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Message-ID: <836f75710daef12dfea55f8fb6055d7fdaf716e3.1708078577.git.christophe.leroy@csgroup.eu>
Date: Fri, 16 Feb 2024 11:16:26 +0100
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Michael Ellerman <mpe@...erman.id.au>,
Nicholas Piggin <npiggin@...il.com>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>,
linux-kernel@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH] 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: Christophe Leroy <christophe.leroy@...roup.eu>
---
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 | 39 ++++++++++++++++++++++++----------
5 files changed, 65 insertions(+), 32 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 72341b9fb552..6107e4944509 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 5c02fd08d61e..e94919853ca3 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -130,32 +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();
- ptdump_check_wx();
- 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
@@ -165,7 +174,15 @@ 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);
// mark_initmem_nx() should have already run by now
ptdump_check_wx();
--
2.43.0
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