From: Alexandre Ghiti alexghiti@rivosinc.com

mainline inclusion from mainline-v6.1-rc8 commit 3f105a742725a1b78766a55169f1d827732e62b8 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYRII CVE: CVE-2022-49004

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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The EFI page table is initially created as a copy of the kernel page table. With VMAP_STACK enabled, kernel stacks are allocated in the vmalloc area: if the stack is allocated in a new PGD (one that was not present at the moment of the efi page table creation or not synced in a previous vmalloc fault), the kernel will take a trap when switching to the efi page table when the vmalloc kernel stack is accessed, resulting in a kernel panic.

Fix that by updating the efi kernel mappings before switching to the efi page table.

Signed-off-by: Alexandre Ghiti alexghiti@rivosinc.com Fixes: b91540d52a08 ("RISC-V: Add EFI runtime services") Tested-by: Emil Renner Berthing emil.renner.berthing@canonical.com Reviewed-by: Atish Patra atishp@rivosinc.com Link: https://lore.kernel.org/r/20221121133303.1782246-1-alexghiti@rivosinc.com Signed-off-by: Palmer Dabbelt palmer@rivosinc.com

Conflicts: arch/riscv/include/asm/pgalloc.h [context is mismatch] Signed-off-by: Chen Ridong chenridong@huawei.com --- arch/riscv/include/asm/efi.h | 6 +++++- arch/riscv/include/asm/pgalloc.h | 11 ++++++++--- 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/include/asm/efi.h b/arch/riscv/include/asm/efi.h index 3a6bb2268f11..5b155f076614 100644 --- a/arch/riscv/include/asm/efi.h +++ b/arch/riscv/include/asm/efi.h @@ -10,6 +10,7 @@ #include <asm/mmu_context.h> #include <asm/ptrace.h> #include <asm/tlbflush.h> +#include <asm/pgalloc.h>

#ifdef CONFIG_EFI extern void efi_init(void); @@ -20,7 +21,10 @@ extern void efi_init(void); int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md); int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);

-#define arch_efi_call_virt_setup() efi_virtmap_load() +#define arch_efi_call_virt_setup() ({ \ + sync_kernel_mappings(efi_mm.pgd); \ + efi_virtmap_load(); \ + }) #define arch_efi_call_virt_teardown() efi_virtmap_unload()

#define ARCH_EFI_IRQ_FLAGS_MASK (SR_IE | SR_SPIE) diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h index 23b1544e0ca5..7b6a8aab9abe 100644 --- a/arch/riscv/include/asm/pgalloc.h +++ b/arch/riscv/include/asm/pgalloc.h @@ -40,6 +40,13 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)

#define pmd_pgtable(pmd) pmd_page(pmd)

+static inline void sync_kernel_mappings(pgd_t *pgd) +{ + memcpy(pgd + USER_PTRS_PER_PGD, + init_mm.pgd + USER_PTRS_PER_PGD, + (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); +} + static inline pgd_t *pgd_alloc(struct mm_struct *mm) { pgd_t *pgd; @@ -48,9 +55,7 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm) if (likely(pgd != NULL)) { memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t)); /* Copy kernel mappings */ - memcpy(pgd + USER_PTRS_PER_PGD, - init_mm.pgd + USER_PTRS_PER_PGD, - (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); + sync_kernel_mappings(pgd); } return pgd; }