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: Christophe Leroy <christophe.le...@csgroup.eu> Signed-off-by: Michael Ellerman <m...@ellerman.id.au> Link: https://msgid.link/836f75710daef12dfea55f8fb6055d7fdaf716e3.1708078577.git.christophe.le...@csgroup.eu --- v2: Rebased on top of 6388eaa7f116 ("Automatic merge of 'master' into merge (2024-03-16 10:18)") --- arch/powerpc/mm/book3s32/mmu.c | 7 +++++-- arch/powerpc/mm/mmu_decl.h | 8 +++---- arch/powerpc/mm/nohash/8xx.c | 33 ++++++++++++++++++----------- arch/powerpc/mm/nohash/e500.c | 10 ++++++--- arch/powerpc/mm/pgtable_32.c | 38 +++++++++++++++++++++++++--------- 5 files changed, 65 insertions(+), 31 deletions(-) diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c index 5445587bfe84..100f999871bc 100644 --- a/arch/powerpc/mm/book3s32/mmu.c +++ b/arch/powerpc/mm/book3s32/mmu.c @@ -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; } /* diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h index 8e84bc214d13..6949c2c937e7 100644 --- a/arch/powerpc/mm/mmu_decl.h +++ b/arch/powerpc/mm/mmu_decl.h @@ -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 diff --git a/arch/powerpc/mm/nohash/8xx.c b/arch/powerpc/mm/nohash/8xx.c index 6be6421086ed..43d4842bb1c7 100644 --- a/arch/powerpc/mm/nohash/8xx.c +++ b/arch/powerpc/mm/nohash/8xx.c @@ -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, - pgprot_t prot, bool new) +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 diff --git a/arch/powerpc/mm/nohash/e500.c b/arch/powerpc/mm/nohash/e500.c index 921c3521ec11..266fb22131fc 100644 --- a/arch/powerpc/mm/nohash/e500.c +++ b/arch/powerpc/mm/nohash/e500.c @@ -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, diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c index face94977cb2..cfd622ebf774 100644 --- a/arch/powerpc/mm/pgtable_32.c +++ b/arch/powerpc/mm/pgtable_32.c @@ -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 -- 2.43.0
