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kprobes: Prohibit probing on .entry.text code

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.entry.text is a code area which is used for interrupt/syscall
entries, which includes many sensitive code.
Thus, it is better to prohibit probing on all of such code
instead of a part of that.
Since some symbols are already registered on kprobe blacklist,
this also removes them from the blacklist.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Jonathan Lebon <jlebon@redhat.com>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/20140417081658.26341.57354.stgit@ltc230.yrl.intra.hitachi.co.jp
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Masami Hiramatsu 2014-04-17 17:16:58 +09:00 committed by Ingo Molnar
parent 6a5022a56a
commit be8f274323
5 changed files with 17 additions and 58 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
arch/x86/kernel/entry_32.S
View File

@ -314,10 +314,6 @@ ENTRY(ret_from_kernel_thread)
CFI_ENDPROC
ENDPROC(ret_from_kernel_thread)
/*
* Interrupt exit functions should be protected against kprobes
*/
.pushsection .kprobes.text, "ax"
/*
* Return to user mode is not as complex as all this looks,
* but we want the default path for a system call return to
@ -372,10 +368,6 @@ need_resched:
END(resume_kernel)
#endif
CFI_ENDPROC
/*
* End of kprobes section
*/
.popsection
/* SYSENTER_RETURN points to after the "sysenter" instruction in
the vsyscall page. See vsyscall-sysentry.S, which defines the symbol. */
@ -495,10 +487,6 @@ sysexit_audit:
PTGS_TO_GS_EX
ENDPROC(ia32_sysenter_target)
/*
* syscall stub including irq exit should be protected against kprobes
*/
.pushsection .kprobes.text, "ax"
# system call handler stub
ENTRY(system_call)
RING0_INT_FRAME # can't unwind into user space anyway
@ -691,10 +679,6 @@ syscall_badsys:
jmp resume_userspace
END(syscall_badsys)
CFI_ENDPROC
/*
* End of kprobes section
*/
.popsection
.macro FIXUP_ESPFIX_STACK
/*
@ -781,10 +765,6 @@ common_interrupt:
ENDPROC(common_interrupt)
CFI_ENDPROC
/*
* Irq entries should be protected against kprobes
*/
.pushsection .kprobes.text, "ax"
#define BUILD_INTERRUPT3(name, nr, fn) \
ENTRY(name) \
RING0_INT_FRAME; \
@ -961,10 +941,6 @@ ENTRY(spurious_interrupt_bug)
jmp error_code
CFI_ENDPROC
END(spurious_interrupt_bug)
/*
* End of kprobes section
*/
.popsection
#ifdef CONFIG_XEN
/* Xen doesn't set %esp to be precisely what the normal sysenter
@ -1239,11 +1215,6 @@ return_to_handler:
jmp *%ecx
#endif
/*
* Some functions should be protected against kprobes
*/
.pushsection .kprobes.text, "ax"
#ifdef CONFIG_TRACING
ENTRY(trace_page_fault)
RING0_EC_FRAME
@ -1453,7 +1424,3 @@ ENTRY(async_page_fault)
END(async_page_fault)
#endif
/*
* End of kprobes section
*/
.popsection

20
arch/x86/kernel/entry_64.S
View File

@ -487,8 +487,6 @@ ENDPROC(native_usergs_sysret64)
TRACE_IRQS_OFF
.endm
/* save complete stack frame */
.pushsection .kprobes.text, "ax"
ENTRY(save_paranoid)
XCPT_FRAME 1 RDI+8
cld
@ -517,7 +515,6 @@ ENTRY(save_paranoid)
1: ret
CFI_ENDPROC
END(save_paranoid)
.popsection
/*
* A newly forked process directly context switches into this address.
@ -975,10 +972,6 @@ END(interrupt)
call \func
.endm
/*
* Interrupt entry/exit should be protected against kprobes
*/
.pushsection .kprobes.text, "ax"
/*
* The interrupt stubs push (~vector+0x80) onto the stack and
* then jump to common_interrupt.
@ -1113,10 +1106,6 @@ ENTRY(retint_kernel)
CFI_ENDPROC
END(common_interrupt)
/*
* End of kprobes section
*/
.popsection
/*
* APIC interrupts.
@ -1477,11 +1466,6 @@ apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \
hyperv_callback_vector hyperv_vector_handler
#endif /* CONFIG_HYPERV */
/*
* Some functions should be protected against kprobes
*/
.pushsection .kprobes.text, "ax"
paranoidzeroentry_ist debug do_debug DEBUG_STACK
paranoidzeroentry_ist int3 do_int3 DEBUG_STACK
paranoiderrorentry stack_segment do_stack_segment
@ -1898,7 +1882,3 @@ ENTRY(ignore_sysret)
CFI_ENDPROC
END(ignore_sysret)
/*
* End of kprobes section
*/
.popsection

8
arch/x86/kernel/kprobes/core.c
View File

@ -1065,6 +1065,14 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
return 0;
}
bool arch_within_kprobe_blacklist(unsigned long addr)
{
return (addr >= (unsigned long)__kprobes_text_start &&
addr < (unsigned long)__kprobes_text_end) ||
(addr >= (unsigned long)__entry_text_start &&
addr < (unsigned long)__entry_text_end);
}
int __init arch_init_kprobes(void)
{
return 0;

1
include/linux/kprobes.h
View File

@ -265,6 +265,7 @@ extern void arch_disarm_kprobe(struct kprobe *p);
extern int arch_init_kprobes(void);
extern void show_registers(struct pt_regs *regs);
extern void kprobes_inc_nmissed_count(struct kprobe *p);
extern bool arch_within_kprobe_blacklist(unsigned long addr);
struct kprobe_insn_cache {
struct mutex mutex;

13
kernel/kprobes.c
View File

@ -96,9 +96,6 @@ static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
static struct kprobe_blackpoint kprobe_blacklist[] = {
{"preempt_schedule",},
{"native_get_debugreg",},
{"irq_entries_start",},
{"common_interrupt",},
{"mcount",}, /* mcount can be called from everywhere */
{NULL} /* Terminator */
};
@ -1324,12 +1321,18 @@ static int __kprobes register_aggr_kprobe(struct kprobe *orig_p,
return ret;
}
bool __weak arch_within_kprobe_blacklist(unsigned long addr)
{
/* The __kprobes marked functions and entry code must not be probed */
return addr >= (unsigned long)__kprobes_text_start &&
addr < (unsigned long)__kprobes_text_end;
}
static int __kprobes in_kprobes_functions(unsigned long addr)
{
struct kprobe_blackpoint *kb;
if (addr >= (unsigned long)__kprobes_text_start &&
addr < (unsigned long)__kprobes_text_end)
if (arch_within_kprobe_blacklist(addr))
return -EINVAL;
/*
* If there exists a kprobe_blacklist, verify and