Commit 78cb0945 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc: Handle error in mark_rodata_ro() and mark_initmem_nx() 

mark_rodata_ro() and mark_initmem_nx() use functions that can
fail like set_memory_nx() and set_memory_ro(), leading to a not
protected kernel.

In case of failure, panic.

Link: https://github.com/KSPP/linux/issues/7


Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/b16329611deb89e1af505d43f0e2a91310584d26.1710587887.git.christophe.leroy@csgroup.eu
parent 66a27aba

arch/powerpc/mm/book3s32/mmu.c

+5 −2
Original line number Diff line number Diff line
@@ -193,7 +193,7 @@ static bool is_module_segment(unsigned long addr) 
	return true;

}



void mmu_mark_initmem_nx(void)

int mmu_mark_initmem_nx(void)

{

	int nb = mmu_has_feature(MMU_FTR_USE_HIGH_BATS) ? 8 : 4;

	int i;
@@ -230,9 +230,10 @@ void mmu_mark_initmem_nx(void) 


		mtsr(mfsr(i << 28) | 0x10000000, i << 28);

	}

	return 0;

}



void mmu_mark_rodata_ro(void)

int mmu_mark_rodata_ro(void)

{

	int nb = mmu_has_feature(MMU_FTR_USE_HIGH_BATS) ? 8 : 4;

	int i;
@@ -245,6 +246,8 @@ void mmu_mark_rodata_ro(void) 
	}



	update_bats();



	return 0;

}



/*

arch/powerpc/mm/mmu_decl.h

+4 −4
Original line number Diff line number Diff line
@@ -160,11 +160,11 @@ static inline unsigned long p_block_mapped(phys_addr_t pa) { return 0; } 
#endif



#if defined(CONFIG_PPC_BOOK3S_32) || defined(CONFIG_PPC_8xx) || defined(CONFIG_PPC_E500)

void mmu_mark_initmem_nx(void);

void mmu_mark_rodata_ro(void);

int mmu_mark_initmem_nx(void);

int mmu_mark_rodata_ro(void);

#else

static inline void mmu_mark_initmem_nx(void) { }

static inline void mmu_mark_rodata_ro(void) { }

static inline int mmu_mark_initmem_nx(void) { return 0; }

static inline int mmu_mark_rodata_ro(void) { return 0; }

#endif



#ifdef CONFIG_PPC_8xx

arch/powerpc/mm/nohash/8xx.c

+21 −12
Original line number Diff line number Diff line
@@ -119,23 +119,26 @@ void __init mmu_mapin_immr(void) 
				    PAGE_KERNEL_NCG, MMU_PAGE_512K, true);

}



static void mmu_mapin_ram_chunk(unsigned long offset, unsigned long top,

static int mmu_mapin_ram_chunk(unsigned long offset, unsigned long top,

			       pgprot_t prot, bool new)

{

	unsigned long v = PAGE_OFFSET + offset;

	unsigned long p = offset;

	int err = 0;



	WARN_ON(!IS_ALIGNED(offset, SZ_512K) || !IS_ALIGNED(top, SZ_512K));



	for (; p < ALIGN(p, SZ_8M) && p < top; p += SZ_512K, v += SZ_512K)

		__early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new);

	for (; p < ALIGN_DOWN(top, SZ_8M) && p < top; p += SZ_8M, v += SZ_8M)

		__early_map_kernel_hugepage(v, p, prot, MMU_PAGE_8M, new);

	for (; p < ALIGN_DOWN(top, SZ_512K) && p < top; p += SZ_512K, v += SZ_512K)

		__early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new);

	for (; p < ALIGN(p, SZ_8M) && p < top && !err; p += SZ_512K, v += SZ_512K)

		err = __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new);

	for (; p < ALIGN_DOWN(top, SZ_8M) && p < top && !err; p += SZ_8M, v += SZ_8M)

		err = __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_8M, new);

	for (; p < ALIGN_DOWN(top, SZ_512K) && p < top && !err; p += SZ_512K, v += SZ_512K)

		err = __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new);



	if (!new)

		flush_tlb_kernel_range(PAGE_OFFSET + v, PAGE_OFFSET + top);



	return err;

}



unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
@@ -166,27 +169,33 @@ unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top) 
	return top;

}



void mmu_mark_initmem_nx(void)

int mmu_mark_initmem_nx(void)

{

	unsigned long etext8 = ALIGN(__pa(_etext), SZ_8M);

	unsigned long sinittext = __pa(_sinittext);

	unsigned long boundary = strict_kernel_rwx_enabled() ? sinittext : etext8;

	unsigned long einittext8 = ALIGN(__pa(_einittext), SZ_8M);

	int err = 0;



	if (!debug_pagealloc_enabled_or_kfence())

		mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL, false);

		err = mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL, false);



	mmu_pin_tlb(block_mapped_ram, false);



	return err;

}



#ifdef CONFIG_STRICT_KERNEL_RWX

void mmu_mark_rodata_ro(void)

int mmu_mark_rodata_ro(void)

{

	unsigned long sinittext = __pa(_sinittext);

	int err;



	mmu_mapin_ram_chunk(0, sinittext, PAGE_KERNEL_ROX, false);

	err = mmu_mapin_ram_chunk(0, sinittext, PAGE_KERNEL_ROX, false);

	if (IS_ENABLED(CONFIG_PIN_TLB_DATA))

		mmu_pin_tlb(block_mapped_ram, true);



	return err;

}

#endif

arch/powerpc/mm/nohash/e500.c

+7 −3
Original line number Diff line number Diff line
@@ -285,19 +285,23 @@ void __init adjust_total_lowmem(void) 
}



#ifdef CONFIG_STRICT_KERNEL_RWX

void mmu_mark_rodata_ro(void)

int mmu_mark_rodata_ro(void)

{

	unsigned long remapped;



	remapped = map_mem_in_cams(__max_low_memory, CONFIG_LOWMEM_CAM_NUM, false, false);



	WARN_ON(__max_low_memory != remapped);

	if (WARN_ON(__max_low_memory != remapped))

		return -EINVAL;



	return 0;

}

#endif



void mmu_mark_initmem_nx(void)

int mmu_mark_initmem_nx(void)

{

	/* Everything is done in mmu_mark_rodata_ro() */

	return 0;

}



void setup_initial_memory_limit(phys_addr_t first_memblock_base,

arch/powerpc/mm/pgtable_32.c

+28 −10
Original line number Diff line number Diff line
@@ -130,31 +130,41 @@ void __init mapin_ram(void) 
	}

}



void mark_initmem_nx(void)

static int __mark_initmem_nx(void)

{

	unsigned long numpages = PFN_UP((unsigned long)_einittext) -

				 PFN_DOWN((unsigned long)_sinittext);

	int err;



	mmu_mark_initmem_nx();

	err = mmu_mark_initmem_nx();



	if (!v_block_mapped((unsigned long)_sinittext)) {

		set_memory_nx((unsigned long)_sinittext, numpages);

		set_memory_rw((unsigned long)_sinittext, numpages);

		err = set_memory_nx((unsigned long)_sinittext, numpages);

		if (err)

			return err;

		err = set_memory_rw((unsigned long)_sinittext, numpages);

	}

	return err;

}



void mark_initmem_nx(void)

{

	int err = __mark_initmem_nx();



	if (err)

		panic("%s() failed, err = %d\n", __func__, err);

}



#ifdef CONFIG_STRICT_KERNEL_RWX

void mark_rodata_ro(void)

static int __mark_rodata_ro(void)

{

	unsigned long numpages;



	if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX) && mmu_has_feature(MMU_FTR_HPTE_TABLE))

		pr_warn("This platform has HASH MMU, STRICT_MODULE_RWX won't work\n");



	if (v_block_mapped((unsigned long)_stext + 1)) {

		mmu_mark_rodata_ro();

		return;

	}

	if (v_block_mapped((unsigned long)_stext + 1))

		return mmu_mark_rodata_ro();



	/*

	 * mark text and rodata as read only. __end_rodata is set by
@@ -164,6 +174,14 @@ void mark_rodata_ro(void) 
	numpages = PFN_UP((unsigned long)__end_rodata) -

		   PFN_DOWN((unsigned long)_stext);



	set_memory_ro((unsigned long)_stext, numpages);

	return set_memory_ro((unsigned long)_stext, numpages);

}



void mark_rodata_ro(void)

{

	int err = __mark_rodata_ro();



	if (err)

		panic("%s() failed, err = %d\n", __func__, err);

}

#endif