa025a 
Do we need more robust architecture protection (Issue dynup#1356)

The elf.h reloc-type constants are not unique across archs
  #define R_PPC64_REL24           10      /* PC relative 26 bit */
  #define R_X86_64_32             10      /* Direct 32 bit zero extended */
so to avoid any unexpected aliasing, guard all R_arch_type refs
with a check on kelf->arch, or a global default arch set from
the first elf encountered.
mihails-strasuns pushed a commit to mihails-strasuns/kpatch that referenced this issue Sep 5, 2024
@swine
avoid reloc-type collisions on elf.h constants
e0b20c9 
Do we need more robust architecture protection (Issue dynup#1356)

The elf.h reloc-type constants are not unique across archs
  #define R_PPC64_REL24           10      /* PC relative 26 bit */
  #define R_X86_64_32             10      /* Direct 32 bit zero extended */
so to avoid any unexpected aliasing, guard all R_arch_type refs
with a check on kelf->arch, or a global default arch set from
the first elf encountered.
joe-lawrence pushed a commit to joe-lawrence/kpatch that referenced this issue Oct 10, 2024
@swine @joe-lawrence
create-diff-object: avoid reloc-type collisions on elf.h constants
e03ef59 
The elf.h reloc-type constants are not unique across archs, for example:

  #define R_PPC64_REL24           10      /* PC relative 26 bit */
  #define R_X86_64_32             10      /* Direct 32 bit zero extended */

so to avoid any unexpected aliasing, guard all R_arch_type refs with a
check on kelf->arch, or a global default arch set from the first elf
encountered.

Closes: dynup#1356 ("Do we need more robust archeticture protection")
Signed-off-by: Pete Swain <[email protected]>
Signed-off-by: Mihails Strasuns <[email protected]>
Signed-off-by: Joe Lawrence <[email protected]>
joe-lawrence pushed a commit to joe-lawrence/kpatch that referenced this issue Oct 15, 2024
@swine @joe-lawrence
create-diff-object: avoid reloc-type collisions on elf.h constants
3c4dbe2 
The elf.h reloc-type constants are not unique across archs, for example:

  #define R_PPC64_REL24           10      /* PC relative 26 bit */
  #define R_X86_64_32             10      /* Direct 32 bit zero extended */

so to avoid any unexpected aliasing, guard all R_arch_type refs with a
check on kelf->arch, or a global default arch set from the first elf
encountered.

Closes: dynup#1356 ("Do we need more robust archeticture protection")
Signed-off-by: Pete Swain <[email protected]>
Signed-off-by: Mihails Strasuns <[email protected]>
Signed-off-by: Joe Lawrence <[email protected]>
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@jpoimboe @joe-lawrence @laokz