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
This commit is contained in:
Linus Torvalds
commit
9fb4c5250f
13 changed files with 284 additions and 237 deletions
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|
@ -14,8 +14,7 @@ This document outlines the Elf format requirements that livepatch modules must f
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|||
4. Livepatch symbols
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||||
4.1 A livepatch module's symbol table
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4.2 Livepatch symbol format
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5. Architecture-specific sections
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||||
6. Symbol table and Elf section access
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||||
5. Symbol table and Elf section access
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||||
|
||||
1. Background and motivation
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||||
============================
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@ -298,17 +297,7 @@ Examples:
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|||
Note that the 'Ndx' (Section index) for these symbols is SHN_LIVEPATCH (0xff20).
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"OS" means OS-specific.
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||||
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5. Architecture-specific sections
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||||
=================================
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Architectures may override arch_klp_init_object_loaded() to perform
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additional arch-specific tasks when a target module loads, such as applying
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arch-specific sections. On x86 for example, we must apply per-object
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||||
.altinstructions and .parainstructions sections when a target module loads.
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These sections must be prefixed with ".klp.arch.$objname." so that they can
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be easily identified when iterating through a patch module's Elf sections
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(See arch/x86/kernel/livepatch.c for a complete example).
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6. Symbol table and Elf section access
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5. Symbol table and Elf section access
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======================================
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A livepatch module's symbol table is accessible through module->symtab.
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@ -9936,10 +9936,12 @@ S: Maintained
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T: git git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching.git
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F: Documentation/ABI/testing/sysfs-kernel-livepatch
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F: Documentation/livepatch/
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F: arch/powerpc/include/asm/livepatch.h
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F: arch/s390/include/asm/livepatch.h
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F: arch/x86/include/asm/livepatch.h
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F: arch/x86/kernel/livepatch.c
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F: include/linux/livepatch.h
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F: kernel/livepatch/
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F: lib/livepatch/
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F: samples/livepatch/
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F: tools/testing/selftests/livepatch/
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|
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@ -276,6 +276,6 @@ static inline unsigned long __must_check clear_user(void __user *to, unsigned lo
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}
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int copy_to_user_real(void __user *dest, void *src, unsigned long count);
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void s390_kernel_write(void *dst, const void *src, size_t size);
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void *s390_kernel_write(void *dst, const void *src, size_t size);
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#endif /* __S390_UACCESS_H */
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|
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@ -19,6 +19,7 @@
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#include <linux/kasan.h>
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#include <linux/moduleloader.h>
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#include <linux/bug.h>
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#include <linux/memory.h>
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#include <asm/alternative.h>
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#include <asm/nospec-branch.h>
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#include <asm/facility.h>
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@ -174,10 +175,12 @@ int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
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}
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static int apply_rela_bits(Elf_Addr loc, Elf_Addr val,
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int sign, int bits, int shift)
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int sign, int bits, int shift,
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void *(*write)(void *dest, const void *src, size_t len))
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{
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unsigned long umax;
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long min, max;
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void *dest = (void *)loc;
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if (val & ((1UL << shift) - 1))
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return -ENOEXEC;
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@ -194,26 +197,33 @@ static int apply_rela_bits(Elf_Addr loc, Elf_Addr val,
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return -ENOEXEC;
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}
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if (bits == 8)
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*(unsigned char *) loc = val;
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else if (bits == 12)
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*(unsigned short *) loc = (val & 0xfff) |
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if (bits == 8) {
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unsigned char tmp = val;
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write(dest, &tmp, 1);
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} else if (bits == 12) {
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unsigned short tmp = (val & 0xfff) |
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(*(unsigned short *) loc & 0xf000);
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else if (bits == 16)
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*(unsigned short *) loc = val;
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else if (bits == 20)
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*(unsigned int *) loc = (val & 0xfff) << 16 |
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(val & 0xff000) >> 4 |
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(*(unsigned int *) loc & 0xf00000ff);
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else if (bits == 32)
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*(unsigned int *) loc = val;
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else if (bits == 64)
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*(unsigned long *) loc = val;
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write(dest, &tmp, 2);
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} else if (bits == 16) {
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unsigned short tmp = val;
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write(dest, &tmp, 2);
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} else if (bits == 20) {
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unsigned int tmp = (val & 0xfff) << 16 |
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(val & 0xff000) >> 4 | (*(unsigned int *) loc & 0xf00000ff);
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write(dest, &tmp, 4);
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} else if (bits == 32) {
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unsigned int tmp = val;
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write(dest, &tmp, 4);
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} else if (bits == 64) {
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unsigned long tmp = val;
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write(dest, &tmp, 8);
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}
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return 0;
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}
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static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
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const char *strtab, struct module *me)
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const char *strtab, struct module *me,
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void *(*write)(void *dest, const void *src, size_t len))
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{
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struct mod_arch_syminfo *info;
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Elf_Addr loc, val;
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@ -241,17 +251,17 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
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case R_390_64: /* Direct 64 bit. */
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val += rela->r_addend;
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if (r_type == R_390_8)
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rc = apply_rela_bits(loc, val, 0, 8, 0);
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rc = apply_rela_bits(loc, val, 0, 8, 0, write);
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else if (r_type == R_390_12)
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rc = apply_rela_bits(loc, val, 0, 12, 0);
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rc = apply_rela_bits(loc, val, 0, 12, 0, write);
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else if (r_type == R_390_16)
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rc = apply_rela_bits(loc, val, 0, 16, 0);
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rc = apply_rela_bits(loc, val, 0, 16, 0, write);
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else if (r_type == R_390_20)
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rc = apply_rela_bits(loc, val, 1, 20, 0);
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rc = apply_rela_bits(loc, val, 1, 20, 0, write);
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else if (r_type == R_390_32)
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rc = apply_rela_bits(loc, val, 0, 32, 0);
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rc = apply_rela_bits(loc, val, 0, 32, 0, write);
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else if (r_type == R_390_64)
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rc = apply_rela_bits(loc, val, 0, 64, 0);
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rc = apply_rela_bits(loc, val, 0, 64, 0, write);
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break;
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case R_390_PC16: /* PC relative 16 bit. */
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case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */
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@ -260,15 +270,15 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
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case R_390_PC64: /* PC relative 64 bit. */
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val += rela->r_addend - loc;
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if (r_type == R_390_PC16)
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rc = apply_rela_bits(loc, val, 1, 16, 0);
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rc = apply_rela_bits(loc, val, 1, 16, 0, write);
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else if (r_type == R_390_PC16DBL)
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rc = apply_rela_bits(loc, val, 1, 16, 1);
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rc = apply_rela_bits(loc, val, 1, 16, 1, write);
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else if (r_type == R_390_PC32DBL)
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rc = apply_rela_bits(loc, val, 1, 32, 1);
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rc = apply_rela_bits(loc, val, 1, 32, 1, write);
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else if (r_type == R_390_PC32)
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rc = apply_rela_bits(loc, val, 1, 32, 0);
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rc = apply_rela_bits(loc, val, 1, 32, 0, write);
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else if (r_type == R_390_PC64)
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rc = apply_rela_bits(loc, val, 1, 64, 0);
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rc = apply_rela_bits(loc, val, 1, 64, 0, write);
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break;
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case R_390_GOT12: /* 12 bit GOT offset. */
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case R_390_GOT16: /* 16 bit GOT offset. */
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@ -283,33 +293,33 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
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case R_390_GOTPLT64: /* 64 bit offset to jump slot. */
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case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */
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if (info->got_initialized == 0) {
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Elf_Addr *gotent;
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Elf_Addr *gotent = me->core_layout.base +
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me->arch.got_offset +
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info->got_offset;
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gotent = me->core_layout.base + me->arch.got_offset +
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info->got_offset;
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*gotent = val;
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write(gotent, &val, sizeof(*gotent));
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info->got_initialized = 1;
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}
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val = info->got_offset + rela->r_addend;
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if (r_type == R_390_GOT12 ||
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r_type == R_390_GOTPLT12)
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rc = apply_rela_bits(loc, val, 0, 12, 0);
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rc = apply_rela_bits(loc, val, 0, 12, 0, write);
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else if (r_type == R_390_GOT16 ||
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r_type == R_390_GOTPLT16)
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rc = apply_rela_bits(loc, val, 0, 16, 0);
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rc = apply_rela_bits(loc, val, 0, 16, 0, write);
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else if (r_type == R_390_GOT20 ||
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r_type == R_390_GOTPLT20)
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rc = apply_rela_bits(loc, val, 1, 20, 0);
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rc = apply_rela_bits(loc, val, 1, 20, 0, write);
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else if (r_type == R_390_GOT32 ||
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r_type == R_390_GOTPLT32)
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rc = apply_rela_bits(loc, val, 0, 32, 0);
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rc = apply_rela_bits(loc, val, 0, 32, 0, write);
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else if (r_type == R_390_GOT64 ||
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r_type == R_390_GOTPLT64)
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rc = apply_rela_bits(loc, val, 0, 64, 0);
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rc = apply_rela_bits(loc, val, 0, 64, 0, write);
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else if (r_type == R_390_GOTENT ||
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r_type == R_390_GOTPLTENT) {
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val += (Elf_Addr) me->core_layout.base - loc;
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rc = apply_rela_bits(loc, val, 1, 32, 1);
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rc = apply_rela_bits(loc, val, 1, 32, 1, write);
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}
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break;
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case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */
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@ -320,25 +330,29 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
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case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */
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case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */
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if (info->plt_initialized == 0) {
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unsigned int *ip;
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ip = me->core_layout.base + me->arch.plt_offset +
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info->plt_offset;
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ip[0] = 0x0d10e310; /* basr 1,0 */
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ip[1] = 0x100a0004; /* lg 1,10(1) */
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unsigned int insn[5];
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unsigned int *ip = me->core_layout.base +
|
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me->arch.plt_offset +
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info->plt_offset;
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insn[0] = 0x0d10e310; /* basr 1,0 */
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insn[1] = 0x100a0004; /* lg 1,10(1) */
|
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if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable) {
|
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unsigned int *ij;
|
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ij = me->core_layout.base +
|
||||
me->arch.plt_offset +
|
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me->arch.plt_size - PLT_ENTRY_SIZE;
|
||||
ip[2] = 0xa7f40000 + /* j __jump_r1 */
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||||
insn[2] = 0xa7f40000 + /* j __jump_r1 */
|
||||
(unsigned int)(u16)
|
||||
(((unsigned long) ij - 8 -
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(unsigned long) ip) / 2);
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} else {
|
||||
ip[2] = 0x07f10000; /* br %r1 */
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insn[2] = 0x07f10000; /* br %r1 */
|
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}
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ip[3] = (unsigned int) (val >> 32);
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ip[4] = (unsigned int) val;
|
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insn[3] = (unsigned int) (val >> 32);
|
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insn[4] = (unsigned int) val;
|
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|
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write(ip, insn, sizeof(insn));
|
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info->plt_initialized = 1;
|
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}
|
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if (r_type == R_390_PLTOFF16 ||
|
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|
|
@ -357,17 +371,17 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
|
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val += rela->r_addend - loc;
|
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}
|
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if (r_type == R_390_PLT16DBL)
|
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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)
|
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rc = apply_rela_bits(loc, val, 0, 16, 0);
|
||||
rc = apply_rela_bits(loc, val, 0, 16, 0, write);
|
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else if (r_type == R_390_PLT32DBL)
|
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rc = apply_rela_bits(loc, val, 1, 32, 1);
|
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rc = apply_rela_bits(loc, val, 1, 32, 1, write);
|
||||
else if (r_type == R_390_PLT32 ||
|
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r_type == R_390_PLTOFF32)
|
||||
rc = apply_rela_bits(loc, val, 0, 32, 0);
|
||||
rc = apply_rela_bits(loc, val, 0, 32, 0, write);
|
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else if (r_type == R_390_PLT64 ||
|
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r_type == R_390_PLTOFF64)
|
||||
rc = apply_rela_bits(loc, val, 0, 64, 0);
|
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rc = apply_rela_bits(loc, val, 0, 64, 0, write);
|
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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,
|
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val = val + rela->r_addend -
|
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((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);
|
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rc = apply_rela_bits(loc, val, 0, 16, 0, write);
|
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else if (r_type == R_390_GOTOFF32)
|
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rc = apply_rela_bits(loc, val, 0, 32, 0);
|
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rc = apply_rela_bits(loc, val, 0, 32, 0, write);
|
||||
else if (r_type == R_390_GOTOFF64)
|
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rc = apply_rela_bits(loc, val, 0, 64, 0);
|
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rc = apply_rela_bits(loc, val, 0, 64, 0, write);
|
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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. */
|
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val = (Elf_Addr) me->core_layout.base + me->arch.got_offset +
|
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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)
|
||||
|
|
|
|||
|
|
@ -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)
|
||||
|
|
|
|||
|
|
@ -362,3 +362,19 @@ void __init check_bugs(void)
|
|||
void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
|
||||
{
|
||||
}
|
||||
|
||||
void *text_poke(void *addr, const void *opcode, size_t len)
|
||||
{
|
||||
/*
|
||||
* In UML, the only reference to this function is in
|
||||
* apply_relocate_add(), which shouldn't ever actually call this
|
||||
* because UML doesn't have live patching.
|
||||
*/
|
||||
WARN_ON(1);
|
||||
|
||||
return memcpy(addr, opcode, len);
|
||||
}
|
||||
|
||||
void text_poke_sync(void)
|
||||
{
|
||||
}
|
||||
|
|
|
|||
|
|
@ -90,7 +90,6 @@ obj-$(CONFIG_X86_MPPARSE) += mpparse.o
|
|||
obj-y += apic/
|
||||
obj-$(CONFIG_X86_REBOOTFIXUPS) += reboot_fixups_32.o
|
||||
obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
|
||||
obj-$(CONFIG_LIVEPATCH) += livepatch.o
|
||||
obj-$(CONFIG_FUNCTION_TRACER) += ftrace_$(BITS).o
|
||||
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
|
||||
obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.o
|
||||
|
|
|
|||
|
|
@ -1,53 +0,0 @@
|
|||
// SPDX-License-Identifier: GPL-2.0-or-later
|
||||
/*
|
||||
* livepatch.c - x86-specific Kernel Live Patching Core
|
||||
*/
|
||||
|
||||
#include <linux/module.h>
|
||||
#include <linux/kallsyms.h>
|
||||
#include <linux/livepatch.h>
|
||||
#include <asm/text-patching.h>
|
||||
|
||||
/* Apply per-object alternatives. Based on x86 module_finalize() */
|
||||
void arch_klp_init_object_loaded(struct klp_patch *patch,
|
||||
struct klp_object *obj)
|
||||
{
|
||||
int cnt;
|
||||
struct klp_modinfo *info;
|
||||
Elf_Shdr *s, *alt = NULL, *para = NULL;
|
||||
void *aseg, *pseg;
|
||||
const char *objname;
|
||||
char sec_objname[MODULE_NAME_LEN];
|
||||
char secname[KSYM_NAME_LEN];
|
||||
|
||||
info = patch->mod->klp_info;
|
||||
objname = obj->name ? obj->name : "vmlinux";
|
||||
|
||||
/* See livepatch core code for BUILD_BUG_ON() explanation */
|
||||
BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 128);
|
||||
|
||||
for (s = info->sechdrs; s < info->sechdrs + info->hdr.e_shnum; s++) {
|
||||
/* Apply per-object .klp.arch sections */
|
||||
cnt = sscanf(info->secstrings + s->sh_name,
|
||||
".klp.arch.%55[^.].%127s",
|
||||
sec_objname, secname);
|
||||
if (cnt != 2)
|
||||
continue;
|
||||
if (strcmp(sec_objname, objname))
|
||||
continue;
|
||||
if (!strcmp(".altinstructions", secname))
|
||||
alt = s;
|
||||
if (!strcmp(".parainstructions", secname))
|
||||
para = s;
|
||||
}
|
||||
|
||||
if (alt) {
|
||||
aseg = (void *) alt->sh_addr;
|
||||
apply_alternatives(aseg, aseg + alt->sh_size);
|
||||
}
|
||||
|
||||
if (para) {
|
||||
pseg = (void *) para->sh_addr;
|
||||
apply_paravirt(pseg, pseg + para->sh_size);
|
||||
}
|
||||
}
|
||||
|
|
@ -18,6 +18,7 @@
|
|||
#include <linux/gfp.h>
|
||||
#include <linux/jump_label.h>
|
||||
#include <linux/random.h>
|
||||
#include <linux/memory.h>
|
||||
|
||||
#include <asm/text-patching.h>
|
||||
#include <asm/page.h>
|
||||
|
|
@ -126,11 +127,12 @@ int apply_relocate(Elf32_Shdr *sechdrs,
|
|||
return 0;
|
||||
}
|
||||
#else /*X86_64*/
|
||||
int apply_relocate_add(Elf64_Shdr *sechdrs,
|
||||
static int __apply_relocate_add(Elf64_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))
|
||||
{
|
||||
unsigned int i;
|
||||
Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
|
||||
|
|
@ -162,19 +164,19 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
|
|||
case R_X86_64_64:
|
||||
if (*(u64 *)loc != 0)
|
||||
goto invalid_relocation;
|
||||
*(u64 *)loc = val;
|
||||
write(loc, &val, 8);
|
||||
break;
|
||||
case R_X86_64_32:
|
||||
if (*(u32 *)loc != 0)
|
||||
goto invalid_relocation;
|
||||
*(u32 *)loc = val;
|
||||
write(loc, &val, 4);
|
||||
if (val != *(u32 *)loc)
|
||||
goto overflow;
|
||||
break;
|
||||
case R_X86_64_32S:
|
||||
if (*(s32 *)loc != 0)
|
||||
goto invalid_relocation;
|
||||
*(s32 *)loc = val;
|
||||
write(loc, &val, 4);
|
||||
if ((s64)val != *(s32 *)loc)
|
||||
goto overflow;
|
||||
break;
|
||||
|
|
@ -183,7 +185,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
|
|||
if (*(u32 *)loc != 0)
|
||||
goto invalid_relocation;
|
||||
val -= (u64)loc;
|
||||
*(u32 *)loc = val;
|
||||
write(loc, &val, 4);
|
||||
#if 0
|
||||
if ((s64)val != *(s32 *)loc)
|
||||
goto overflow;
|
||||
|
|
@ -193,7 +195,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
|
|||
if (*(u64 *)loc != 0)
|
||||
goto invalid_relocation;
|
||||
val -= (u64)loc;
|
||||
*(u64 *)loc = val;
|
||||
write(loc, &val, 8);
|
||||
break;
|
||||
default:
|
||||
pr_err("%s: Unknown rela relocation: %llu\n",
|
||||
|
|
@ -215,6 +217,33 @@ overflow:
|
|||
me->name);
|
||||
return -ENOEXEC;
|
||||
}
|
||||
|
||||
int apply_relocate_add(Elf64_Shdr *sechdrs,
|
||||
const char *strtab,
|
||||
unsigned int symindex,
|
||||
unsigned int relsec,
|
||||
struct module *me)
|
||||
{
|
||||
int ret;
|
||||
bool early = me->state == MODULE_STATE_UNFORMED;
|
||||
void *(*write)(void *, const void *, size_t) = memcpy;
|
||||
|
||||
if (!early) {
|
||||
write = text_poke;
|
||||
mutex_lock(&text_mutex);
|
||||
}
|
||||
|
||||
ret = __apply_relocate_add(sechdrs, strtab, symindex, relsec, me,
|
||||
write);
|
||||
|
||||
if (!early) {
|
||||
text_poke_sync();
|
||||
mutex_unlock(&text_mutex);
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
#endif
|
||||
|
||||
int module_finalize(const Elf_Ehdr *hdr,
|
||||
|
|
|
|||
|
|
@ -195,9 +195,6 @@ struct klp_patch {
|
|||
|
||||
int klp_enable_patch(struct klp_patch *);
|
||||
|
||||
void arch_klp_init_object_loaded(struct klp_patch *patch,
|
||||
struct klp_object *obj);
|
||||
|
||||
/* Called from the module loader during module coming/going states */
|
||||
int klp_module_coming(struct module *mod);
|
||||
void klp_module_going(struct module *mod);
|
||||
|
|
@ -234,6 +231,11 @@ void klp_shadow_free_all(unsigned long id, klp_shadow_dtor_t dtor);
|
|||
struct klp_state *klp_get_state(struct klp_patch *patch, unsigned long id);
|
||||
struct klp_state *klp_get_prev_state(unsigned long id);
|
||||
|
||||
int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs,
|
||||
const char *shstrtab, const char *strtab,
|
||||
unsigned int symindex, unsigned int secindex,
|
||||
const char *objname);
|
||||
|
||||
#else /* !CONFIG_LIVEPATCH */
|
||||
|
||||
static inline int klp_module_coming(struct module *mod) { return 0; }
|
||||
|
|
@ -242,6 +244,15 @@ static inline bool klp_patch_pending(struct task_struct *task) { return false; }
|
|||
static inline void klp_update_patch_state(struct task_struct *task) {}
|
||||
static inline void klp_copy_process(struct task_struct *child) {}
|
||||
|
||||
static inline
|
||||
int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs,
|
||||
const char *shstrtab, const char *strtab,
|
||||
unsigned int symindex, unsigned int secindex,
|
||||
const char *objname)
|
||||
{
|
||||
return 0;
|
||||
}
|
||||
|
||||
#endif /* CONFIG_LIVEPATCH */
|
||||
|
||||
#endif /* _LINUX_LIVEPATCH_H_ */
|
||||
|
|
|
|||
|
|
@ -866,14 +866,6 @@ extern int module_sysfs_initialized;
|
|||
|
||||
#define __MODULE_STRING(x) __stringify(x)
|
||||
|
||||
#ifdef CONFIG_STRICT_MODULE_RWX
|
||||
extern void module_enable_ro(const struct module *mod, bool after_init);
|
||||
extern void module_disable_ro(const struct module *mod);
|
||||
#else
|
||||
static inline void module_enable_ro(const struct module *mod, bool after_init) { }
|
||||
static inline void module_disable_ro(const struct module *mod) { }
|
||||
#endif
|
||||
|
||||
#ifdef CONFIG_GENERIC_BUG
|
||||
void module_bug_finalize(const Elf_Ehdr *, const Elf_Shdr *,
|
||||
struct module *);
|
||||
|
|
|
|||
|
|
@ -191,18 +191,21 @@ static int klp_find_object_symbol(const char *objname, const char *name,
|
|||
return -EINVAL;
|
||||
}
|
||||
|
||||
static int klp_resolve_symbols(Elf_Shdr *relasec, struct module *pmod)
|
||||
static int klp_resolve_symbols(Elf64_Shdr *sechdrs, const char *strtab,
|
||||
unsigned int symndx, Elf_Shdr *relasec,
|
||||
const char *sec_objname)
|
||||
{
|
||||
int i, cnt, vmlinux, ret;
|
||||
char objname[MODULE_NAME_LEN];
|
||||
char symname[KSYM_NAME_LEN];
|
||||
char *strtab = pmod->core_kallsyms.strtab;
|
||||
int i, cnt, ret;
|
||||
char sym_objname[MODULE_NAME_LEN];
|
||||
char sym_name[KSYM_NAME_LEN];
|
||||
Elf_Rela *relas;
|
||||
Elf_Sym *sym;
|
||||
unsigned long sympos, addr;
|
||||
bool sym_vmlinux;
|
||||
bool sec_vmlinux = !strcmp(sec_objname, "vmlinux");
|
||||
|
||||
/*
|
||||
* Since the field widths for objname and symname in the sscanf()
|
||||
* Since the field widths for sym_objname and sym_name in the sscanf()
|
||||
* call are hard-coded and correspond to MODULE_NAME_LEN and
|
||||
* KSYM_NAME_LEN respectively, we must make sure that MODULE_NAME_LEN
|
||||
* and KSYM_NAME_LEN have the values we expect them to have.
|
||||
|
|
@ -216,27 +219,40 @@ static int klp_resolve_symbols(Elf_Shdr *relasec, struct module *pmod)
|
|||
relas = (Elf_Rela *) relasec->sh_addr;
|
||||
/* For each rela in this klp relocation section */
|
||||
for (i = 0; i < relasec->sh_size / sizeof(Elf_Rela); i++) {
|
||||
sym = pmod->core_kallsyms.symtab + ELF_R_SYM(relas[i].r_info);
|
||||
sym = (Elf64_Sym *)sechdrs[symndx].sh_addr + ELF_R_SYM(relas[i].r_info);
|
||||
if (sym->st_shndx != SHN_LIVEPATCH) {
|
||||
pr_err("symbol %s is not marked as a livepatch symbol\n",
|
||||
strtab + sym->st_name);
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
/* Format: .klp.sym.objname.symname,sympos */
|
||||
/* Format: .klp.sym.sym_objname.sym_name,sympos */
|
||||
cnt = sscanf(strtab + sym->st_name,
|
||||
".klp.sym.%55[^.].%127[^,],%lu",
|
||||
objname, symname, &sympos);
|
||||
sym_objname, sym_name, &sympos);
|
||||
if (cnt != 3) {
|
||||
pr_err("symbol %s has an incorrectly formatted name\n",
|
||||
strtab + sym->st_name);
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
sym_vmlinux = !strcmp(sym_objname, "vmlinux");
|
||||
|
||||
/*
|
||||
* Prevent module-specific KLP rela sections from referencing
|
||||
* vmlinux symbols. This helps prevent ordering issues with
|
||||
* module special section initializations. Presumably such
|
||||
* symbols are exported and normal relas can be used instead.
|
||||
*/
|
||||
if (!sec_vmlinux && sym_vmlinux) {
|
||||
pr_err("invalid access to vmlinux symbol '%s' from module-specific livepatch relocation section",
|
||||
sym_name);
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
/* klp_find_object_symbol() treats a NULL objname as vmlinux */
|
||||
vmlinux = !strcmp(objname, "vmlinux");
|
||||
ret = klp_find_object_symbol(vmlinux ? NULL : objname,
|
||||
symname, sympos, &addr);
|
||||
ret = klp_find_object_symbol(sym_vmlinux ? NULL : sym_objname,
|
||||
sym_name, sympos, &addr);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
|
|
@ -246,54 +262,59 @@ static int klp_resolve_symbols(Elf_Shdr *relasec, struct module *pmod)
|
|||
return 0;
|
||||
}
|
||||
|
||||
static int klp_write_object_relocations(struct module *pmod,
|
||||
struct klp_object *obj)
|
||||
/*
|
||||
* At a high-level, there are two types of klp relocation sections: those which
|
||||
* reference symbols which live in vmlinux; and those which reference symbols
|
||||
* which live in other modules. This function is called for both types:
|
||||
*
|
||||
* 1) When a klp module itself loads, the module code calls this function to
|
||||
* write vmlinux-specific klp relocations (.klp.rela.vmlinux.* sections).
|
||||
* These relocations are written to the klp module text to allow the patched
|
||||
* code/data to reference unexported vmlinux symbols. They're written as
|
||||
* early as possible to ensure that other module init code (.e.g.,
|
||||
* jump_label_apply_nops) can access any unexported vmlinux symbols which
|
||||
* might be referenced by the klp module's special sections.
|
||||
*
|
||||
* 2) When a to-be-patched module loads -- or is already loaded when a
|
||||
* corresponding klp module loads -- klp code calls this function to write
|
||||
* module-specific klp relocations (.klp.rela.{module}.* sections). These
|
||||
* are written to the klp module text to allow the patched code/data to
|
||||
* reference symbols which live in the to-be-patched module or one of its
|
||||
* module dependencies. Exported symbols are supported, in addition to
|
||||
* unexported symbols, in order to enable late module patching, which allows
|
||||
* the to-be-patched module to be loaded and patched sometime *after* the
|
||||
* klp module is loaded.
|
||||
*/
|
||||
int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs,
|
||||
const char *shstrtab, const char *strtab,
|
||||
unsigned int symndx, unsigned int secndx,
|
||||
const char *objname)
|
||||
{
|
||||
int i, cnt, ret = 0;
|
||||
const char *objname, *secname;
|
||||
int cnt, ret;
|
||||
char sec_objname[MODULE_NAME_LEN];
|
||||
Elf_Shdr *sec;
|
||||
Elf_Shdr *sec = sechdrs + secndx;
|
||||
|
||||
if (WARN_ON(!klp_is_object_loaded(obj)))
|
||||
/*
|
||||
* Format: .klp.rela.sec_objname.section_name
|
||||
* See comment in klp_resolve_symbols() for an explanation
|
||||
* of the selected field width value.
|
||||
*/
|
||||
cnt = sscanf(shstrtab + sec->sh_name, ".klp.rela.%55[^.]",
|
||||
sec_objname);
|
||||
if (cnt != 1) {
|
||||
pr_err("section %s has an incorrectly formatted name\n",
|
||||
shstrtab + sec->sh_name);
|
||||
return -EINVAL;
|
||||
|
||||
objname = klp_is_module(obj) ? obj->name : "vmlinux";
|
||||
|
||||
/* For each klp relocation section */
|
||||
for (i = 1; i < pmod->klp_info->hdr.e_shnum; i++) {
|
||||
sec = pmod->klp_info->sechdrs + i;
|
||||
secname = pmod->klp_info->secstrings + sec->sh_name;
|
||||
if (!(sec->sh_flags & SHF_RELA_LIVEPATCH))
|
||||
continue;
|
||||
|
||||
/*
|
||||
* Format: .klp.rela.sec_objname.section_name
|
||||
* See comment in klp_resolve_symbols() for an explanation
|
||||
* of the selected field width value.
|
||||
*/
|
||||
cnt = sscanf(secname, ".klp.rela.%55[^.]", sec_objname);
|
||||
if (cnt != 1) {
|
||||
pr_err("section %s has an incorrectly formatted name\n",
|
||||
secname);
|
||||
ret = -EINVAL;
|
||||
break;
|
||||
}
|
||||
|
||||
if (strcmp(objname, sec_objname))
|
||||
continue;
|
||||
|
||||
ret = klp_resolve_symbols(sec, pmod);
|
||||
if (ret)
|
||||
break;
|
||||
|
||||
ret = apply_relocate_add(pmod->klp_info->sechdrs,
|
||||
pmod->core_kallsyms.strtab,
|
||||
pmod->klp_info->symndx, i, pmod);
|
||||
if (ret)
|
||||
break;
|
||||
}
|
||||
|
||||
return ret;
|
||||
if (strcmp(objname ? objname : "vmlinux", sec_objname))
|
||||
return 0;
|
||||
|
||||
ret = klp_resolve_symbols(sechdrs, strtab, symndx, sec, sec_objname);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
return apply_relocate_add(sechdrs, strtab, symndx, secndx, pmod);
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -724,10 +745,27 @@ static int klp_init_func(struct klp_object *obj, struct klp_func *func)
|
|||
func->old_sympos ? func->old_sympos : 1);
|
||||
}
|
||||
|
||||
/* Arches may override this to finish any remaining arch-specific tasks */
|
||||
void __weak arch_klp_init_object_loaded(struct klp_patch *patch,
|
||||
struct klp_object *obj)
|
||||
static int klp_apply_object_relocs(struct klp_patch *patch,
|
||||
struct klp_object *obj)
|
||||
{
|
||||
int i, ret;
|
||||
struct klp_modinfo *info = patch->mod->klp_info;
|
||||
|
||||
for (i = 1; i < info->hdr.e_shnum; i++) {
|
||||
Elf_Shdr *sec = info->sechdrs + i;
|
||||
|
||||
if (!(sec->sh_flags & SHF_RELA_LIVEPATCH))
|
||||
continue;
|
||||
|
||||
ret = klp_apply_section_relocs(patch->mod, info->sechdrs,
|
||||
info->secstrings,
|
||||
patch->mod->core_kallsyms.strtab,
|
||||
info->symndx, i, obj->name);
|
||||
if (ret)
|
||||
return ret;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* parts of the initialization that is done only when the object is loaded */
|
||||
|
|
@ -737,21 +775,18 @@ static int klp_init_object_loaded(struct klp_patch *patch,
|
|||
struct klp_func *func;
|
||||
int ret;
|
||||
|
||||
mutex_lock(&text_mutex);
|
||||
|
||||
module_disable_ro(patch->mod);
|
||||
ret = klp_write_object_relocations(patch->mod, obj);
|
||||
if (ret) {
|
||||
module_enable_ro(patch->mod, true);
|
||||
mutex_unlock(&text_mutex);
|
||||
return ret;
|
||||
if (klp_is_module(obj)) {
|
||||
/*
|
||||
* Only write module-specific relocations here
|
||||
* (.klp.rela.{module}.*). vmlinux-specific relocations were
|
||||
* written earlier during the initialization of the klp module
|
||||
* itself.
|
||||
*/
|
||||
ret = klp_apply_object_relocs(patch, obj);
|
||||
if (ret)
|
||||
return ret;
|
||||
}
|
||||
|
||||
arch_klp_init_object_loaded(patch, obj);
|
||||
module_enable_ro(patch->mod, true);
|
||||
|
||||
mutex_unlock(&text_mutex);
|
||||
|
||||
klp_for_each_func(obj, func) {
|
||||
ret = klp_find_object_symbol(obj->name, func->old_name,
|
||||
func->old_sympos,
|
||||
|
|
@ -1139,6 +1174,11 @@ int klp_module_coming(struct module *mod)
|
|||
if (WARN_ON(mod->state != MODULE_STATE_COMING))
|
||||
return -EINVAL;
|
||||
|
||||
if (!strcmp(mod->name, "vmlinux")) {
|
||||
pr_err("vmlinux.ko: invalid module name");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
mutex_lock(&klp_mutex);
|
||||
/*
|
||||
* Each module has to know that klp_module_coming()
|
||||
|
|
|
|||
|
|
@ -2000,20 +2000,7 @@ static void frob_writable_data(const struct module_layout *layout,
|
|||
(layout->size - layout->ro_after_init_size) >> PAGE_SHIFT);
|
||||
}
|
||||
|
||||
/* livepatching wants to disable read-only so it can frob module. */
|
||||
void module_disable_ro(const struct module *mod)
|
||||
{
|
||||
if (!rodata_enabled)
|
||||
return;
|
||||
|
||||
frob_text(&mod->core_layout, set_memory_rw);
|
||||
frob_rodata(&mod->core_layout, set_memory_rw);
|
||||
frob_ro_after_init(&mod->core_layout, set_memory_rw);
|
||||
frob_text(&mod->init_layout, set_memory_rw);
|
||||
frob_rodata(&mod->init_layout, set_memory_rw);
|
||||
}
|
||||
|
||||
void module_enable_ro(const struct module *mod, bool after_init)
|
||||
static void module_enable_ro(const struct module *mod, bool after_init)
|
||||
{
|
||||
if (!rodata_enabled)
|
||||
return;
|
||||
|
|
@ -2041,6 +2028,7 @@ static void module_enable_nx(const struct module *mod)
|
|||
|
||||
#else /* !CONFIG_STRICT_MODULE_RWX */
|
||||
static void module_enable_nx(const struct module *mod) { }
|
||||
static void module_enable_ro(const struct module *mod, bool after_init) {}
|
||||
#endif /* CONFIG_STRICT_MODULE_RWX */
|
||||
static void module_enable_x(const struct module *mod)
|
||||
{
|
||||
|
|
@ -2337,11 +2325,13 @@ static int apply_relocations(struct module *mod, const struct load_info *info)
|
|||
if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC))
|
||||
continue;
|
||||
|
||||
/* Livepatch relocation sections are applied by livepatch */
|
||||
if (info->sechdrs[i].sh_flags & SHF_RELA_LIVEPATCH)
|
||||
continue;
|
||||
|
||||
if (info->sechdrs[i].sh_type == SHT_REL)
|
||||
err = klp_apply_section_relocs(mod, info->sechdrs,
|
||||
info->secstrings,
|
||||
info->strtab,
|
||||
info->index.sym, i,
|
||||
NULL);
|
||||
else if (info->sechdrs[i].sh_type == SHT_REL)
|
||||
err = apply_relocate(info->sechdrs, info->strtab,
|
||||
info->index.sym, i, mod);
|
||||
else if (info->sechdrs[i].sh_type == SHT_RELA)
|
||||
|
|
|
|||
Loading…
Reference in a new issue