Commit 111e7b15 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86/ioperm: Extend IOPL config to control ioperm() as well 



If iopl() is disabled, then providing ioperm() does not make much sense.

Rename the config option and disable/enable both syscalls with it. Guard
the code with #ifdefs where appropriate.

Suggested-by: default avatarAndy Lutomirski <luto@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent a24ca997

arch/x86/Kconfig

+5 −2
Original line number Diff line number Diff line
@@ -1254,10 +1254,13 @@ config X86_VSYSCALL_EMULATION 
	 Disabling this option saves about 7K of kernel size and

	 possibly 4K of additional runtime pagetable memory.



config X86_IOPL_EMULATION

	bool "IOPL Emulation"

config X86_IOPL_IOPERM

	bool "IOPERM and IOPL Emulation"

	default y

	---help---

	  This enables the ioperm() and iopl() syscalls which are necessary

	  for legacy applications.



	  Legacy IOPL support is an overbroad mechanism which allows user

	  space aside of accessing all 65536 I/O ports also to disable

	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO

arch/x86/include/asm/io_bitmap.h

+6 −0
Original line number Diff line number Diff line
@@ -15,9 +15,15 @@ struct io_bitmap { 


struct task_struct;



#ifdef CONFIG_X86_IOPL_IOPERM

void io_bitmap_share(struct task_struct *tsk);

void io_bitmap_exit(void);



void tss_update_io_bitmap(void);

#else

static inline void io_bitmap_share(struct task_struct *tsk) { }

static inline void io_bitmap_exit(void) { }

static inline void tss_update_io_bitmap(void) { }

#endif



#endif

arch/x86/include/asm/processor.h

+8 −1
Original line number Diff line number Diff line
@@ -340,6 +340,7 @@ struct x86_hw_tss { 
	(offsetof(struct tss_struct, io_bitmap.mapall) -	\

	 offsetof(struct tss_struct, x86_tss))



#ifdef CONFIG_X86_IOPL_IOPERM

/*

 * sizeof(unsigned long) coming from an extra "long" at the end of the

 * iobitmap. The limit is inclusive, i.e. the last valid byte.
@@ -347,6 +348,10 @@ struct x86_hw_tss { 
# define __KERNEL_TSS_LIMIT	\

	(IO_BITMAP_OFFSET_VALID_ALL + IO_BITMAP_BYTES + \

	 sizeof(unsigned long) - 1)

#else

# define __KERNEL_TSS_LIMIT	\

	(offsetof(struct tss_struct, x86_tss) + sizeof(struct x86_hw_tss) - 1)

#endif



/* Base offset outside of TSS_LIMIT so unpriviledged IO causes #GP */

#define IO_BITMAP_OFFSET_INVALID	(__KERNEL_TSS_LIMIT + 1)
@@ -398,7 +403,9 @@ struct tss_struct { 
	 */

	struct x86_hw_tss	x86_tss;



#ifdef CONFIG_X86_IOPL_IOPERM

	struct x86_io_bitmap	io_bitmap;

#endif

} __aligned(PAGE_SIZE);



DECLARE_PER_CPU_PAGE_ALIGNED(struct tss_struct, cpu_tss_rw);

arch/x86/include/asm/thread_info.h

+6 −1
Original line number Diff line number Diff line
@@ -156,8 +156,13 @@ struct thread_info { 
# define _TIF_WORK_CTXSW	(_TIF_WORK_CTXSW_BASE)

#endif



#ifdef CONFIG_X86_IOPL_IOPERM

# define _TIF_WORK_CTXSW_PREV	(_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY | \

				 _TIF_IO_BITMAP)

#else

# define _TIF_WORK_CTXSW_PREV	(_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY)

#endif



#define _TIF_WORK_CTXSW_NEXT	(_TIF_WORK_CTXSW)



#define STACK_WARN		(THREAD_SIZE/8)

arch/x86/kernel/cpu/common.c

+17 −9
Original line number Diff line number Diff line
@@ -1804,6 +1804,22 @@ static inline void gdt_setup_doublefault_tss(int cpu) 
}

#endif /* !CONFIG_X86_64 */



static inline void tss_setup_io_bitmap(struct tss_struct *tss)

{

	tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_INVALID;



#ifdef CONFIG_X86_IOPL_IOPERM

	tss->io_bitmap.prev_max = 0;

	tss->io_bitmap.prev_sequence = 0;

	memset(tss->io_bitmap.bitmap, 0xff, sizeof(tss->io_bitmap.bitmap));

	/*

	 * Invalidate the extra array entry past the end of the all

	 * permission bitmap as required by the hardware.

	 */

	tss->io_bitmap.mapall[IO_BITMAP_LONGS] = ~0UL;

#endif

}



/*

 * cpu_init() initializes state that is per-CPU. Some data is already

 * initialized (naturally) in the bootstrap process, such as the GDT
@@ -1860,15 +1876,7 @@ void cpu_init(void) 


	/* Initialize the TSS. */

	tss_setup_ist(tss);

	tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_INVALID;

	tss->io_bitmap.prev_max = 0;

	tss->io_bitmap.prev_sequence = 0;

	memset(tss->io_bitmap.bitmap, 0xff, sizeof(tss->io_bitmap.bitmap));

	/*

	 * Invalidate the extra array entry past the end of the all

	 * permission bitmap as required by the hardware.

	 */

	tss->io_bitmap.mapall[IO_BITMAP_LONGS] = ~0UL;

	tss_setup_io_bitmap(tss);

	set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);



	load_TR_desc();

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