diff options
Diffstat (limited to 'meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2023-1582.patch')
| -rw-r--r-- | meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2023-1582.patch | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2023-1582.patch b/meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2023-1582.patch new file mode 100644 index 000000000..c38b93c78 --- /dev/null +++ b/meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2023-1582.patch @@ -0,0 +1,228 @@ +From 24d7275ce2791829953ed4e72f68277ceb2571c6 Mon Sep 17 00:00:00 2001 +From: Yang Shi <shy828301@gmail.com> +Date: Fri, 11 Feb 2022 16:32:26 -0800 +Subject: [PATCH] fs/proc: task_mmu.c: don't read mapcount for migration entry + +The syzbot reported the below BUG: + + kernel BUG at include/linux/page-flags.h:785! + invalid opcode: 0000 [#1] PREEMPT SMP KASAN + CPU: 1 PID: 4392 Comm: syz-executor560 Not tainted 5.16.0-rc6-syzkaller #0 + Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 + RIP: 0010:PageDoubleMap include/linux/page-flags.h:785 [inline] + RIP: 0010:__page_mapcount+0x2d2/0x350 mm/util.c:744 + Call Trace: + page_mapcount include/linux/mm.h:837 [inline] + smaps_account+0x470/0xb10 fs/proc/task_mmu.c:466 + smaps_pte_entry fs/proc/task_mmu.c:538 [inline] + smaps_pte_range+0x611/0x1250 fs/proc/task_mmu.c:601 + walk_pmd_range mm/pagewalk.c:128 [inline] + walk_pud_range mm/pagewalk.c:205 [inline] + walk_p4d_range mm/pagewalk.c:240 [inline] + walk_pgd_range mm/pagewalk.c:277 [inline] + __walk_page_range+0xe23/0x1ea0 mm/pagewalk.c:379 + walk_page_vma+0x277/0x350 mm/pagewalk.c:530 + smap_gather_stats.part.0+0x148/0x260 fs/proc/task_mmu.c:768 + smap_gather_stats fs/proc/task_mmu.c:741 [inline] + show_smap+0xc6/0x440 fs/proc/task_mmu.c:822 + seq_read_iter+0xbb0/0x1240 fs/seq_file.c:272 + seq_read+0x3e0/0x5b0 fs/seq_file.c:162 + vfs_read+0x1b5/0x600 fs/read_write.c:479 + ksys_read+0x12d/0x250 fs/read_write.c:619 + do_syscall_x64 arch/x86/entry/common.c:50 [inline] + do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 + entry_SYSCALL_64_after_hwframe+0x44/0xae + +The reproducer was trying to read /proc/$PID/smaps when calling +MADV_FREE at the mean time. MADV_FREE may split THPs if it is called +for partial THP. It may trigger the below race: + + CPU A CPU B + ----- ----- + smaps walk: MADV_FREE: + page_mapcount() + PageCompound() + split_huge_page() + page = compound_head(page) + PageDoubleMap(page) + +When calling PageDoubleMap() this page is not a tail page of THP anymore +so the BUG is triggered. + +This could be fixed by elevated refcount of the page before calling +mapcount, but that would prevent it from counting migration entries, and +it seems overkilling because the race just could happen when PMD is +split so all PTE entries of tail pages are actually migration entries, +and smaps_account() does treat migration entries as mapcount == 1 as +Kirill pointed out. + +Add a new parameter for smaps_account() to tell this entry is migration +entry then skip calling page_mapcount(). Don't skip getting mapcount +for device private entries since they do track references with mapcount. + +Pagemap also has the similar issue although it was not reported. Fixed +it as well. + +[shy828301@gmail.com: v4] + Link: https://lkml.kernel.org/r/20220203182641.824731-1-shy828301@gmail.com +[nathan@kernel.org: avoid unused variable warning in pagemap_pmd_range()] + Link: https://lkml.kernel.org/r/20220207171049.1102239-1-nathan@kernel.org +Link: https://lkml.kernel.org/r/20220120202805.3369-1-shy828301@gmail.com +Fixes: e9b61f19858a ("thp: reintroduce split_huge_page()") +Signed-off-by: Yang Shi <shy828301@gmail.com> +Signed-off-by: Nathan Chancellor <nathan@kernel.org> +Reported-by: syzbot+1f52b3a18d5633fa7f82@syzkaller.appspotmail.com +Acked-by: David Hildenbrand <david@redhat.com> +Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> +Cc: Jann Horn <jannh@google.com> +Cc: Matthew Wilcox <willy@infradead.org> +Cc: Alexey Dobriyan <adobriyan@gmail.com> +Cc: <stable@vger.kernel.org> +Signed-off-by: Andrew Morton <akpm@linux-foundation.org> +Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> +--- + fs/proc/task_mmu.c | 40 +++++++++++++++++++++++++++++++--------- + 1 file changed, 31 insertions(+), 9 deletions(-) + +diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c +index cf25be3e0321..3e68cc9e816c 100644 +--- a/fs/proc/task_mmu.c ++++ b/fs/proc/task_mmu.c +@@ -430,7 +430,8 @@ static void smaps_page_accumulate(struct mem_size_stats *mss, + } + + static void smaps_account(struct mem_size_stats *mss, struct page *page, +- bool compound, bool young, bool dirty, bool locked) ++ bool compound, bool young, bool dirty, bool locked, ++ bool migration) + { + int i, nr = compound ? compound_nr(page) : 1; + unsigned long size = nr * PAGE_SIZE; +@@ -457,8 +458,15 @@ static void smaps_account(struct mem_size_stats *mss, struct page *page, + * page_count(page) == 1 guarantees the page is mapped exactly once. + * If any subpage of the compound page mapped with PTE it would elevate + * page_count(). ++ * ++ * The page_mapcount() is called to get a snapshot of the mapcount. ++ * Without holding the page lock this snapshot can be slightly wrong as ++ * we cannot always read the mapcount atomically. It is not safe to ++ * call page_mapcount() even with PTL held if the page is not mapped, ++ * especially for migration entries. Treat regular migration entries ++ * as mapcount == 1. + */ +- if (page_count(page) == 1) { ++ if ((page_count(page) == 1) || migration) { + smaps_page_accumulate(mss, page, size, size << PSS_SHIFT, dirty, + locked, true); + return; +@@ -495,6 +503,7 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr, + struct vm_area_struct *vma = walk->vma; + bool locked = !!(vma->vm_flags & VM_LOCKED); + struct page *page = NULL; ++ bool migration = false; + + if (pte_present(*pte)) { + page = vm_normal_page(vma, addr, *pte); +@@ -514,8 +523,11 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr, + } else { + mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT; + } +- } else if (is_pfn_swap_entry(swpent)) ++ } else if (is_pfn_swap_entry(swpent)){ ++ if (is_migration_entry(swpent)) ++ migration = true; + page = pfn_swap_entry_to_page(swpent); ++ } + } else if (unlikely(IS_ENABLED(CONFIG_SHMEM) && mss->check_shmem_swap + && pte_none(*pte))) { + page = xa_load(&vma->vm_file->f_mapping->i_pages, +@@ -528,7 +540,8 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr, + if (!page) + return; + +- smaps_account(mss, page, false, pte_young(*pte), pte_dirty(*pte), locked); ++ smaps_account(mss, page, false, pte_young(*pte), pte_dirty(*pte), ++ locked, migration); + } + + #ifdef CONFIG_TRANSPARENT_HUGEPAGE +@@ -539,6 +552,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, + struct vm_area_struct *vma = walk->vma; + bool locked = !!(vma->vm_flags & VM_LOCKED); + struct page *page = NULL; ++ bool migration = false; + + if (pmd_present(*pmd)) { + /* FOLL_DUMP will return -EFAULT on huge zero page */ +@@ -546,8 +560,10 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, + } else if (unlikely(thp_migration_supported() && is_swap_pmd(*pmd))) { + swp_entry_t entry = pmd_to_swp_entry(*pmd); + +- if (is_migration_entry(entry)) ++ if (is_migration_entry(entry)) { ++ migration = true; + page = pfn_swap_entry_to_page(entry); ++ } + } + if (IS_ERR_OR_NULL(page)) + return; +@@ -559,7 +575,9 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, + /* pass */; + else + mss->file_thp += HPAGE_PMD_SIZE; +- smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd), locked); ++ ++ smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd), ++ locked, migration); + } + #else + static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, +@@ -1363,6 +1381,7 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm, + { + u64 frame = 0, flags = 0; + struct page *page = NULL; ++ bool migration = false; + + if (pte_present(pte)) { + if (pm->show_pfn) +@@ -1384,13 +1403,14 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm, + frame = swp_type(entry) | + (swp_offset(entry) << MAX_SWAPFILES_SHIFT); + flags |= PM_SWAP; ++ migration = is_migration_entry(entry); + if (is_pfn_swap_entry(entry)) + page = pfn_swap_entry_to_page(entry); + } + + if (page && !PageAnon(page)) + flags |= PM_FILE; +- if (page && page_mapcount(page) == 1) ++ if (page && !migration && page_mapcount(page) == 1) + flags |= PM_MMAP_EXCLUSIVE; + if (vma->vm_flags & VM_SOFTDIRTY) + flags |= PM_SOFT_DIRTY; +@@ -1406,8 +1426,9 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end, + spinlock_t *ptl; + pte_t *pte, *orig_pte; + int err = 0; +- + #ifdef CONFIG_TRANSPARENT_HUGEPAGE ++ bool migration = false; ++ + ptl = pmd_trans_huge_lock(pmdp, vma); + if (ptl) { + u64 flags = 0, frame = 0; +@@ -1446,11 +1467,12 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end, + if (pmd_swp_uffd_wp(pmd)) + flags |= PM_UFFD_WP; + VM_BUG_ON(!is_pmd_migration_entry(pmd)); ++ migration = is_migration_entry(entry); + page = pfn_swap_entry_to_page(entry); + } + #endif + +- if (page && page_mapcount(page) == 1) ++ if (page && !migration && page_mapcount(page) == 1) + flags |= PM_MMAP_EXCLUSIVE; + + for (; addr != end; addr += PAGE_SIZE) { |