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From 4f4c549feb4ecca95ae9abb88887b941d196f83a Mon Sep 17 00:00:00 2001 |
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From: Catalin Marinas <catalin.marinas@arm.com> |
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Date: Thu, 22 Dec 2022 18:12:51 +0000 |
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Subject: arm64: mte: Avoid the racy walk of the vma list during core dump |
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|
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From: Catalin Marinas <catalin.marinas@arm.com> |
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|
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commit 4f4c549feb4ecca95ae9abb88887b941d196f83a upstream. |
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|
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The MTE coredump code in arch/arm64/kernel/elfcore.c iterates over the |
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vma list without the mmap_lock held. This can race with another process |
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or userfaultfd concurrently modifying the vma list. Change the |
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for_each_mte_vma macro and its callers to instead use the vma snapshot |
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taken by dump_vma_snapshot() and stored in the cprm object. |
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|
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Fixes: 6dd8b1a0b6cb ("arm64: mte: Dump the MTE tags in the core file") |
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Cc: <stable@vger.kernel.org> # 5.18.x |
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Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> |
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Reported-by: Seth Jenkins <sethjenkins@google.com> |
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Suggested-by: Seth Jenkins <sethjenkins@google.com> |
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Cc: Will Deacon <will@kernel.org> |
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Link: https://lore.kernel.org/r/20221222181251.1345752-4-catalin.marinas@arm.com |
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Signed-off-by: Will Deacon <will@kernel.org> |
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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--- |
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arch/arm64/kernel/elfcore.c | 56 ++++++++++++++++++++------------------------ |
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1 file changed, 26 insertions(+), 30 deletions(-) |
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|
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--- a/arch/arm64/kernel/elfcore.c |
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+++ b/arch/arm64/kernel/elfcore.c |
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@@ -8,28 +8,27 @@ |
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#include <asm/cpufeature.h> |
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#include <asm/mte.h> |
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|
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-#define for_each_mte_vma(vmi, vma) \ |
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+#define for_each_mte_vma(cprm, i, m) \ |
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if (system_supports_mte()) \ |
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- for_each_vma(vmi, vma) \ |
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- if (vma->vm_flags & VM_MTE) |
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+ for (i = 0, m = cprm->vma_meta; \ |
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+ i < cprm->vma_count; \ |
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+ i++, m = cprm->vma_meta + i) \ |
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+ if (m->flags & VM_MTE) |
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|
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-static unsigned long mte_vma_tag_dump_size(struct vm_area_struct *vma) |
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+static unsigned long mte_vma_tag_dump_size(struct core_vma_metadata *m) |
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{ |
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- if (vma->vm_flags & VM_DONTDUMP) |
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- return 0; |
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- |
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- return vma_pages(vma) * MTE_PAGE_TAG_STORAGE; |
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+ return (m->dump_size >> PAGE_SHIFT) * MTE_PAGE_TAG_STORAGE; |
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} |
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|
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/* Derived from dump_user_range(); start/end must be page-aligned */ |
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static int mte_dump_tag_range(struct coredump_params *cprm, |
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- unsigned long start, unsigned long end) |
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+ unsigned long start, unsigned long len) |
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{ |
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int ret = 1; |
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unsigned long addr; |
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void *tags = NULL; |
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|
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- for (addr = start; addr < end; addr += PAGE_SIZE) { |
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+ for (addr = start; addr < start + len; addr += PAGE_SIZE) { |
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struct page *page = get_dump_page(addr); |
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|
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/* |
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@@ -78,11 +77,11 @@ static int mte_dump_tag_range(struct cor |
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|
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Elf_Half elf_core_extra_phdrs(void) |
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{ |
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- struct vm_area_struct *vma; |
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+ int i; |
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+ struct core_vma_metadata *m; |
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int vma_count = 0; |
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- VMA_ITERATOR(vmi, current->mm, 0); |
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|
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- for_each_mte_vma(vmi, vma) |
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+ for_each_mte_vma(cprm, i, m) |
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vma_count++; |
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|
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return vma_count; |
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@@ -90,18 +89,18 @@ Elf_Half elf_core_extra_phdrs(void) |
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|
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int elf_core_write_extra_phdrs(struct coredump_params *cprm, loff_t offset) |
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{ |
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- struct vm_area_struct *vma; |
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- VMA_ITERATOR(vmi, current->mm, 0); |
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+ int i; |
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+ struct core_vma_metadata *m; |
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|
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- for_each_mte_vma(vmi, vma) { |
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+ for_each_mte_vma(cprm, i, m) { |
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struct elf_phdr phdr; |
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|
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phdr.p_type = PT_AARCH64_MEMTAG_MTE; |
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phdr.p_offset = offset; |
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- phdr.p_vaddr = vma->vm_start; |
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+ phdr.p_vaddr = m->start; |
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phdr.p_paddr = 0; |
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- phdr.p_filesz = mte_vma_tag_dump_size(vma); |
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- phdr.p_memsz = vma->vm_end - vma->vm_start; |
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+ phdr.p_filesz = mte_vma_tag_dump_size(m); |
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+ phdr.p_memsz = m->end - m->start; |
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offset += phdr.p_filesz; |
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phdr.p_flags = 0; |
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phdr.p_align = 0; |
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@@ -115,26 +114,23 @@ int elf_core_write_extra_phdrs(struct co |
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|
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size_t elf_core_extra_data_size(void) |
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{ |
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- struct vm_area_struct *vma; |
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+ int i; |
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+ struct core_vma_metadata *m; |
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size_t data_size = 0; |
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- VMA_ITERATOR(vmi, current->mm, 0); |
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|
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- for_each_mte_vma(vmi, vma) |
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- data_size += mte_vma_tag_dump_size(vma); |
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+ for_each_mte_vma(cprm, i, m) |
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+ data_size += mte_vma_tag_dump_size(m); |
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|
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return data_size; |
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} |
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|
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int elf_core_write_extra_data(struct coredump_params *cprm) |
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{ |
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- struct vm_area_struct *vma; |
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- VMA_ITERATOR(vmi, current->mm, 0); |
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- |
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- for_each_mte_vma(vmi, vma) { |
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- if (vma->vm_flags & VM_DONTDUMP) |
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- continue; |
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+ int i; |
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+ struct core_vma_metadata *m; |
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|
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- if (!mte_dump_tag_range(cprm, vma->vm_start, vma->vm_end)) |
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+ for_each_mte_vma(cprm, i, m) { |
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+ if (!mte_dump_tag_range(cprm, m->start, m->dump_size)) |
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return 0; |
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} |
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