From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 14 Dec 2017 12:27:29 +0100 Subject: [PATCH] arch, mm: Allow arch_dup_mmap() to fail MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit CVE-2017-5754 In order to sanitize the LDT initialization on x86 arch_dup_mmap() must be allowed to fail. Fix up all instances. Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Cc: Andy Lutomirski Cc: Andy Lutomirsky Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Dave Hansen Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Will Deacon Cc: aliguori@amazon.com Cc: dan.j.williams@intel.com Cc: hughd@google.com Cc: keescook@google.com Cc: kirill.shutemov@linux.intel.com Cc: linux-mm@kvack.org Signed-off-by: Ingo Molnar (cherry picked from commit c10e83f598d08046dd1ebc8360d4bb12d802d51b) Signed-off-by: Andy Whitcroft Signed-off-by: Kleber Sacilotto de Souza (cherry picked from commit b812abb61437eda1f5718a95085d67902f813f2f) Signed-off-by: Fabian Grünbichler --- arch/powerpc/include/asm/mmu_context.h | 5 +++-- arch/um/include/asm/mmu_context.h | 3 ++- arch/unicore32/include/asm/mmu_context.h | 5 +++-- arch/x86/include/asm/mmu_context.h | 4 ++-- include/asm-generic/mm_hooks.h | 5 +++-- kernel/fork.c | 3 +-- 6 files changed, 14 insertions(+), 11 deletions(-) diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index 35bec1c5bd5a..60afcc94e673 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -185,9 +185,10 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, #endif } -static inline void arch_dup_mmap(struct mm_struct *oldmm, - struct mm_struct *mm) +static inline int arch_dup_mmap(struct mm_struct *oldmm, + struct mm_struct *mm) { + return 0; } static inline void arch_exit_mmap(struct mm_struct *mm) diff --git a/arch/um/include/asm/mmu_context.h b/arch/um/include/asm/mmu_context.h index b668e351fd6c..fca34b2177e2 100644 --- a/arch/um/include/asm/mmu_context.h +++ b/arch/um/include/asm/mmu_context.h @@ -15,9 +15,10 @@ extern void uml_setup_stubs(struct mm_struct *mm); /* * Needed since we do not use the asm-generic/mm_hooks.h: */ -static inline void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) +static inline int arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) { uml_setup_stubs(mm); + return 0; } extern void arch_exit_mmap(struct mm_struct *mm); static inline void arch_unmap(struct mm_struct *mm, diff --git a/arch/unicore32/include/asm/mmu_context.h b/arch/unicore32/include/asm/mmu_context.h index 59b06b48f27d..5c205a9cb5a6 100644 --- a/arch/unicore32/include/asm/mmu_context.h +++ b/arch/unicore32/include/asm/mmu_context.h @@ -81,9 +81,10 @@ do { \ } \ } while (0) -static inline void arch_dup_mmap(struct mm_struct *oldmm, - struct mm_struct *mm) +static inline int arch_dup_mmap(struct mm_struct *oldmm, + struct mm_struct *mm) { + return 0; } static inline void arch_unmap(struct mm_struct *mm, diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index efc530642f7d..9be54d9c04c4 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -175,10 +175,10 @@ do { \ } while (0) #endif -static inline void arch_dup_mmap(struct mm_struct *oldmm, - struct mm_struct *mm) +static inline int arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) { paravirt_arch_dup_mmap(oldmm, mm); + return 0; } static inline void arch_exit_mmap(struct mm_struct *mm) diff --git a/include/asm-generic/mm_hooks.h b/include/asm-generic/mm_hooks.h index 41e5b6784b97..7a2980f4e3e6 100644 --- a/include/asm-generic/mm_hooks.h +++ b/include/asm-generic/mm_hooks.h @@ -6,9 +6,10 @@ #ifndef _ASM_GENERIC_MM_HOOKS_H #define _ASM_GENERIC_MM_HOOKS_H -static inline void arch_dup_mmap(struct mm_struct *oldmm, - struct mm_struct *mm) +static inline int arch_dup_mmap(struct mm_struct *oldmm, + struct mm_struct *mm) { + return 0; } static inline void arch_exit_mmap(struct mm_struct *mm) diff --git a/kernel/fork.c b/kernel/fork.c index 8efc6b4466e3..1d907772b9d2 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -712,8 +712,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, goto out; } /* a new mm has just been created */ - arch_dup_mmap(oldmm, mm); - retval = 0; + retval = arch_dup_mmap(oldmm, mm); out: up_write(&mm->mmap_sem); flush_tlb_mm(oldmm); -- 2.14.2