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Message-ID: <e8f2de6d-b535-aea9-0eeb-465f172284d5@yahoo.com>
Date: Wed, 20 Mar 2019 21:33:11 -0400
From: Ruslan Nikolaev <nruslan_devel@...oo.com>
To: kernel-hardening@...ts.openwall.com
Cc: thgarnie@...gle.com, x86@...nel.org, kstewart@...uxfoundation.org,
gregkh@...uxfoundation.org, keescook@...omium.org, jpoimboe@...hat.com
Subject: [PATCH v2 02/02]: Support for PIC modules
The patchset extends the prior PIE kernel patch (by Thomas Garnier) to also
support position-independent modules that can be placed anywhere in the
48/64-bit address space (for better KASLR). The patch extends PIE v6.
The second part implements support for position-independent modules.
Signed-off-by: Ruslan Nikolaev <rnikola@...edu>
Signed-off-by: Hassan Nadeem <hnadeem@...edu>
---
Makefile | 8
arch/x86/Kconfig | 12 +
arch/x86/Makefile | 11 +
arch/x86/include/asm/alternative.h | 6
arch/x86/include/asm/arch_hweight.h | 5
arch/x86/include/asm/elf.h | 3
arch/x86/include/asm/jump_label.h | 4
arch/x86/include/asm/kvm_host.h | 15 +
arch/x86/include/asm/module.h | 26 ++-
arch/x86/include/asm/paravirt.h | 2
arch/x86/include/asm/paravirt_types.h | 9 -
arch/x86/include/asm/percpu.h | 8
arch/x86/include/asm/uaccess.h | 60 ++++++-
arch/x86/include/asm/xen/hypercall.h | 20 ++
arch/x86/kernel/Makefile | 3
arch/x86/kernel/alternative.c | 24 ++
arch/x86/kernel/ftrace.c | 14 -
arch/x86/kernel/module-plt-stub.S | 23 ++
arch/x86/kernel/module.c | 286
++++++++++++++++++++++++++++++----
arch/x86/kernel/module.lds | 1
arch/x86/kvm/emulate.c | 1
arch/x86/kvm/vmx/vmenter.S | 15 +
arch/x86/module-lib/Makefile | 3
arch/x86/module-lib/retpoline.S | 47 +++++
arch/x86/tools/relocs.c | 4
arch/x86/xen/xen-head.S | 2
scripts/Makefile.modpost | 2
scripts/recordmcount.c | 3
tools/objtool/check.c | 40 +++-
29 files changed, 570 insertions(+), 87 deletions(-)
diff -uprN a/arch/x86/include/asm/alternative.h
b/arch/x86/include/asm/alternative.h
--- a/arch/x86/include/asm/alternative.h 2019-03-16 10:50:57.097692208 -0400
+++ b/arch/x86/include/asm/alternative.h 2019-03-20 19:42:23.631815425 -0400
@@ -207,7 +207,7 @@ static inline int alternatives_text_rese
/* Like alternative_io, but for replacing a direct call with another
one. */
#define alternative_call(oldfunc, newfunc, feature, output, input...) \
- asm volatile (ALTERNATIVE("call %P[old]", "call %P[new]", feature) \
+ asm volatile (ALTERNATIVE(_ASM_CALL(%p[old]), _ASM_CALL(%p[new]),
feature) \
: output : [old] "X" (oldfunc), [new] "X" (newfunc), ## input)
/*
@@ -218,8 +218,8 @@ static inline int alternatives_text_rese
*/
#define alternative_call_2(oldfunc, newfunc1, feature1, newfunc2,
feature2, \
output, input...) \
- asm volatile (ALTERNATIVE_2("call %P[old]", "call %P[new1]", feature1,\
- "call %P[new2]", feature2) \
+ asm volatile (ALTERNATIVE_2(_ASM_CALL(%p[old]), _ASM_CALL(%p[new1]),
feature1,\
+ _ASM_CALL(%p[new2]), feature2) \
: output, ASM_CALL_CONSTRAINT \
: [old] "X" (oldfunc), [new1] "X" (newfunc1), \
[new2] "X" (newfunc2), ## input)
diff -uprN a/arch/x86/include/asm/arch_hweight.h
b/arch/x86/include/asm/arch_hweight.h
--- a/arch/x86/include/asm/arch_hweight.h 2019-03-13 17:01:32.000000000
-0400
+++ b/arch/x86/include/asm/arch_hweight.h 2019-03-20 19:42:23.631815425
-0400
@@ -3,6 +3,7 @@
#define _ASM_X86_HWEIGHT_H
#include <asm/cpufeatures.h>
+#include <asm/asm.h>
#ifdef CONFIG_64BIT
#define REG_IN "D"
@@ -18,7 +19,7 @@ static __always_inline unsigned int __ar
{
unsigned int res;
- asm (ALTERNATIVE("call __sw_hweight32", "popcntl %1, %0",
X86_FEATURE_POPCNT)
+ asm (ALTERNATIVE(_ASM_CALL(__sw_hweight32), "popcntl %1, %0",
X86_FEATURE_POPCNT)
: "="REG_OUT (res)
: REG_IN (w));
@@ -46,7 +47,7 @@ static __always_inline unsigned long __a
{
unsigned long res;
- asm (ALTERNATIVE("call __sw_hweight64", "popcntq %1, %0",
X86_FEATURE_POPCNT)
+ asm (ALTERNATIVE(_ASM_CALL(__sw_hweight64), "popcntq %1, %0",
X86_FEATURE_POPCNT)
: "="REG_OUT (res)
: REG_IN (w));
diff -uprN a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
--- a/arch/x86/include/asm/elf.h 2019-03-13 17:01:32.000000000 -0400
+++ b/arch/x86/include/asm/elf.h 2019-03-20 19:42:23.631815425 -0400
@@ -65,6 +65,9 @@ typedef struct user_fxsr_struct elf_fpxr
#define R_X86_64_PC8 15 /* 8 bit sign extended pc relative */
#define R_X86_64_PC64 24 /* Place relative 64-bit signed */
+#define R_X86_64_GOTPCRELX 41 /* Relaxed R_X86_64_GOTPCREL */
+#define R_X86_64_REX_GOTPCRELX 42 /* ... with the REX prefix */
+
/*
* These are used to set parameters in the core dumps.
*/
diff -uprN a/arch/x86/include/asm/jump_label.h
b/arch/x86/include/asm/jump_label.h
--- a/arch/x86/include/asm/jump_label.h 2019-03-16 10:50:57.097692208 -0400
+++ b/arch/x86/include/asm/jump_label.h 2019-03-20 19:42:23.631815425 -0400
@@ -25,7 +25,7 @@ static __always_inline bool arch_static_
".pushsection __jump_table, \"aw\" \n\t"
_ASM_ALIGN "\n\t"
".long 1b - ., %l[l_yes] - . \n\t"
- _ASM_PTR "%P0 - .\n\t"
+ _ASM_PTR "%p0 - .\n\t"
".popsection \n\t"
: : "X" (&((char *)key)[branch]) : : l_yes);
@@ -42,7 +42,7 @@ static __always_inline bool arch_static_
".pushsection __jump_table, \"aw\" \n\t"
_ASM_ALIGN "\n\t"
".long 1b - ., %l[l_yes] - . \n\t"
- _ASM_PTR "%P0 - .\n\t"
+ _ASM_PTR "%p0 - .\n\t"
".popsection \n\t"
: : "X" (&((char *)key)[branch]) : : l_yes);
diff -uprN a/arch/x86/include/asm/kvm_host.h
b/arch/x86/include/asm/kvm_host.h
--- a/arch/x86/include/asm/kvm_host.h 2019-03-16 10:50:57.101692298 -0400
+++ b/arch/x86/include/asm/kvm_host.h 2019-03-20 19:42:23.631815425 -0400
@@ -1494,20 +1494,31 @@ enum {
*/
asmlinkage void kvm_spurious_fault(void);
+#if defined(MODULE) && defined(CONFIG_X86_PIC)
+# define ____kvm_check_rebooting \
+ "pushq %%rax \n\t" \
+ "movq kvm_rebooting@...PCREL(%%rip), %%rax \n\t" \
+ "cmpb $0, (%%rax) \n\t" \
+ "popq %%rax \n\t"
+#else
+# define ____kvm_check_rebooting \
+ "cmpb $0, kvm_rebooting" __ASM_SEL(,(%%rip)) " \n\t"
+#endif
+
#define ____kvm_handle_fault_on_reboot(insn, cleanup_insn) \
"666: " insn "\n\t" \
"668: \n\t" \
".pushsection .fixup, \"ax\" \n" \
"667: \n\t" \
cleanup_insn "\n\t" \
- "cmpb $0, kvm_rebooting" __ASM_SEL(, (%%rip)) " \n\t" \
+ ____kvm_check_rebooting \
"jne 668b \n\t" \
__ASM_SIZE(push) "$0 \n\t" \
__ASM_SIZE(push) "%%" _ASM_AX " \n\t" \
_ASM_MOVABS " $666b, %%" _ASM_AX "\n\t" \
_ASM_MOV " %%" _ASM_AX ", " __ASM_SEL(4, 8) "(%%" _ASM_SP ") \n\t" \
__ASM_SIZE(pop) "%%" _ASM_AX " \n\t" \
- "jmp kvm_spurious_fault \n\t" \
+ _ASM_JMP(kvm_spurious_fault) " \n\t" \
".popsection \n\t" \
_ASM_EXTABLE(666b, 667b)
diff -uprN a/arch/x86/include/asm/module.h b/arch/x86/include/asm/module.h
--- a/arch/x86/include/asm/module.h 2019-03-16 10:50:57.105692388 -0400
+++ b/arch/x86/include/asm/module.h 2019-03-20 19:42:23.631815425 -0400
@@ -5,13 +5,32 @@
#include <asm-generic/module.h>
#include <asm/orc_types.h>
-#ifdef CONFIG_X86_PIE
+extern const char __THUNK_FOR_PLT[];
+extern const unsigned int __THUNK_FOR_PLT_SIZE;
+
+#define PLT_ENTRY_ALIGNMENT 16
+struct plt_entry {
+#ifdef CONFIG_RETPOLINE
+ u8 mov_ins[3];
+ u32 rel_addr;
+ u8 thunk[0];
+#else
+ u16 jmp_ins;
+ u32 rel_addr;
+#endif
+} __packed __aligned(PLT_ENTRY_ALIGNMENT);
+
struct mod_got_sec {
struct elf64_shdr *got;
int got_num_entries;
int got_max_entries;
};
-#endif
+
+struct mod_plt_sec {
+ struct elf64_shdr *plt;
+ int plt_num_entries;
+ int plt_max_entries;
+};
struct mod_arch_specific {
#ifdef CONFIG_UNWINDER_ORC
@@ -19,9 +38,8 @@ struct mod_arch_specific {
int *orc_unwind_ip;
struct orc_entry *orc_unwind;
#endif
-#ifdef CONFIG_X86_PIE
struct mod_got_sec core;
-#endif
+ struct mod_plt_sec core_plt;
};
#ifdef CONFIG_X86_64
diff -uprN a/arch/x86/include/asm/paravirt.h
b/arch/x86/include/asm/paravirt.h
--- a/arch/x86/include/asm/paravirt.h 2019-03-13 17:01:32.000000000 -0400
+++ b/arch/x86/include/asm/paravirt.h 2019-03-20 19:42:23.631815425 -0400
@@ -741,7 +741,7 @@ bool __raw_callee_save___native_vcpu_is_
PV_THUNK_NAME(func) ":" \
FRAME_BEGIN \
PV_SAVE_ALL_CALLER_REGS \
- "call " #func ";" \
+ _ASM_CALL(func) ";" \
PV_RESTORE_ALL_CALLER_REGS \
FRAME_END \
"ret;" \
diff -uprN a/arch/x86/include/asm/paravirt_types.h
b/arch/x86/include/asm/paravirt_types.h
--- a/arch/x86/include/asm/paravirt_types.h 2019-03-16
10:50:57.097692208 -0400
+++ b/arch/x86/include/asm/paravirt_types.h 2019-03-20
19:42:23.631815425 -0400
@@ -342,7 +342,7 @@ extern struct paravirt_patch_template pv
#define PARAVIRT_PATCH(x) \
(offsetof(struct paravirt_patch_template, x) / sizeof(void *))
-#ifdef CONFIG_X86_PIE
+#if defined(CONFIG_X86_PIE) || (defined(MODULE) && defined(CONFIG_X86_PIC))
#define paravirt_opptr_call "a"
#define paravirt_opptr_type "p"
#else
@@ -360,7 +360,11 @@ extern struct paravirt_patch_template pv
* Generate some code, and mark it as patchable by the
* apply_paravirt() alternate instruction patcher.
*/
-#define _paravirt_alt(insn_string, type, clobber) \
+#if defined(MODULE) && defined(CONFIG_X86_PIC)
+# define _paravirt_alt(insn_string, type, clobber) \
+ insn_string "\n"
+#else
+# define _paravirt_alt(insn_string, type, clobber) \
"771:\n\t" insn_string "\n" "772:\n" \
".pushsection .parainstructions,\"a\"\n" \
_ASM_ALIGN "\n" \
@@ -369,6 +373,7 @@ extern struct paravirt_patch_template pv
" .byte 772b-771b\n" \
" .short " clobber "\n" \
".popsection\n"
+#endif
/* Generate patchable code, with the default asm parameters. */
#define paravirt_alt(insn_string) \
diff -uprN a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
--- a/arch/x86/include/asm/percpu.h 2019-03-16 10:50:57.097692208 -0400
+++ b/arch/x86/include/asm/percpu.h 2019-03-20 19:42:23.631815425 -0400
@@ -216,7 +216,7 @@ do { \
})
/* Position Independent code uses relative addresses only */
-#ifdef CONFIG_X86_PIE
+#if defined(CONFIG_X86_PIE) || (defined(MODULE) && defined(CONFIG_X86_PIC))
#define __percpu_stable_arg __percpu_arg(a1)
#else
#define __percpu_stable_arg __percpu_arg(P1)
@@ -502,6 +502,12 @@ do { \
* is not supported on early AMD64 processors so we must be able to
emulate
* it in software. The address used in the cmpxchg16 instruction must be
* aligned to a 16 byte boundary.
+ *
+ * ATTN: For PIC modules, it will not work due to the direct call.
+ * Technically, _ASM_CALL should be used here instead of 'call'. However,
+ * this will not work properly when RETPOLINE is enabled because %rax is
+ * clobbered. Luckily, this macro seems to be only used by mm/slub.c so
+ * far which cannot be compiled as a module.
*/
#define percpu_cmpxchg16b_double(pcp1, pcp2, o1, o2, n1, n2) \
({ \
diff -uprN a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
--- a/arch/x86/include/asm/uaccess.h 2019-03-13 17:01:32.000000000 -0400
+++ b/arch/x86/include/asm/uaccess.h 2019-03-20 19:42:23.631815425 -0400
@@ -11,6 +11,7 @@
#include <asm/page.h>
#include <asm/smap.h>
#include <asm/extable.h>
+#include <asm/nospec-branch.h>
/*
* The fs value determines whether argument validity checking should be
@@ -165,13 +166,55 @@ __typeof__(__builtin_choose_expr(sizeof(
* Clang/LLVM cares about the size of the register, but still wants
* the base register for something that ends up being a pair.
*/
+#if defined(CONFIG_RETPOLINE) && defined(MODULE) && defined(CONFIG_X86_PIC)
+/*
+ * Handle specially for PIC modules when RETPOLINE is enabled
+ * to avoid %rax from being clobbered by the corresponding PLT stub.
+ */
+#define get_user(x, ptr) \
+({ \
+ void *__target; \
+ int __ret_gu; \
+ register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \
+ __chk_user_ptr(ptr); \
+ might_fault(); \
+ switch (sizeof(*(ptr))) { \
+ case 1: \
+ __target = &__get_user_1; \
+ break; \
+ case 2: \
+ __target = &__get_user_2; \
+ break; \
+ case 4: \
+ __target = &__get_user_4; \
+ break; \
+ case 8: \
+ __target = &__get_user_8; \
+ break; \
+ default: \
+ __target = &__get_user_bad; \
+ break; \
+ } \
+ asm volatile(CALL_NOSPEC \
+ : "=a" (__ret_gu), "=r" (__val_gu), \
+ ASM_CALL_CONSTRAINT \
+ : "0" (ptr), [thunk_target] "r" (__target)); \
+ (x) = (__force __typeof__(*(ptr))) __val_gu; \
+ __builtin_expect(__ret_gu, 0); \
+})
+
+#define __put_user_x(size, x, ptr, __ret_pu) \
+ asm volatile(CALL_NOSPEC : "=a" (__ret_pu) \
+ : "0" ((typeof(*(ptr)))(x)), "c" (ptr), \
+ [thunk_target] "r" (&__put_user_##size) : "ebx")
+#else
#define get_user(x, ptr) \
({ \
int __ret_gu; \
register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \
__chk_user_ptr(ptr); \
might_fault(); \
- asm volatile("call __get_user_%P4" \
+ asm volatile(_ASM_CALL(__get_user_%P4) \
: "=a" (__ret_gu), "=r" (__val_gu), \
ASM_CALL_CONSTRAINT \
: "0" (ptr), "i" (sizeof(*(ptr)))); \
@@ -180,9 +223,9 @@ __typeof__(__builtin_choose_expr(sizeof(
})
#define __put_user_x(size, x, ptr, __ret_pu) \
- asm volatile("call __put_user_" #size : "=a" (__ret_pu) \
+ asm volatile(_ASM_CALL(__put_user_##size) : "=a" (__ret_pu) \
: "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
-
+#endif
#ifdef CONFIG_X86_32
@@ -204,9 +247,16 @@ __typeof__(__builtin_choose_expr(sizeof(
_ASM_EXTABLE_EX(2b, 3b) \
: : "A" (x), "r" (addr))
+#if defined(CONFIG_RETPOLINE) && defined(MODULE) && defined(CONFIG_X86_PIC)
#define __put_user_x8(x, ptr, __ret_pu) \
- asm volatile("call __put_user_8" : "=a" (__ret_pu) \
+ asm volatile(CALL_NOSPEC : "=a" (__ret_pu) \
+ : "A" ((typeof(*(ptr)))(x)), "c" (ptr), \
+ [thunk_target] "r" (&__put_user_8) : "ebx")
+#else
+#define __put_user_x8(x, ptr, __ret_pu) \
+ asm volatile(_ASM_CALL(__put_user_8) : "=a" (__ret_pu) \
: "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
+#endif
#else
#define __put_user_goto_u64(x, ptr, label) \
__put_user_goto(x, ptr, "q", "", "er", label)
@@ -264,7 +314,7 @@ extern void __put_user_8(void);
__put_user_x8(__pu_val, ptr, __ret_pu); \
break; \
default: \
- __put_user_x(X, __pu_val, ptr, __ret_pu); \
+ __put_user_x(bad, __pu_val, ptr, __ret_pu); \
break; \
} \
__builtin_expect(__ret_pu, 0); \
diff -uprN a/arch/x86/include/asm/xen/hypercall.h
b/arch/x86/include/asm/xen/hypercall.h
--- a/arch/x86/include/asm/xen/hypercall.h 2019-03-13 17:01:32.000000000
-0400
+++ b/arch/x86/include/asm/xen/hypercall.h 2019-03-20 19:42:23.631815425
-0400
@@ -88,9 +88,25 @@ struct xen_dm_op_buf;
extern struct { char _entry[32]; } hypercall_page[];
-#define __HYPERCALL "call hypercall_page+%c[offset]"
-#define __HYPERCALL_ENTRY(x) \
+#if defined(MODULE) && defined(CONFIG_X86_PIC)
+# define HYPERCALL(x) long xen_hypercall_##x(void);
+# include <asm/xen-hypercalls.h>
+# undef HYPERCALL
+# ifdef CONFIG_RETPOLINE
+# include <asm/nospec-branch.h>
+# define __HYPERCALL CALL_NOSPEC
+# define __HYPERCALL_ENTRY(x) \
+ [thunk_target] "a" (xen_hypercall_##x)
+# else
+# define __HYPERCALL "call *%p[name]@GOTPCREL(%%rip)"
+# define __HYPERCALL_ENTRY(x) \
+ [name] "X" (xen_hypercall_##x)
+# endif
+#else
+# define __HYPERCALL "call hypercall_page+%c[offset]"
+# define __HYPERCALL_ENTRY(x) \
[offset] "i" (__HYPERVISOR_##x * sizeof(hypercall_page[0]))
+#endif
#ifdef CONFIG_X86_32
#define __HYPERCALL_RETREG "eax"
diff -uprN a/arch/x86/Kconfig b/arch/x86/Kconfig
--- a/arch/x86/Kconfig 2019-03-16 10:50:57.109692478 -0400
+++ b/arch/x86/Kconfig 2019-03-20 19:42:23.631815425 -0400
@@ -2244,9 +2244,19 @@ config X86_PIE
select DYNAMIC_MODULE_BASE
select MODULE_REL_CRCS if MODVERSIONS
+config X86_PIC
+ bool
+ prompt "Enable PIC modules"
+ depends on X86_64
+ default y
+ select MODULE_REL_CRCS if MODVERSIONS
+ ---help---
+ Compile position-independent modules which can
+ be placed anywhere in the 64-bit address space.
+
config RANDOMIZE_BASE_LARGE
bool "Increase the randomization range of the kernel image"
- depends on X86_64 && RANDOMIZE_BASE
+ depends on X86_64 && RANDOMIZE_BASE && X86_PIC
select X86_PIE
select X86_MODULE_PLTS if MODULES
default n
diff -uprN a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
--- a/arch/x86/kernel/alternative.c 2019-03-13 17:01:32.000000000 -0400
+++ b/arch/x86/kernel/alternative.c 2019-03-20 19:42:23.635815466 -0400
@@ -280,13 +280,14 @@ recompute_jump(struct alt_instr *a, u8 *
s32 n_dspl, o_dspl;
int repl_len;
- if (a->replacementlen != 5)
+ if (a->replacementlen != 5 && !(a->replacementlen == 6
+ && repl_insn[5] == 0x90)) /* NOP padded */
return;
o_dspl = *(s32 *)(insnbuf + 1);
/* next_rip of the replacement JMP */
- next_rip = repl_insn + a->replacementlen;
+ next_rip = repl_insn + 5;
/* target rip of the replacement JMP */
tgt_rip = next_rip + o_dspl;
n_dspl = tgt_rip - orig_insn;
@@ -311,7 +312,7 @@ two_byte_jmp:
insnbuf[0] = 0xeb;
insnbuf[1] = (s8)n_dspl;
- add_nops(insnbuf + 2, 3);
+ add_nops(insnbuf + 2, a->replacementlen - 2);
repl_len = 2;
goto done;
@@ -321,6 +322,7 @@ five_byte_jmp:
insnbuf[0] = 0xe9;
*(s32 *)&insnbuf[1] = n_dspl;
+ add_nops(insnbuf + 5, a->replacementlen - 5);
repl_len = 5;
@@ -406,16 +408,28 @@ void __init_or_module noinline apply_alt
insnbuf_sz = a->replacementlen;
/*
- * 0xe8 is a relative jump; fix the offset.
+ * 0xe8 is a relative CALL, fix the offset;
+ * also support the NOP padding for relaxed relocations.
+ *
+ * 0xff 0x15 and 0xff 0x25 are CALL/JMPs which use
+ * RIP-relative addresses; fix the offset for them as well.
*
* Instruction length is checked before the opcode to avoid
* accessing uninitialized bytes for zero-length replacements.
*/
- if (a->replacementlen == 5 && *insnbuf == 0xe8) {
+ if ((a->replacementlen == 5 && insnbuf[0] == 0xe8) ||
+ (a->replacementlen == 6 && insnbuf[0] == 0xe8
+ && insnbuf[5] == 0x90)) { /* NOP padded */
*(s32 *)(insnbuf + 1) += replacement - instr;
DPRINTK("Fix CALL offset: 0x%x, CALL 0x%lx",
*(s32 *)(insnbuf + 1),
(unsigned long)instr + *(s32 *)(insnbuf + 1) + 5);
+ } else if (a->replacementlen == 6 && insnbuf[0] == 0xff &&
+ (insnbuf[1] == 0x15 || insnbuf[1] == 0x25)) {
+ *(s32 *)(insnbuf + 2) += replacement - instr;
+ DPRINTK("Fix CALL/JMP(RIP) offset: 0x%x, CALL/JMP(RIP) 0x%lx",
+ *(s32 *)(insnbuf + 2),
+ (unsigned long)instr + *(s32 *)(insnbuf + 2) + 6);
}
if (a->replacementlen && is_jmp(replacement[0]))
diff -uprN a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
--- a/arch/x86/kernel/ftrace.c 2019-03-16 10:50:57.105692388 -0400
+++ b/arch/x86/kernel/ftrace.c 2019-03-20 19:42:23.635815466 -0400
@@ -144,13 +144,6 @@ ftrace_modify_initial_code(unsigned long
{
unsigned char replaced[MCOUNT_INSN_SIZE + 1];
- /*
- * If PIE is not enabled default to the original approach to code
- * modification.
- */
- if (!IS_ENABLED(CONFIG_X86_PIE))
- return ftrace_modify_code_direct(ip, old_code, new_code);
-
ftrace_expected = old_code;
/* Ensure the instructions point to a call to the GOT */
@@ -159,9 +152,12 @@ ftrace_modify_initial_code(unsigned long
return -EFAULT;
}
+ /*
+ * For non-PIC code, default to the original approach to code
+ * modification.
+ */
if (memcmp(replaced, got_call_preinsn, sizeof(got_call_preinsn))) {
- WARN_ONCE(1, "invalid function call");
- return -EINVAL;
+ return ftrace_modify_code_direct(ip, old_code, new_code);
}
/*
diff -uprN a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
--- a/arch/x86/kernel/Makefile 2019-03-16 10:50:57.097692208 -0400
+++ b/arch/x86/kernel/Makefile 2019-03-20 19:42:23.635815466 -0400
@@ -105,7 +105,8 @@ obj-$(CONFIG_KEXEC_CORE) += relocate_ker
obj-$(CONFIG_KEXEC_FILE) += kexec-bzimage64.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump_$(BITS).o
obj-y += kprobes/
-obj-$(CONFIG_MODULES) += module.o
+obj-$(CONFIG_MODULES) += module.o module-plt-stub.o
+OBJECT_FILES_NON_STANDARD_module-plt-stub.o := y
obj-$(CONFIG_DOUBLEFAULT) += doublefault.o
obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_VM86) += vm86_32.o
diff -uprN a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
--- a/arch/x86/kernel/module.c 2019-03-16 10:50:57.105692388 -0400
+++ b/arch/x86/kernel/module.c 2019-03-20 19:42:23.635815466 -0400
@@ -37,6 +37,9 @@
#include <asm/pgtable.h>
#include <asm/setup.h>
#include <asm/unwind.h>
+#include <asm/insn.h>
+
+static unsigned int module_plt_size;
#if 0
#define DEBUGP(fmt, ...) \
@@ -90,6 +93,17 @@ static u64 find_got_kernel_entry(Elf64_S
return 0;
}
+#else
+static u64 find_got_kernel_entry(Elf64_Sym *sym, const Elf64_Rela *rela)
+{
+ return 0;
+}
+#endif
+
+static inline bool is_local_symbol(Elf64_Sym *sym)
+{
+ return sym->st_shndx != SHN_UNDEF;
+}
static u64 module_emit_got_entry(struct module *mod, void *loc,
const Elf64_Rela *rela, Elf64_Sym *sym)
@@ -111,7 +125,7 @@ static u64 module_emit_got_entry(struct
* relocations are sorted, this will be the last entry we allocated.
* (if one exists).
*/
- if (i > 0 && got[i] == got[i - 2]) {
+ if (i > 0 && got[i] == got[i - 1]) {
ret = (u64)&got[i - 1];
} else {
gotsec->got_num_entries++;
@@ -119,7 +133,52 @@ static u64 module_emit_got_entry(struct
ret = (u64)&got[i];
}
- return ret + rela->r_addend;
+ return ret;
+}
+
+static bool plt_entries_equal(const struct plt_entry *a,
+ const struct plt_entry *b)
+{
+ void *a_val, *b_val;
+
+ a_val = (void *)a + (s64)a->rel_addr;
+ b_val = (void *)b + (s64)b->rel_addr;
+
+ return a_val == b_val;
+}
+
+static void get_plt_entry(struct plt_entry *plt_entry, struct module *mod,
+ void *loc, const Elf64_Rela *rela, Elf64_Sym *sym)
+{
+ u64 abs_val = module_emit_got_entry(mod, loc, rela, sym);
+ u32 rel_val = abs_val - (u64)&plt_entry->rel_addr
+ - sizeof(plt_entry->rel_addr);
+
+ memcpy(plt_entry, __THUNK_FOR_PLT, __THUNK_FOR_PLT_SIZE);
+ plt_entry->rel_addr = rel_val;
+}
+
+static u64 module_emit_plt_entry(struct module *mod, void *loc,
+ const Elf64_Rela *rela, Elf64_Sym *sym)
+{
+ struct mod_plt_sec *pltsec = &mod->arch.core_plt;
+ int i = pltsec->plt_num_entries;
+ void *plt = (void *)pltsec->plt->sh_addr + (u64)i * module_plt_size;
+
+ get_plt_entry(plt, mod, loc, rela, sym);
+
+ /*
+ * Check if the entry we just created is a duplicate. Given that the
+ * relocations are sorted, this will be the last entry we allocated.
+ * (if one exists).
+ */
+ if (i > 0 && plt_entries_equal(plt, plt - module_plt_size))
+ return (u64)(plt - module_plt_size);
+
+ pltsec->plt_num_entries++;
+ BUG_ON(pltsec->plt_num_entries > pltsec->plt_max_entries);
+
+ return (u64)plt;
}
#define cmp_3way(a, b) ((a) < (b) ? -1 : (a) > (b))
@@ -148,14 +207,17 @@ static bool duplicate_rel(const Elf64_Re
return num > 0 && cmp_rela(rela + num, rela + num - 1) == 0;
}
-static unsigned int count_gots(Elf64_Sym *syms, Elf64_Rela *rela, int num)
+static void count_gots_plts(unsigned long *num_got, unsigned long *num_plt,
+ Elf64_Sym *syms, Elf64_Rela *rela, int num)
{
- unsigned int ret = 0;
Elf64_Sym *s;
int i;
for (i = 0; i < num; i++) {
switch (ELF64_R_TYPE(rela[i].r_info)) {
+ case R_X86_64_PLT32:
+ case R_X86_64_REX_GOTPCRELX:
+ case R_X86_64_GOTPCRELX:
case R_X86_64_GOTPCREL:
s = syms + ELF64_R_SYM(rela[i].r_info);
@@ -164,12 +226,132 @@ static unsigned int count_gots(Elf64_Sym
* custom one for this module.
*/
if (!duplicate_rel(rela, i) &&
- !find_got_kernel_entry(s, rela + i))
- ret++;
+ !find_got_kernel_entry(s, rela + i)) {
+ (*num_got)++;
+ if (ELF64_R_TYPE(rela[i].r_info) ==
+ R_X86_64_PLT32 && !is_local_symbol(s))
+ (*num_plt)++;
+ }
break;
}
}
- return ret;
+}
+
+
+/*
+ * call *foo@...PCREL(%rip) ---> call foo nop
+ * jmp *foo@...PCREL(%rip) ---> jmp foo nop
+ */
+static int do_relax_GOTPCRELX(Elf64_Rela *rel, void *loc)
+{
+ struct insn insn;
+ void *ins_addr = loc - 2;
+
+ kernel_insn_init(&insn, ins_addr, MAX_INSN_SIZE);
+ insn_get_length(&insn);
+
+ /* 1 byte for opcode, 1 byte for modrm, 4 bytes for m32 */
+ if (insn.length != 6 || insn.opcode.value != 0xFF)
+ return -1;
+
+ switch (insn.modrm.value) {
+ case 0x15: /* CALL */
+ *(u8 *)ins_addr = 0xe8;
+ break;
+ case 0x25: /* JMP */
+ *(u8 *)ins_addr = 0xe9;
+ break;
+ default:
+ return -1;
+ }
+ memset(ins_addr + 1, 0, 4);
+ *((u8 *)ins_addr + 5) = 0x90; /* NOP */
+
+ /* Update the relocation */
+ rel->r_info &= ~ELF64_R_TYPE(~0LU);
+ rel->r_info |= R_X86_64_PC32;
+ rel->r_offset--;
+
+ return 0;
+}
+
+
+/*
+ * mov foo@...PCREL(%rip), %reg ---> lea foo(%rip), %reg
+ * */
+static int do_relax_REX_GOTPCRELX(Elf64_Rela *rel, void *loc)
+{
+ struct insn insn;
+ void *ins_addr = loc - 3;
+
+ kernel_insn_init(&insn, ins_addr, MAX_INSN_SIZE);
+ insn_get_length(&insn);
+
+ /* 1 byte for REX, 1 byte for opcode, 1 byte for modrm,
+ * 4 bytes for m32.
+ */
+ if (insn.length != 7)
+ return -1;
+
+ /* Not the MOV instruction, could be ADD, SUB etc. */
+ if (insn.opcode.value != 0x8b)
+ return 0;
+ *((u8 *)ins_addr + 1) = 0x8d; /* LEA */
+
+ /* Update the relocation. */
+ rel->r_info &= ~ELF64_R_TYPE(~0LU);
+ rel->r_info |= R_X86_64_PC32;
+
+ return 0;
+}
+
+static int apply_relaxations(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
+ struct module *mod)
+{
+ Elf64_Sym *syms = NULL;
+ int i, j;
+
+ for (i = 0; i < ehdr->e_shnum; i++) {
+ if (sechdrs[i].sh_type == SHT_SYMTAB)
+ syms = (Elf64_Sym *)sechdrs[i].sh_addr;
+ }
+
+ if (!syms) {
+ pr_err("%s: module symtab section missing\n", mod->name);
+ return -ENOEXEC;
+ }
+
+ for (i = 0; i < ehdr->e_shnum; i++) {
+ Elf64_Rela *rels = (void *)ehdr + sechdrs[i].sh_offset;
+
+ if (sechdrs[i].sh_type != SHT_RELA)
+ continue;
+
+ for (j = 0; j < sechdrs[i].sh_size / sizeof(*rels); j++) {
+ Elf64_Rela *rel = &rels[j];
+ Elf64_Sym *sym = &syms[ELF64_R_SYM(rel->r_info)];
+ void *loc = (void *)sechdrs[sechdrs[i].sh_info].sh_addr
+ + rel->r_offset;
+
+ if (is_local_symbol(sym)) {
+ switch (ELF64_R_TYPE(rel->r_info)) {
+ case R_X86_64_GOTPCRELX:
+ if (do_relax_GOTPCRELX(rel, loc))
+ BUG();
+ break;
+ case R_X86_64_REX_GOTPCRELX:
+ if (do_relax_REX_GOTPCRELX(rel, loc))
+ BUG();
+ break;
+ case R_X86_64_GOTPCREL:
+ /* cannot be relaxed, ignore it */
+ break;
+ }
+ }
+ }
+ }
+
+ return 0;
}
/*
@@ -179,29 +361,42 @@ static unsigned int count_gots(Elf64_Sym
int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
char *secstrings, struct module *mod)
{
- unsigned long gots = 0;
+ unsigned long num_got = 0;
+ unsigned long num_plt = 0;
Elf_Shdr *symtab = NULL;
Elf64_Sym *syms = NULL;
char *strings, *name;
- int i;
+ int i, got_idx = -1;
+
+ apply_relaxations(ehdr, sechdrs, mod);
/*
- * Find the empty .got section so we can expand it to store the PLT
- * entries. Record the symtab address as well.
+ * Find the empty .got and .plt sections so we can expand it
+ * to store the GOT and PLT entries.
+ * Record the symtab address as well.
*/
for (i = 0; i < ehdr->e_shnum; i++) {
if (!strcmp(secstrings + sechdrs[i].sh_name, ".got")) {
- mod->arch.core.got = sechdrs + i;
+ got_idx = i;
+ } else if (!strcmp(secstrings + sechdrs[i].sh_name, ".plt")) {
+ mod->arch.core_plt.plt = sechdrs + i;
} else if (sechdrs[i].sh_type == SHT_SYMTAB) {
symtab = sechdrs + i;
syms = (Elf64_Sym *)symtab->sh_addr;
}
}
- if (!mod->arch.core.got) {
+ if (got_idx < 0) {
pr_err("%s: module GOT section missing\n", mod->name);
return -ENOEXEC;
}
+
+ mod->arch.core.got = sechdrs + got_idx;
+
+ if (!mod->arch.core_plt.plt) {
+ pr_err("%s: module PLT section missing\n", mod->name);
+ return -ENOEXEC;
+ }
if (!syms) {
pr_err("%s: module symtab section missing\n", mod->name);
return -ENOEXEC;
@@ -217,33 +412,36 @@ int module_frob_arch_sections(Elf_Ehdr *
/* sort by type, symbol index and addend */
sort(rels, numrels, sizeof(Elf64_Rela), cmp_rela, NULL);
- gots += count_gots(syms, rels, numrels);
+ count_gots_plts(&num_got, &num_plt, syms, rels, numrels);
}
mod->arch.core.got->sh_type = SHT_NOBITS;
mod->arch.core.got->sh_flags = SHF_ALLOC;
mod->arch.core.got->sh_addralign = L1_CACHE_BYTES;
- mod->arch.core.got->sh_size = (gots + 1) * sizeof(u64);
+ mod->arch.core.got->sh_size = (num_got + 1) * sizeof(u64);
mod->arch.core.got_num_entries = 0;
- mod->arch.core.got_max_entries = gots;
+ mod->arch.core.got_max_entries = num_got;
+
+ module_plt_size = ALIGN(__THUNK_FOR_PLT_SIZE, PLT_ENTRY_ALIGNMENT);
+ mod->arch.core_plt.plt->sh_type = SHT_NOBITS;
+ mod->arch.core_plt.plt->sh_flags = SHF_EXECINSTR | SHF_ALLOC;
+ mod->arch.core_plt.plt->sh_addralign = L1_CACHE_BYTES;
+ mod->arch.core_plt.plt->sh_size = (num_plt + 1) * module_plt_size;
+ mod->arch.core_plt.plt_num_entries = 0;
+ mod->arch.core_plt.plt_max_entries = num_plt;
- /*
- * If a _GLOBAL_OFFSET_TABLE_ symbol exists, make it absolute for
- * modules to correctly reference it. Similar to s390 implementation.
- */
strings = (void *) ehdr + sechdrs[symtab->sh_link].sh_offset;
for (i = 0; i < symtab->sh_size/sizeof(Elf_Sym); i++) {
if (syms[i].st_shndx != SHN_UNDEF)
continue;
name = strings + syms[i].st_name;
if (!strcmp(name, "_GLOBAL_OFFSET_TABLE_")) {
- syms[i].st_shndx = SHN_ABS;
+ syms[i].st_shndx = got_idx;
break;
}
}
return 0;
}
-#endif
void *module_alloc(unsigned long size)
{
@@ -306,6 +504,29 @@ int apply_relocate(Elf32_Shdr *sechdrs,
return 0;
}
#else /*X86_64*/
+
+int check_relocation_pic_safe(Elf64_Rela *rel, Elf64_Sym *sym,
+ const char *strtab, struct module *mod)
+{
+ bool isLocalSym = is_local_symbol(sym);
+
+ switch (ELF64_R_TYPE(rel->r_info)) {
+ case R_X86_64_32:
+ case R_X86_64_32S:
+ case R_X86_64_PC32:
+ if (!isLocalSym)
+ goto fail;
+ break;
+ }
+
+ return 0;
+
+fail:
+ pr_err("Non PIC Relocation in `%s', relocation type %d, symbol %s\n",
+ mod->name, (int)ELF64_R_TYPE(rel->r_info), &strtab[sym->st_name]);
+ return -1;
+}
+
int apply_relocate_add(Elf64_Shdr *sechdrs,
const char *strtab,
unsigned int symindex,
@@ -330,6 +551,10 @@ int apply_relocate_add(Elf64_Shdr *sechd
sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
+ ELF64_R_SYM(rel[i].r_info);
+#ifdef CONFIG_X86_PIC
+ BUG_ON(check_relocation_pic_safe(&rel[i], sym, strtab, me));
+#endif
+
DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
(int)ELF64_R_TYPE(rel[i].r_info),
sym->st_value, rel[i].r_addend, (u64)loc);
@@ -358,18 +583,25 @@ int apply_relocate_add(Elf64_Shdr *sechd
if ((s64)val != *(s32 *)loc)
goto overflow;
break;
-#ifdef CONFIG_X86_PIE
+ case R_X86_64_PLT32:
+ if (!is_local_symbol(sym))
+ val = module_emit_plt_entry(me, loc, rel + i,
+ sym) + rel[i].r_addend;
+ goto pc32_reloc;
+ case R_X86_64_REX_GOTPCRELX:
+ case R_X86_64_GOTPCRELX:
case R_X86_64_GOTPCREL:
- val = module_emit_got_entry(me, loc, rel + i, sym);
+ val = module_emit_got_entry(me, loc, rel + i, sym)
+ + rel[i].r_addend;
/* fallthrough */
-#endif
case R_X86_64_PC32:
- case R_X86_64_PLT32:
+pc32_reloc:
if (*(u32 *)loc != 0)
goto invalid_relocation;
val -= (u64)loc;
*(u32 *)loc = val;
- if (IS_ENABLED(CONFIG_X86_PIE) &&
+ if ((IS_ENABLED(CONFIG_X86_PIE) ||
+ IS_ENABLED(CONFIG_X86_PIC)) &&
(s64)val != *(s32 *)loc)
goto overflow;
break;
diff -uprN a/arch/x86/kernel/module.lds b/arch/x86/kernel/module.lds
--- a/arch/x86/kernel/module.lds 2019-03-16 10:50:57.105692388 -0400
+++ b/arch/x86/kernel/module.lds 2019-03-20 19:42:23.635815466 -0400
@@ -1,3 +1,4 @@
SECTIONS {
.got (NOLOAD) : { BYTE(0) }
+ .plt (NOLOAD) : { BYTE(0) }
}
diff -uprN a/arch/x86/kernel/module-plt-stub.S
b/arch/x86/kernel/module-plt-stub.S
--- a/arch/x86/kernel/module-plt-stub.S 1969-12-31 19:00:00.000000000 -0500
+++ b/arch/x86/kernel/module-plt-stub.S 2019-03-20 19:42:23.635815466 -0400
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/stringify.h>
+#include <linux/linkage.h>
+#include <asm/dwarf2.h>
+#include <asm/cpufeatures.h>
+#include <asm/alternative-asm.h>
+#include <asm/export.h>
+#include <asm/nospec-branch.h>
+
+/* The following code is used for PLT generation only
+ and should never be executed directly. */
+.section .rodata
+.globl __THUNK_FOR_PLT
+.globl __THUNK_FOR_PLT_SIZE
+__THUNK_FOR_PLT:
+#ifdef CONFIG_RETPOLINE
+ movq 0(%rip), %rax
+ JMP_NOSPEC %rax
+#else
+ jmpq *0(%rip)
+#endif
+__THUNK_FOR_PLT_SIZE: .long . - __THUNK_FOR_PLT
diff -uprN a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
--- a/arch/x86/kvm/emulate.c 2019-03-13 17:01:32.000000000 -0400
+++ b/arch/x86/kvm/emulate.c 2019-03-20 19:42:23.635815466 -0400
@@ -428,7 +428,6 @@ static int fastop(struct x86_emulate_ctx
FOP_RET
asm(".pushsection .fixup, \"ax\"\n"
- ".global kvm_fastop_exception \n"
"kvm_fastop_exception: xor %esi, %esi; ret\n"
".popsection");
diff -uprN a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S
--- a/arch/x86/kvm/vmx/vmenter.S 2019-03-13 17:01:32.000000000 -0400
+++ b/arch/x86/kvm/vmx/vmenter.S 2019-03-20 19:42:23.635815466 -0400
@@ -18,6 +18,17 @@
* they VM-Fail, whereas a successful VM-Enter + VM-Exit will jump
* to vmx_vmexit.
*/
+#if defined(MODULE) && defined(CONFIG_X86_PIC)
+# define ____kvm_check_rebooting \
+ pushq %rax; \
+ movq kvm_rebooting@...PCREL(%rip), %rax; \
+ cmpb $0, (%rax); \
+ popq %rax
+#else
+# define ____kvm_check_rebooting \
+ cmpb $0, kvm_rebooting(%rip)
+#endif
+
ENTRY(vmx_vmenter)
/* EFLAGS.ZF is set if VMCS.LAUNCHED == 0 */
je 2f
@@ -28,9 +39,9 @@ ENTRY(vmx_vmenter)
2: vmlaunch
ret
-3: cmpb $0, kvm_rebooting
+3: ____kvm_check_rebooting
jne 4f
- call kvm_spurious_fault
+ _ASM_CALL(kvm_spurious_fault)
4: ret
.pushsection .fixup, "ax"
diff -uprN a/arch/x86/Makefile b/arch/x86/Makefile
--- a/arch/x86/Makefile 2019-03-16 10:50:57.109692478 -0400
+++ b/arch/x86/Makefile 2019-03-20 19:42:23.635815466 -0400
@@ -131,6 +131,17 @@ else
KBUILD_CFLAGS += $(cflags-y)
KBUILD_CFLAGS += -mno-red-zone
+
+ifdef CONFIG_X86_PIC
+ KBUILD_CFLAGS_MODULE += -fPIC -mcmodel=small
-fno-stack-protector -fvisibility=hidden
+ ifdef CONFIG_RETPOLINE
+ MOD_EXTRA_LINK += $(srctree)/arch/$(SRCARCH)/module-lib/retpoline.o
+ else
+ KBUILD_CFLAGS_MODULE += -fno-plt
+ endif
+endif
+ KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/x86/kernel/module.lds
+
ifdef CONFIG_X86_PIE
KBUILD_CFLAGS += -fPIE
KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/x86/kernel/module.lds
diff -uprN a/arch/x86/module-lib/Makefile b/arch/x86/module-lib/Makefile
--- a/arch/x86/module-lib/Makefile 1969-12-31 19:00:00.000000000 -0500
+++ b/arch/x86/module-lib/Makefile 2019-03-20 19:42:23.635815466 -0400
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_RETPOLINE) += retpoline.o
\ No newline at end of file
diff -uprN a/arch/x86/module-lib/retpoline.S
b/arch/x86/module-lib/retpoline.S
--- a/arch/x86/module-lib/retpoline.S 1969-12-31 19:00:00.000000000 -0500
+++ b/arch/x86/module-lib/retpoline.S 2019-03-20 19:42:23.635815466 -0400
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/stringify.h>
+#include <linux/linkage.h>
+#include <asm/dwarf2.h>
+#include <asm/cpufeatures.h>
+#include <asm/alternative-asm.h>
+#include <asm/export.h>
+#include <asm/nospec-branch.h>
+
+.macro THUNK reg
+ .section .text.__x86.indirect_thunk
+
+ENTRY(__x86_indirect_thunk_\reg)
+ CFI_STARTPROC
+ JMP_NOSPEC %\reg
+ CFI_ENDPROC
+ENDPROC(__x86_indirect_thunk_\reg)
+.endm
+
+/*
+ * Despite being an assembler file we can't just use .irp here
+ * because __KSYM_DEPS__ only uses the C preprocessor and would
+ * only see one instance of "__x86_indirect_thunk_\reg" rather
+ * than one per register with the correct names. So we do it
+ * the simple and nasty way...
+ */
+#define GENERATE_THUNK(reg) THUNK reg
+
+GENERATE_THUNK(_ASM_AX)
+GENERATE_THUNK(_ASM_BX)
+GENERATE_THUNK(_ASM_CX)
+GENERATE_THUNK(_ASM_DX)
+GENERATE_THUNK(_ASM_SI)
+GENERATE_THUNK(_ASM_DI)
+GENERATE_THUNK(_ASM_BP)
+#ifdef CONFIG_64BIT
+GENERATE_THUNK(r8)
+GENERATE_THUNK(r9)
+GENERATE_THUNK(r10)
+GENERATE_THUNK(r11)
+GENERATE_THUNK(r12)
+GENERATE_THUNK(r13)
+GENERATE_THUNK(r14)
+GENERATE_THUNK(r15)
+#endif
+
diff -uprN a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
--- a/arch/x86/tools/relocs.c 2019-03-16 10:50:57.109692478 -0400
+++ b/arch/x86/tools/relocs.c 2019-03-20 19:42:23.635815466 -0400
@@ -212,6 +212,8 @@ static const char *rel_type(unsigned typ
REL_TYPE(R_X86_64_JUMP_SLOT),
REL_TYPE(R_X86_64_RELATIVE),
REL_TYPE(R_X86_64_GOTPCREL),
+ REL_TYPE(R_X86_64_REX_GOTPCRELX),
+ REL_TYPE(R_X86_64_GOTPCRELX),
REL_TYPE(R_X86_64_32),
REL_TYPE(R_X86_64_32S),
REL_TYPE(R_X86_64_16),
@@ -871,6 +873,8 @@ static int do_reloc64(struct section *se
offset += per_cpu_load_addr;
switch (r_type) {
+ case R_X86_64_REX_GOTPCRELX:
+ case R_X86_64_GOTPCRELX:
case R_X86_64_GOTPCREL:
case R_X86_64_NONE:
/* NONE can be ignored. */
diff -uprN a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
--- a/arch/x86/xen/xen-head.S 2019-03-16 10:50:57.101692298 -0400
+++ b/arch/x86/xen/xen-head.S 2019-03-20 19:42:23.635815466 -0400
@@ -13,6 +13,7 @@
#include <asm/page_types.h>
#include <asm/percpu.h>
#include <asm/unwind_hints.h>
+#include <asm/export.h>
#include <xen/interface/elfnote.h>
#include <xen/interface/features.h>
@@ -66,6 +67,7 @@ ENTRY(hypercall_page)
.endr
#define HYPERCALL(n) \
+ EXPORT_SYMBOL_GPL(xen_hypercall_##n); \
.equ xen_hypercall_##n, hypercall_page + __HYPERVISOR_##n * 32; \
.type xen_hypercall_##n, @function; .size xen_hypercall_##n, 32
#include <asm/xen-hypercalls.h>
diff -uprN a/Makefile b/Makefile
--- a/Makefile 2019-03-16 10:50:57.109692478 -0400
+++ b/Makefile 2019-03-20 19:42:23.635815466 -0400
@@ -1259,10 +1259,10 @@ all: modules
# using awk while concatenating to the final file.
PHONY += modules
-modules: $(vmlinux-dirs) $(if $(KBUILD_BUILTIN),vmlinux) modules.builtin
+modules: $(vmlinux-dirs) $(if $(KBUILD_BUILTIN),vmlinux)
modules.builtin $(MOD_EXTRA_LINK)
$(Q)$(AWK) '!x[$$0]++' $(vmlinux-dirs:%=$(objtree)/%/modules.order) >
$(objtree)/modules.order
@$(kecho) ' Building modules, stage 2.';
- $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
+ $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
MOD_EXTRA_LINK=$(MOD_EXTRA_LINK)
modules.builtin: $(vmlinux-dirs:%=%/modules.builtin)
$(Q)$(AWK) '!x[$$0]++' $^ > $(objtree)/modules.builtin
@@ -1273,7 +1273,7 @@ modules.builtin: $(vmlinux-dirs:%=%/modu
# Target to prepare building external modules
PHONY += modules_prepare
-modules_prepare: prepare
+modules_prepare: prepare $(MOD_EXTRA_LINK)
# Target to install modules
PHONY += modules_install
@@ -1557,7 +1557,7 @@ $(module-dirs): prepare $(objtree)/Modul
modules: $(module-dirs)
@$(kecho) ' Building modules, stage 2.';
- $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
+ $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
MOD_EXTRA_LINK=$(MOD_EXTRA_LINK)
PHONY += modules_install
modules_install: _emodinst_ _emodinst_post
diff -uprN a/scripts/Makefile.modpost b/scripts/Makefile.modpost
--- a/scripts/Makefile.modpost 2019-03-13 17:01:32.000000000 -0400
+++ b/scripts/Makefile.modpost 2019-03-20 19:42:23.635815466 -0400
@@ -125,7 +125,7 @@ quiet_cmd_ld_ko_o = LD [M] $@
-o $@ $(filter-out FORCE,$^) ; \
$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
-$(modules): %.ko :%.o %.mod.o FORCE
+$(modules): %.ko :%.o %.mod.o $(MOD_EXTRA_LINK) FORCE
+$(call if_changed,ld_ko_o)
targets += $(modules)
diff -uprN a/scripts/recordmcount.c b/scripts/recordmcount.c
--- a/scripts/recordmcount.c 2019-03-16 10:50:57.105692388 -0400
+++ b/scripts/recordmcount.c 2019-03-20 19:42:23.635815466 -0400
@@ -452,7 +452,8 @@ static int make_nop_x86(void *map, size_
/* Swap the stub and nop for a got call if the binary is built with PIE */
static int is_fake_mcount_x86_x64(Elf64_Rel const *rp)
{
- if (ELF64_R_TYPE(rp->r_info) == R_X86_64_GOTPCREL) {
+ if (ELF64_R_TYPE(rp->r_info) == R_X86_64_GOTPCREL ||
+ ELF64_R_TYPE(rp->r_info) == R_X86_64_GOTPCRELX) {
ideal_nop = ideal_nop6_x86_64;
ideal_nop_x86_size = sizeof(ideal_nop6_x86_64);
stub_x86 = stub_got_x86;
diff -uprN a/tools/objtool/check.c b/tools/objtool/check.c
--- a/tools/objtool/check.c 2019-03-13 17:01:32.000000000 -0400
+++ b/tools/objtool/check.c 2019-03-20 19:42:23.635815466 -0400
@@ -179,7 +179,7 @@ static int __dead_end_function(struct ob
return 0;
insn = find_insn(file, func->sec, func->offset);
- if (!insn->func)
+ if (!insn || !insn->func)
return 0;
func_for_each_insn_all(file, func, insn) {
@@ -233,6 +233,8 @@ static int __dead_end_function(struct ob
static int dead_end_function(struct objtool_file *file, struct symbol
*func)
{
+ if (!func)
+ return 0;
return __dead_end_function(file, func, 0);
}
@@ -581,7 +583,7 @@ static int add_call_destinations(struct
struct rela *rela;
for_each_insn(file, insn) {
- if (insn->type != INSN_CALL)
+ if (insn->type != INSN_CALL && insn->type != INSN_CALL_DYNAMIC)
continue;
rela = find_rela_by_dest_range(insn->sec, insn->offset,
@@ -590,8 +592,8 @@ static int add_call_destinations(struct
dest_off = insn->offset + insn->len + insn->immediate;
insn->call_dest = find_symbol_by_offset(insn->sec,
dest_off);
-
- if (!insn->call_dest && !insn->ignore) {
+ if (!insn->call_dest && !insn->ignore &&
+ insn->type != INSN_CALL_DYNAMIC) {
WARN_FUNC("unsupported intra-function call",
insn->sec, insn->offset);
if (retpoline)
@@ -602,8 +604,9 @@ static int add_call_destinations(struct
} else if (rela->sym->type == STT_SECTION) {
insn->call_dest = find_symbol_by_offset(rela->sym->sec,
rela->addend+4);
- if (!insn->call_dest ||
- insn->call_dest->type != STT_FUNC) {
+ if ((!insn->call_dest ||
+ insn->call_dest->type != STT_FUNC) &&
+ insn->type != INSN_CALL_DYNAMIC) {
WARN_FUNC("can't find call dest symbol at %s+0x%x",
insn->sec, insn->offset,
rela->sym->sec->name,
@@ -836,6 +839,12 @@ static int add_switch_table(struct objto
struct symbol *pfunc = insn->func->pfunc;
unsigned int prev_offset = 0;
+ /* If PC32 relocations are used (as in PIC), the following logic
+ * can be broken in many ways.
+ */
+ if (file->ignore_unreachables)
+ return 0;
+
list_for_each_entry_from(rela, &table->rela_sec->rela_list, list) {
if (rela == next_table)
break;
@@ -1272,7 +1281,7 @@ static int decode_sections(struct objtoo
static bool is_fentry_call(struct instruction *insn)
{
- if (insn->type == INSN_CALL &&
+ if (insn->call_dest &&
insn->call_dest->type == STT_NOTYPE &&
!strcmp(insn->call_dest->name, "__fentry__"))
return true;
@@ -1917,6 +1926,7 @@ static int validate_branch(struct objtoo
return 0;
case INSN_CALL:
+ case INSN_CALL_DYNAMIC:
if (is_fentry_call(insn))
break;
@@ -1926,8 +1936,6 @@ static int validate_branch(struct objtoo
if (ret == -1)
return 1;
- /* fallthrough */
- case INSN_CALL_DYNAMIC:
if (!no_fp && func && !has_valid_stack_frame(&state)) {
WARN_FUNC("call without frame pointer save/setup",
sec, insn->offset);
@@ -1957,12 +1965,15 @@ static int validate_branch(struct objtoo
break;
case INSN_JUMP_DYNAMIC:
+ /* XXX: Does not work properly with PIC code. */
+#if 0
if (func && list_empty(&insn->alts) &&
has_modified_stack_frame(&state)) {
WARN_FUNC("sibling call from callable instruction with modified
stack frame",
sec, insn->offset);
return 1;
}
+#endif
return 0;
@@ -2043,6 +2054,11 @@ static int validate_retpoline(struct obj
if (!strcmp(insn->sec->name, ".init.text") && !module)
continue;
+ /* ignore ftrace calls in PIC code */
+ if (!insn->call_dest ||
+ !strcmp(insn->call_dest->name, "__fentry__"))
+ continue;
+
WARN_FUNC("indirect %s found in RETPOLINE build",
insn->sec, insn->offset,
insn->type == INSN_JUMP_DYNAMIC ? "jump" : "call");
@@ -2055,13 +2071,15 @@ static int validate_retpoline(struct obj
static bool is_kasan_insn(struct instruction *insn)
{
- return (insn->type == INSN_CALL &&
+ return ((insn->type == INSN_CALL || insn->type == INSN_CALL_DYNAMIC) &&
+ insn->call_dest &&
!strcmp(insn->call_dest->name, "__asan_handle_no_return"));
}
static bool is_ubsan_insn(struct instruction *insn)
{
- return (insn->type == INSN_CALL &&
+ return ((insn->type == INSN_CALL || insn->type == INSN_CALL_DYNAMIC) &&
+ insn->call_dest &&
!strcmp(insn->call_dest->name,
"__ubsan_handle_builtin_unreachable"));
}
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