mirror of https://gitee.com/openkylin/linux.git
s390/module: Use s390_kernel_write() for late relocations
Because of late module patching, a livepatch module needs to be able to
apply some of its relocations well after it has been loaded. Instead of
playing games with module_{dis,en}able_ro(), use existing text poking
mechanisms to apply relocations after module loading.
So far only x86, s390 and Power have HAVE_LIVEPATCH but only the first
two also have STRICT_MODULE_RWX.
This will allow removal of the last module_disable_ro() usage in
livepatch. The ultimate goal is to completely disallow making
executable mappings writable.
[ jpoimboe: Split up patches. Use mod state to determine whether
memcpy() can be used. Test and add fixes. ]
Cc: linux-s390@vger.kernel.org
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> # s390
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Peter Zijlstra
Jiri Kosina
parent
cb2cceaefb
commit
be2422612a
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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 +
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me->arch.plt_offset +
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me->arch.plt_size - PLT_ENTRY_SIZE;
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ip[2] = 0xa7f40000 + /* j __jump_r1 */
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insn[2] = 0xa7f40000 + /* j __jump_r1 */
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(unsigned int)(u16)
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(((unsigned long) ij - 8 -
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(unsigned long) ip) / 2);
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} else {
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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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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);
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rc = apply_rela_bits(loc, val, 1, 16, 1, write);
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else if (r_type == R_390_PLTOFF16)
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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_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);
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else if (r_type == R_390_PLT32 ||
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r_type == R_390_PLTOFF32)
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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_PLT64 ||
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r_type == R_390_PLTOFF64)
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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_GOTOFF16: /* 16 bit offset to GOT. */
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case R_390_GOTOFF32: /* 32 bit offset to GOT. */
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@ -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);
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if (r_type == R_390_GOTOFF16)
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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_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);
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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;
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case R_390_GOTPC: /* 32 bit PC relative offset to GOT. */
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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;
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if (r_type == R_390_GOTPC)
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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_GOTPCDBL)
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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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break;
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case R_390_COPY:
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case R_390_GLOB_DAT: /* Create GOT entry. */
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@ -412,9 +426,10 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
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return 0;
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}
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int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
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static int __apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
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unsigned int symindex, unsigned int relsec,
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struct module *me)
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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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Elf_Addr base;
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Elf_Sym *symtab;
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@ -430,13 +445,27 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
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n = sechdrs[relsec].sh_size / sizeof(Elf_Rela);
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for (i = 0; i < n; i++, rela++) {
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rc = apply_rela(rela, base, symtab, strtab, me);
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rc = apply_rela(rela, base, symtab, strtab, me, write);
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if (rc)
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return rc;
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}
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return 0;
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}
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int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
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unsigned int symindex, unsigned int relsec,
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struct module *me)
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{
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bool early = me->state == MODULE_STATE_UNFORMED;
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void *(*write)(void *, const void *, size_t) = memcpy;
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if (!early)
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write = s390_kernel_write;
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return __apply_relocate_add(sechdrs, strtab, symindex, relsec, me,
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write);
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}
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int module_finalize(const Elf_Ehdr *hdr,
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const Elf_Shdr *sechdrs,
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struct module *me)
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