mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-25 02:09:42 +00:00
arm: use fixmap for text patching when text is RO
Use fixmaps for text patching when the kernel text is read-only, inspired by x86. This makes jump labels and kprobes work with the currently available CONFIG_DEBUG_SET_MODULE_RONX and the upcoming CONFIG_DEBUG_RODATA options. Signed-off-by: Rabin Vincent <rabin@rab.in> [kees: fixed up for merge with "arm: use generic fixmap.h"] [kees: added parse acquire/release annotations to pass C=1 builds] [kees: always use stop_machine to keep TLB flushing local] Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Nicolas Pitre <nico@linaro.org>
This commit is contained in:
parent
99b4ac9afc
commit
ab0615e2d6
4 changed files with 89 additions and 21 deletions
|
@ -11,6 +11,10 @@ enum fixed_addresses {
|
||||||
FIX_KMAP_BEGIN,
|
FIX_KMAP_BEGIN,
|
||||||
FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1,
|
FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1,
|
||||||
|
|
||||||
|
/* Support writing RO kernel text via kprobes, jump labels, etc. */
|
||||||
|
FIX_TEXT_POKE0,
|
||||||
|
FIX_TEXT_POKE1,
|
||||||
|
|
||||||
__end_of_fixed_addresses
|
__end_of_fixed_addresses
|
||||||
};
|
};
|
||||||
|
|
||||||
|
|
|
@ -19,7 +19,7 @@ static void __arch_jump_label_transform(struct jump_entry *entry,
|
||||||
insn = arm_gen_nop();
|
insn = arm_gen_nop();
|
||||||
|
|
||||||
if (is_static)
|
if (is_static)
|
||||||
__patch_text(addr, insn);
|
__patch_text_early(addr, insn);
|
||||||
else
|
else
|
||||||
patch_text(addr, insn);
|
patch_text(addr, insn);
|
||||||
}
|
}
|
||||||
|
|
|
@ -1,8 +1,11 @@
|
||||||
#include <linux/kernel.h>
|
#include <linux/kernel.h>
|
||||||
|
#include <linux/spinlock.h>
|
||||||
#include <linux/kprobes.h>
|
#include <linux/kprobes.h>
|
||||||
|
#include <linux/mm.h>
|
||||||
#include <linux/stop_machine.h>
|
#include <linux/stop_machine.h>
|
||||||
|
|
||||||
#include <asm/cacheflush.h>
|
#include <asm/cacheflush.h>
|
||||||
|
#include <asm/fixmap.h>
|
||||||
#include <asm/smp_plat.h>
|
#include <asm/smp_plat.h>
|
||||||
#include <asm/opcodes.h>
|
#include <asm/opcodes.h>
|
||||||
|
|
||||||
|
@ -13,21 +16,77 @@ struct patch {
|
||||||
unsigned int insn;
|
unsigned int insn;
|
||||||
};
|
};
|
||||||
|
|
||||||
void __kprobes __patch_text(void *addr, unsigned int insn)
|
static DEFINE_SPINLOCK(patch_lock);
|
||||||
|
|
||||||
|
static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags)
|
||||||
|
__acquires(&patch_lock)
|
||||||
|
{
|
||||||
|
unsigned int uintaddr = (uintptr_t) addr;
|
||||||
|
bool module = !core_kernel_text(uintaddr);
|
||||||
|
struct page *page;
|
||||||
|
|
||||||
|
if (module && IS_ENABLED(CONFIG_DEBUG_SET_MODULE_RONX))
|
||||||
|
page = vmalloc_to_page(addr);
|
||||||
|
else if (!module && IS_ENABLED(CONFIG_DEBUG_RODATA))
|
||||||
|
page = virt_to_page(addr);
|
||||||
|
else
|
||||||
|
return addr;
|
||||||
|
|
||||||
|
if (flags)
|
||||||
|
spin_lock_irqsave(&patch_lock, *flags);
|
||||||
|
else
|
||||||
|
__acquire(&patch_lock);
|
||||||
|
|
||||||
|
set_fixmap(fixmap, page_to_phys(page));
|
||||||
|
|
||||||
|
return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
|
||||||
|
}
|
||||||
|
|
||||||
|
static void __kprobes patch_unmap(int fixmap, unsigned long *flags)
|
||||||
|
__releases(&patch_lock)
|
||||||
|
{
|
||||||
|
clear_fixmap(fixmap);
|
||||||
|
|
||||||
|
if (flags)
|
||||||
|
spin_unlock_irqrestore(&patch_lock, *flags);
|
||||||
|
else
|
||||||
|
__release(&patch_lock);
|
||||||
|
}
|
||||||
|
|
||||||
|
void __kprobes __patch_text_real(void *addr, unsigned int insn, bool remap)
|
||||||
{
|
{
|
||||||
bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL);
|
bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL);
|
||||||
|
unsigned int uintaddr = (uintptr_t) addr;
|
||||||
|
bool twopage = false;
|
||||||
|
unsigned long flags;
|
||||||
|
void *waddr = addr;
|
||||||
int size;
|
int size;
|
||||||
|
|
||||||
|
if (remap)
|
||||||
|
waddr = patch_map(addr, FIX_TEXT_POKE0, &flags);
|
||||||
|
else
|
||||||
|
__acquire(&patch_lock);
|
||||||
|
|
||||||
if (thumb2 && __opcode_is_thumb16(insn)) {
|
if (thumb2 && __opcode_is_thumb16(insn)) {
|
||||||
*(u16 *)addr = __opcode_to_mem_thumb16(insn);
|
*(u16 *)waddr = __opcode_to_mem_thumb16(insn);
|
||||||
size = sizeof(u16);
|
size = sizeof(u16);
|
||||||
} else if (thumb2 && ((uintptr_t)addr & 2)) {
|
} else if (thumb2 && (uintaddr & 2)) {
|
||||||
u16 first = __opcode_thumb32_first(insn);
|
u16 first = __opcode_thumb32_first(insn);
|
||||||
u16 second = __opcode_thumb32_second(insn);
|
u16 second = __opcode_thumb32_second(insn);
|
||||||
u16 *addrh = addr;
|
u16 *addrh0 = waddr;
|
||||||
|
u16 *addrh1 = waddr + 2;
|
||||||
|
|
||||||
addrh[0] = __opcode_to_mem_thumb16(first);
|
twopage = (uintaddr & ~PAGE_MASK) == PAGE_SIZE - 2;
|
||||||
addrh[1] = __opcode_to_mem_thumb16(second);
|
if (twopage && remap)
|
||||||
|
addrh1 = patch_map(addr + 2, FIX_TEXT_POKE1, NULL);
|
||||||
|
|
||||||
|
*addrh0 = __opcode_to_mem_thumb16(first);
|
||||||
|
*addrh1 = __opcode_to_mem_thumb16(second);
|
||||||
|
|
||||||
|
if (twopage && addrh1 != addr + 2) {
|
||||||
|
flush_kernel_vmap_range(addrh1, 2);
|
||||||
|
patch_unmap(FIX_TEXT_POKE1, NULL);
|
||||||
|
}
|
||||||
|
|
||||||
size = sizeof(u32);
|
size = sizeof(u32);
|
||||||
} else {
|
} else {
|
||||||
|
@ -36,10 +95,16 @@ void __kprobes __patch_text(void *addr, unsigned int insn)
|
||||||
else
|
else
|
||||||
insn = __opcode_to_mem_arm(insn);
|
insn = __opcode_to_mem_arm(insn);
|
||||||
|
|
||||||
*(u32 *)addr = insn;
|
*(u32 *)waddr = insn;
|
||||||
size = sizeof(u32);
|
size = sizeof(u32);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
if (waddr != addr) {
|
||||||
|
flush_kernel_vmap_range(waddr, twopage ? size / 2 : size);
|
||||||
|
patch_unmap(FIX_TEXT_POKE0, &flags);
|
||||||
|
} else
|
||||||
|
__release(&patch_lock);
|
||||||
|
|
||||||
flush_icache_range((uintptr_t)(addr),
|
flush_icache_range((uintptr_t)(addr),
|
||||||
(uintptr_t)(addr) + size);
|
(uintptr_t)(addr) + size);
|
||||||
}
|
}
|
||||||
|
@ -60,16 +125,5 @@ void __kprobes patch_text(void *addr, unsigned int insn)
|
||||||
.insn = insn,
|
.insn = insn,
|
||||||
};
|
};
|
||||||
|
|
||||||
if (cache_ops_need_broadcast()) {
|
stop_machine(patch_text_stop_machine, &patch, NULL);
|
||||||
stop_machine(patch_text_stop_machine, &patch, cpu_online_mask);
|
|
||||||
} else {
|
|
||||||
bool straddles_word = IS_ENABLED(CONFIG_THUMB2_KERNEL)
|
|
||||||
&& __opcode_is_thumb32(insn)
|
|
||||||
&& ((uintptr_t)addr & 2);
|
|
||||||
|
|
||||||
if (straddles_word)
|
|
||||||
stop_machine(patch_text_stop_machine, &patch, NULL);
|
|
||||||
else
|
|
||||||
__patch_text(addr, insn);
|
|
||||||
}
|
|
||||||
}
|
}
|
||||||
|
|
|
@ -2,6 +2,16 @@
|
||||||
#define _ARM_KERNEL_PATCH_H
|
#define _ARM_KERNEL_PATCH_H
|
||||||
|
|
||||||
void patch_text(void *addr, unsigned int insn);
|
void patch_text(void *addr, unsigned int insn);
|
||||||
void __patch_text(void *addr, unsigned int insn);
|
void __patch_text_real(void *addr, unsigned int insn, bool remap);
|
||||||
|
|
||||||
|
static inline void __patch_text(void *addr, unsigned int insn)
|
||||||
|
{
|
||||||
|
__patch_text_real(addr, insn, true);
|
||||||
|
}
|
||||||
|
|
||||||
|
static inline void __patch_text_early(void *addr, unsigned int insn)
|
||||||
|
{
|
||||||
|
__patch_text_real(addr, insn, false);
|
||||||
|
}
|
||||||
|
|
||||||
#endif
|
#endif
|
||||||
|
|
Loading…
Reference in a new issue