Commit 9fb4c525 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching 

Pull livepatching updates from Jiri Kosina:

 - simplifications and improvements for issues Peter Ziljstra found
   during his previous work on W^X cleanups.

   This allows us to remove livepatch arch-specific .klp.arch sections
   and add proper support for jump labels in patched code.

   Also, this patchset removes the last module_disable_ro() usage in the
   tree.

   Patches from Josh Poimboeuf and Peter Zijlstra

 - a few other minor cleanups

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
  MAINTAINERS: add lib/livepatch to LIVE PATCHING
  livepatch: add arch-specific headers to MAINTAINERS
  livepatch: Make klp_apply_object_relocs static
  MAINTAINERS: adjust to livepatch .klp.arch removal
  module: Make module_enable_ro() static again
  x86/module: Use text_mutex in apply_relocate_add()
  module: Remove module_disable_ro()
  livepatch: Remove module_disable_ro() usage
  x86/module: Use text_poke() for late relocations
  s390/module: Use s390_kernel_write() for late relocations
  s390: Change s390_kernel_write() return type to match memcpy()
  livepatch: Prevent module-specific KLP rela sections from referencing vmlinux symbols
  livepatch: Remove .klp.arch
  livepatch: Apply vmlinux-specific KLP relocations early
  livepatch: Disallow vmlinux.ko
parents a789d5f8 f55d9895

Documentation/livepatch/module-elf-format.rst

+2 −13
Original line number Diff line number Diff line
@@ -14,8 +14,7 @@ This document outlines the Elf format requirements that livepatch modules must f 
   4. Livepatch symbols

      4.1 A livepatch module's symbol table

      4.2 Livepatch symbol format

   5. Architecture-specific sections

   6. Symbol table and Elf section access

   5. Symbol table and Elf section access



1. Background and motivation

============================
@@ -298,17 +297,7 @@ Examples: 
  Note that the 'Ndx' (Section index) for these symbols is SHN_LIVEPATCH (0xff20).

  "OS" means OS-specific.



5. Architecture-specific sections

=================================

Architectures may override arch_klp_init_object_loaded() to perform

additional arch-specific tasks when a target module loads, such as applying

arch-specific sections. On x86 for example, we must apply per-object

.altinstructions and .parainstructions sections when a target module loads.

These sections must be prefixed with ".klp.arch.$objname." so that they can

be easily identified when iterating through a patch module's Elf sections

(See arch/x86/kernel/livepatch.c for a complete example).



6. Symbol table and Elf section access

5. Symbol table and Elf section access

======================================

A livepatch module's symbol table is accessible through module->symtab.

MAINTAINERS

+3 −1
Original line number Diff line number Diff line
@@ -9936,10 +9936,12 @@ S: Maintained 
T:	git git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching.git

F:	Documentation/ABI/testing/sysfs-kernel-livepatch

F:	Documentation/livepatch/

F:	arch/powerpc/include/asm/livepatch.h

F:	arch/s390/include/asm/livepatch.h

F:	arch/x86/include/asm/livepatch.h

F:	arch/x86/kernel/livepatch.c

F:	include/linux/livepatch.h

F:	kernel/livepatch/

F:	lib/livepatch/

F:	samples/livepatch/

F:	tools/testing/selftests/livepatch/

































arch/s390/include/asm/uaccess.h



+1
−1






























Original line number
Diff line number
Diff line








@@ -276,6 +276,6 @@ static inline unsigned long __must_check clear_user(void __user *to, unsigned lo













}































int copy_to_user_real(void __user *dest, void *src, unsigned long count);













void s390_kernel_write(void *dst, const void *src, size_t size);













void *s390_kernel_write(void *dst, const void *src, size_t size);































#endif /* __S390_UACCESS_H */
























arch/s390/kernel/module.c



+88
−59






























Original line number
Diff line number
Diff line








@@ -19,6 +19,7 @@













#include <linux/kasan.h>















#include <linux/moduleloader.h>















#include <linux/bug.h>













#include <linux/memory.h>















#include <asm/alternative.h>















#include <asm/nospec-branch.h>















#include <asm/facility.h>










@@ -174,10 +175,12 @@ int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,













}































static int apply_rela_bits(Elf_Addr loc, Elf_Addr val,













			   int sign, int bits, int shift)













			   int sign, int bits, int shift,













			   void *(*write)(void *dest, const void *src, size_t len))















{















	unsigned long umax;















	long min, max;













	void *dest = (void *)loc;































	if (val & ((1UL << shift) - 1))















		return -ENOEXEC;









@@ -194,26 +197,33 @@ static int apply_rela_bits(Elf_Addr loc, Elf_Addr val,













			return -ENOEXEC;















	}





























	if (bits == 8)













		*(unsigned char *) loc = val;













	else if (bits == 12)













		*(unsigned short *) loc = (val & 0xfff) |













	if (bits == 8) {













		unsigned char tmp = val;













		write(dest, &tmp, 1);













	} else if (bits == 12) {













		unsigned short tmp = (val & 0xfff) |















			(*(unsigned short *) loc & 0xf000);













	else if (bits == 16)













		*(unsigned short *) loc = val;













	else if (bits == 20)













		*(unsigned int *) loc = (val & 0xfff) << 16 |













			(val & 0xff000) >> 4 |













			(*(unsigned int *) loc & 0xf00000ff);













	else if (bits == 32)













		*(unsigned int *) loc = val;













	else if (bits == 64)













		*(unsigned long *) loc = val;













		write(dest, &tmp, 2);













	} else if (bits == 16) {













		unsigned short tmp = val;













		write(dest, &tmp, 2);













	} else if (bits == 20) {













		unsigned int tmp = (val & 0xfff) << 16 |













			(val & 0xff000) >> 4 | (*(unsigned int *) loc & 0xf00000ff);













		write(dest, &tmp, 4);













	} else if (bits == 32) {













		unsigned int tmp = val;













		write(dest, &tmp, 4);













	} else if (bits == 64) {













		unsigned long tmp = val;













		write(dest, &tmp, 8);













	}















	return 0;















}































static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,













		      const char *strtab, struct module *me)













		      const char *strtab, struct module *me,













		      void *(*write)(void *dest, const void *src, size_t len))















{















	struct mod_arch_syminfo *info;















	Elf_Addr loc, val;










@@ -241,17 +251,17 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,













	case R_390_64:		/* Direct 64 bit.  */















		val += rela->r_addend;















		if (r_type == R_390_8)













			rc = apply_rela_bits(loc, val, 0, 8, 0);













			rc = apply_rela_bits(loc, val, 0, 8, 0, write);















		else if (r_type == R_390_12)













			rc = apply_rela_bits(loc, val, 0, 12, 0);













			rc = apply_rela_bits(loc, val, 0, 12, 0, write);















		else if (r_type == R_390_16)













			rc = apply_rela_bits(loc, val, 0, 16, 0);













			rc = apply_rela_bits(loc, val, 0, 16, 0, write);















		else if (r_type == R_390_20)













			rc = apply_rela_bits(loc, val, 1, 20, 0);













			rc = apply_rela_bits(loc, val, 1, 20, 0, write);















		else if (r_type == R_390_32)













			rc = apply_rela_bits(loc, val, 0, 32, 0);













			rc = apply_rela_bits(loc, val, 0, 32, 0, write);















		else if (r_type == R_390_64)













			rc = apply_rela_bits(loc, val, 0, 64, 0);













			rc = apply_rela_bits(loc, val, 0, 64, 0, write);















		break;















	case R_390_PC16:	/* PC relative 16 bit.  */















	case R_390_PC16DBL:	/* PC relative 16 bit shifted by 1.  */









@@ -260,15 +270,15 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,













	case R_390_PC64:	/* PC relative 64 bit.	*/















		val += rela->r_addend - loc;















		if (r_type == R_390_PC16)













			rc = apply_rela_bits(loc, val, 1, 16, 0);













			rc = apply_rela_bits(loc, val, 1, 16, 0, write);















		else if (r_type == R_390_PC16DBL)













			rc = apply_rela_bits(loc, val, 1, 16, 1);













			rc = apply_rela_bits(loc, val, 1, 16, 1, write);















		else if (r_type == R_390_PC32DBL)













			rc = apply_rela_bits(loc, val, 1, 32, 1);













			rc = apply_rela_bits(loc, val, 1, 32, 1, write);















		else if (r_type == R_390_PC32)













			rc = apply_rela_bits(loc, val, 1, 32, 0);













			rc = apply_rela_bits(loc, val, 1, 32, 0, write);















		else if (r_type == R_390_PC64)













			rc = apply_rela_bits(loc, val, 1, 64, 0);













			rc = apply_rela_bits(loc, val, 1, 64, 0, write);















		break;















	case R_390_GOT12:	/* 12 bit GOT offset.  */















	case R_390_GOT16:	/* 16 bit GOT offset.  */









@@ -283,33 +293,33 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,













	case R_390_GOTPLT64:	/* 64 bit offset to jump slot.	*/















	case R_390_GOTPLTENT:	/* 32 bit rel. offset to jump slot >> 1. */















		if (info->got_initialized == 0) {













			Elf_Addr *gotent;



























			gotent = me->core_layout.base + me->arch.got_offset +













			Elf_Addr *gotent = me->core_layout.base +













					   me->arch.got_offset +















					   info->got_offset;













			*gotent = val;



























			write(gotent, &val, sizeof(*gotent));















			info->got_initialized = 1;















		}















		val = info->got_offset + rela->r_addend;















		if (r_type == R_390_GOT12 ||















		    r_type == R_390_GOTPLT12)













			rc = apply_rela_bits(loc, val, 0, 12, 0);













			rc = apply_rela_bits(loc, val, 0, 12, 0, write);















		else if (r_type == R_390_GOT16 ||















			 r_type == R_390_GOTPLT16)













			rc = apply_rela_bits(loc, val, 0, 16, 0);













			rc = apply_rela_bits(loc, val, 0, 16, 0, write);















		else if (r_type == R_390_GOT20 ||















			 r_type == R_390_GOTPLT20)













			rc = apply_rela_bits(loc, val, 1, 20, 0);













			rc = apply_rela_bits(loc, val, 1, 20, 0, write);















		else if (r_type == R_390_GOT32 ||















			 r_type == R_390_GOTPLT32)













			rc = apply_rela_bits(loc, val, 0, 32, 0);













			rc = apply_rela_bits(loc, val, 0, 32, 0, write);















		else if (r_type == R_390_GOT64 ||















			 r_type == R_390_GOTPLT64)













			rc = apply_rela_bits(loc, val, 0, 64, 0);













			rc = apply_rela_bits(loc, val, 0, 64, 0, write);















		else if (r_type == R_390_GOTENT ||















			 r_type == R_390_GOTPLTENT) {















			val += (Elf_Addr) me->core_layout.base - loc;













			rc = apply_rela_bits(loc, val, 1, 32, 1);













			rc = apply_rela_bits(loc, val, 1, 32, 1, write);















		}















		break;















	case R_390_PLT16DBL:	/* 16 bit PC rel. PLT shifted by 1.  */









@@ -320,25 +330,29 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,













	case R_390_PLTOFF32:	/* 32 bit offset from GOT to PLT. */















	case R_390_PLTOFF64:	/* 16 bit offset from GOT to PLT. */















		if (info->plt_initialized == 0) {













			unsigned int *ip;













			ip = me->core_layout.base + me->arch.plt_offset +













			unsigned int insn[5];













			unsigned int *ip = me->core_layout.base +













					   me->arch.plt_offset +















					   info->plt_offset;













			ip[0] = 0x0d10e310;	/* basr 1,0  */













			ip[1] = 0x100a0004;	/* lg	1,10(1) */



























			insn[0] = 0x0d10e310;	/* basr 1,0  */













			insn[1] = 0x100a0004;	/* lg	1,10(1) */















			if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable) {















				unsigned int *ij;















				ij = me->core_layout.base +















					me->arch.plt_offset +















					me->arch.plt_size - PLT_ENTRY_SIZE;













				ip[2] = 0xa7f40000 +	/* j __jump_r1 */













				insn[2] = 0xa7f40000 +	/* j __jump_r1 */















					(unsigned int)(u16)















					(((unsigned long) ij - 8 -















					  (unsigned long) ip) / 2);















			} else {













				ip[2] = 0x07f10000;	/* br %r1 */













				insn[2] = 0x07f10000;	/* br %r1 */















			}













			ip[3] = (unsigned int) (val >> 32);













			ip[4] = (unsigned int) val;













			insn[3] = (unsigned int) (val >> 32);













			insn[4] = (unsigned int) val;



























			write(ip, insn, sizeof(insn));















			info->plt_initialized = 1;















		}















		if (r_type == R_390_PLTOFF16 ||









@@ -357,17 +371,17 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,













			val += rela->r_addend - loc;















		}















		if (r_type == R_390_PLT16DBL)













			rc = apply_rela_bits(loc, val, 1, 16, 1);













			rc = apply_rela_bits(loc, val, 1, 16, 1, write);















		else if (r_type == R_390_PLTOFF16)













			rc = apply_rela_bits(loc, val, 0, 16, 0);













			rc = apply_rela_bits(loc, val, 0, 16, 0, write);















		else if (r_type == R_390_PLT32DBL)













			rc = apply_rela_bits(loc, val, 1, 32, 1);













			rc = apply_rela_bits(loc, val, 1, 32, 1, write);















		else if (r_type == R_390_PLT32 ||















			 r_type == R_390_PLTOFF32)













			rc = apply_rela_bits(loc, val, 0, 32, 0);













			rc = apply_rela_bits(loc, val, 0, 32, 0, write);















		else if (r_type == R_390_PLT64 ||















			 r_type == R_390_PLTOFF64)













			rc = apply_rela_bits(loc, val, 0, 64, 0);













			rc = apply_rela_bits(loc, val, 0, 64, 0, write);















		break;















	case R_390_GOTOFF16:	/* 16 bit offset to GOT.  */















	case R_390_GOTOFF32:	/* 32 bit offset to GOT.  */









@@ -375,20 +389,20 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,













		val = val + rela->r_addend -















			((Elf_Addr) me->core_layout.base + me->arch.got_offset);















		if (r_type == R_390_GOTOFF16)













			rc = apply_rela_bits(loc, val, 0, 16, 0);













			rc = apply_rela_bits(loc, val, 0, 16, 0, write);















		else if (r_type == R_390_GOTOFF32)













			rc = apply_rela_bits(loc, val, 0, 32, 0);













			rc = apply_rela_bits(loc, val, 0, 32, 0, write);















		else if (r_type == R_390_GOTOFF64)













			rc = apply_rela_bits(loc, val, 0, 64, 0);













			rc = apply_rela_bits(loc, val, 0, 64, 0, write);















		break;















	case R_390_GOTPC:	/* 32 bit PC relative offset to GOT. */















	case R_390_GOTPCDBL:	/* 32 bit PC rel. off. to GOT shifted by 1. */















		val = (Elf_Addr) me->core_layout.base + me->arch.got_offset +















			rela->r_addend - loc;















		if (r_type == R_390_GOTPC)













			rc = apply_rela_bits(loc, val, 1, 32, 0);













			rc = apply_rela_bits(loc, val, 1, 32, 0, write);















		else if (r_type == R_390_GOTPCDBL)













			rc = apply_rela_bits(loc, val, 1, 32, 1);













			rc = apply_rela_bits(loc, val, 1, 32, 1, write);















		break;















	case R_390_COPY:















	case R_390_GLOB_DAT:	/* Create GOT entry.  */









@@ -412,9 +426,10 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,













	return 0;















}





























int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,













static int __apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,















		       unsigned int symindex, unsigned int relsec,













		       struct module *me)













		       struct module *me,













		       void *(*write)(void *dest, const void *src, size_t len))















{















	Elf_Addr base;















	Elf_Sym *symtab;









@@ -430,13 +445,27 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,













	n = sechdrs[relsec].sh_size / sizeof(Elf_Rela);































	for (i = 0; i < n; i++, rela++) {













		rc = apply_rela(rela, base, symtab, strtab, me);













		rc = apply_rela(rela, base, symtab, strtab, me, write);















		if (rc)















			return rc;















	}















	return 0;















}





























int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,













		       unsigned int symindex, unsigned int relsec,













		       struct module *me)













{













	bool early = me->state == MODULE_STATE_UNFORMED;













	void *(*write)(void *, const void *, size_t) = memcpy;



























	if (!early)













		write = s390_kernel_write;



























	return __apply_relocate_add(sechdrs, strtab, symindex, relsec, me,













				    write);













}





























int module_finalize(const Elf_Ehdr *hdr,















		    const Elf_Shdr *sechdrs,















		    struct module *me)

































arch/s390/mm/maccess.c



+6
−3






























Original line number
Diff line number
Diff line








@@ -55,19 +55,22 @@ static notrace long s390_kernel_write_odd(void *dst, const void *src, size_t siz













 */















static DEFINE_SPINLOCK(s390_kernel_write_lock);





























void notrace s390_kernel_write(void *dst, const void *src, size_t size)













notrace void *s390_kernel_write(void *dst, const void *src, size_t size)















{













	void *tmp = dst;















	unsigned long flags;















	long copied;































	spin_lock_irqsave(&s390_kernel_write_lock, flags);















	while (size) {













		copied = s390_kernel_write_odd(dst, src, size);













		dst += copied;













		copied = s390_kernel_write_odd(tmp, src, size);













		tmp += copied;















		src += copied;















		size -= copied;















	}















	spin_unlock_irqrestore(&s390_kernel_write_lock, flags);



























	return dst;















}































static int __no_sanitize_address __memcpy_real(void *dest, void *src, size_t count)









































































CRA Git | Maintained and supported by SUSTech CRA and CCSE