From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 088852D047 for ; Wed, 27 Mar 2024 20:11:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711570297; cv=none; b=cBZBdlWAyko7IStr/JiIehgYj0KTn1QFUvCYTT1FaUpOqmRJ4cQZjWyzhfze8LhYuswhc5/duJhdAKScwzw4h0WGls5b0lU07BbRbuCmXidU7Tc6i71fw6uikSs4l0b/55qYLr0NyatTB8QI+Bvc7AMUnyHVJxVp0axyJRWLjh0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711570297; c=relaxed/simple; bh=boKC2oXyUvRA8g7GQCpjQ1fXNaYy+KMxmmah8lrzyNI=; h=Date:To:From:Subject:Message-Id; b=VAWVeENLaLov7trt+78o2FhYAdmHRS1JFCn8yCrC/nWz9K1jgzRKbVOSuBg1MOpcW+WQCNWwcr2HM2DyvgQNGpxG4DadzC/Wq3lCgdUxAi4pnxuad887hex6CT9GILXSBNm7qpjhWn6jGWhbglaW3GDcjPsgaJ5I7VdF/XRtHxY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=lPJfum8Z; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="lPJfum8Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B58D8C433C7; Wed, 27 Mar 2024 20:11:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1711570296; bh=boKC2oXyUvRA8g7GQCpjQ1fXNaYy+KMxmmah8lrzyNI=; h=Date:To:From:Subject:From; b=lPJfum8ZW9UimY3l+0I3OzqYjKMGTQq62W9OZll9GYLW97EnpezYnhkUbzrtNIP/r FA1l79TsrPTZpJ8pDyK16QtYlU9/lg2sDOCAQa0CbqUxmA8B/4fhXiRinA8AKP2TBX Iw4KGk7cOXGdveXHauOajmH3Q7HaW7NZGX/nnSAA= Date: Wed, 27 Mar 2024 13:11:36 -0700 To: mm-commits@vger.kernel.org,tglx@linutronix.de,peterz@infradead.org,npiggin@gmail.com,naveen.n.rao@linux.ibm.com,mpe@ellerman.id.au,mingo@redhat.com,luto@kernel.org,Liam.Howlett@oracle.com,kirill.shutemov@linux.intel.com,keescook@chromium.org,James.Bottomley@HansenPartnership.com,hpa@zytor.com,guoren@kernel.org,deller@gmx.de,debug@rivosinc.com,dave.hansen@linux.intel.com,dan.j.williams@intel.com,christophe.leroy@csgroup.eu,broonie@kernel.org,bp@alien8.de,ast@kernel.org,aneesh.kumar@kernel.org,rick.p.edgecombe@intel.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-use-get_unmapped_area_vmflags.patch added to mm-unstable branch Message-Id: <20240327201136.B58D8C433C7@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm: use get_unmapped_area_vmflags() has been added to the -mm mm-unstable branch. Its filename is mm-use-get_unmapped_area_vmflags.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-use-get_unmapped_area_vmflags.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Rick Edgecombe Subject: mm: use get_unmapped_area_vmflags() Date: Mon, 25 Mar 2024 19:16:47 -0700 When memory is being placed, mmap() will take care to respect the guard gaps of certain types of memory (VM_SHADOWSTACK, VM_GROWSUP and VM_GROWSDOWN). In order to ensure guard gaps between mappings, mmap() needs to consider two things: 1. That the new mapping isn't placed in an any existing mappings guard gaps. 2. That the new mapping isn't placed such that any existing mappings are not in *its* guard gaps. The long standing behavior of mmap() is to ensure 1, but not take any care around 2. So for example, if there is a PAGE_SIZE free area, and a mmap() with a PAGE_SIZE size, and a type that has a guard gap is being placed, mmap() may place the shadow stack in the PAGE_SIZE free area. Then the mapping that is supposed to have a guard gap will not have a gap to the adjacent VMA. Use mm_get_unmapped_area_vmflags() in the do_mmap() so future changes can cause shadow stack mappings to be placed with a guard gap. Also use the THP variant that takes vm_flags, such that THP shadow stack can get the same treatment. Adjust the vm_flags calculation to happen earlier so that the vm_flags can be passed into __get_unmapped_area(). Link: https://lkml.kernel.org/r/20240326021656.202649-6-rick.p.edgecombe@intel.com Signed-off-by: Rick Edgecombe Reviewed-by: Christophe Leroy Cc: Alexei Starovoitov Cc: Andy Lutomirski Cc: Aneesh Kumar K.V Cc: Borislav Petkov (AMD) Cc: Dan Williams Cc: Dave Hansen Cc: Deepak Gupta Cc: Guo Ren Cc: Helge Deller Cc: H. Peter Anvin (Intel) Cc: Ingo Molnar Cc: "James E.J. Bottomley" Cc: Kees Cook Cc: Kirill A. Shutemov Cc: Liam R. Howlett Cc: Mark Brown Cc: Michael Ellerman Cc: Naveen N. Rao Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Andrew Morton --- include/linux/mm.h | 11 ++++++++++- mm/mmap.c | 32 ++++++++++++++++---------------- 2 files changed, 26 insertions(+), 17 deletions(-) --- a/include/linux/mm.h~mm-use-get_unmapped_area_vmflags +++ a/include/linux/mm.h @@ -3412,7 +3412,16 @@ extern int install_special_mapping(struc unsigned long randomize_stack_top(unsigned long stack_top); unsigned long randomize_page(unsigned long start, unsigned long range); -extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); +unsigned long +__get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, + unsigned long pgoff, unsigned long flags, vm_flags_t vm_flags); + +static inline unsigned long +get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, + unsigned long pgoff, unsigned long flags) +{ + return __get_unmapped_area(file, addr, len, pgoff, flags, 0); +} extern unsigned long mmap_region(struct file *file, unsigned long addr, unsigned long len, vm_flags_t vm_flags, unsigned long pgoff, --- a/mm/mmap.c~mm-use-get_unmapped_area_vmflags +++ a/mm/mmap.c @@ -1255,18 +1255,6 @@ unsigned long do_mmap(struct file *file, if (mm->map_count > sysctl_max_map_count) return -ENOMEM; - /* Obtain the address to map to. we verify (or select) it and ensure - * that it represents a valid section of the address space. - */ - addr = get_unmapped_area(file, addr, len, pgoff, flags); - if (IS_ERR_VALUE(addr)) - return addr; - - if (flags & MAP_FIXED_NOREPLACE) { - if (find_vma_intersection(mm, addr, addr + len)) - return -EEXIST; - } - if (prot == PROT_EXEC) { pkey = execute_only_pkey(mm); if (pkey < 0) @@ -1280,6 +1268,18 @@ unsigned long do_mmap(struct file *file, vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; + /* Obtain the address to map to. we verify (or select) it and ensure + * that it represents a valid section of the address space. + */ + addr = __get_unmapped_area(file, addr, len, pgoff, flags, vm_flags); + if (IS_ERR_VALUE(addr)) + return addr; + + if (flags & MAP_FIXED_NOREPLACE) { + if (find_vma_intersection(mm, addr, addr + len)) + return -EEXIST; + } + if (flags & MAP_LOCKED) if (!can_do_mlock()) return -EPERM; @@ -1836,8 +1836,8 @@ unsigned long mm_get_unmapped_area_vmfla } unsigned long -get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, - unsigned long pgoff, unsigned long flags) +__get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, + unsigned long pgoff, unsigned long flags, vm_flags_t vm_flags) { unsigned long (*get_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long) @@ -1872,8 +1872,8 @@ get_unmapped_area(struct file *file, uns if (get_area) addr = get_area(file, addr, len, pgoff, flags); else - addr = mm_get_unmapped_area(current->mm, file, addr, len, - pgoff, flags); + addr = mm_get_unmapped_area_vmflags(current->mm, file, addr, len, + pgoff, flags, vm_flags); if (IS_ERR_VALUE(addr)) return addr; _ Patches currently in -mm which might be from rick.p.edgecombe@intel.com are proc-refactor-pde_get_unmapped_area-as-prep.patch mm-switch-mm-get_unmapped_area-to-a-flag.patch mm-introduce-arch_get_unmapped_area_vmflags.patch mm-remove-export-for-get_unmapped_area.patch mm-use-get_unmapped_area_vmflags.patch thp-add-thp_get_unmapped_area_vmflags.patch csky-use-initializer-for-struct-vm_unmapped_area_info.patch parisc-use-initializer-for-struct-vm_unmapped_area_info.patch powerpc-use-initializer-for-struct-vm_unmapped_area_info.patch treewide-use-initializer-for-struct-vm_unmapped_area_info.patch mm-take-placement-mappings-gap-into-account.patch x86-mm-implement-have_arch_unmapped_area_vmflags.patch x86-mm-care-about-shadow-stack-guard-gap-during-placement.patch selftests-x86-add-placement-guard-gap-test-for-shstk.patch