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 2AF044D599; Wed, 23 Oct 2024 22:44:06 +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=1729723447; cv=none; b=naM4JV3TbXXto43sqWc1rev3OAVRS8AbSWS8NBEXyYczOwharQXQ1NAsHvW49wlVnvC64wuPLWYhJn5qFfi3dk5IRjV/yQdjf0Jd6g5p5CDM0BCCab4oPnT1161qiP8z3WUsEmM8TJcCE/YAAKwlvOC6JJbfYBPzcK4yrXWdH44= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729723447; c=relaxed/simple; bh=PsS90EcA8znj69sCVf5xuwjv6vUgxYjA9PFSw3grQt8=; h=Date:To:From:Subject:Message-Id; b=IQP1Tnj9I+mRosUdEpy3i+b/XhN34e06oYVq3uxkU9ctgEzNDSdJmUlCCF4s/5KeGyu88D8oSMqw3wyjr4E8kQ2eG1qXivdHwdq85luGh1EESWNwwLnrl00oUmlbHR7coAU0x9rA6aowjZqNxY67juToncU0JF8CJ+mVnnEbzNw= 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=kEywILP4; 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="kEywILP4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F648C4CEC6; Wed, 23 Oct 2024 22:44:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1729723446; bh=PsS90EcA8znj69sCVf5xuwjv6vUgxYjA9PFSw3grQt8=; h=Date:To:From:Subject:From; b=kEywILP4QwUJtS0Qr/d/y83o0Hrl6j0CcgmwqszEXi6bVfbMfg7H2NY5SFylnd1r6 mVjC2pxCsLDsgWRFROVAhJZNGugDpkmyCXHdy4qAID9p8/mk7nDldrwgwKhVw6pO+A pWE0yR5VG3qwTetQZA6RpMd1pb2b2/o01ZO73o90= Date: Wed, 23 Oct 2024 15:44:06 -0700 To: mm-commits@vger.kernel.org,vbabka@suse.cz,torvalds@linux-foundation.org,stable@vger.kernel.org,Liam.Howlett@oracle.com,jannh@google.com,lorenzo.stoakes@oracle.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-refactor-map_deny_write_exec.patch added to mm-hotfixes-unstable branch Message-Id: <20241023224406.9F648C4CEC6@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm: refactor map_deny_write_exec() has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-refactor-map_deny_write_exec.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-refactor-map_deny_write_exec.patch This patch will later appear in the mm-hotfixes-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: Lorenzo Stoakes Subject: mm: refactor map_deny_write_exec() Date: Wed, 23 Oct 2024 21:38:28 +0100 Refactor the map_deny_write_exec() to not unnecessarily require a VMA parameter but rather to accept VMA flags parameters, which allows us to use this function early in mmap_region() in a subsequent commit. While we're here, we refactor the function to be more readable and add some additional documentation. Link: https://lkml.kernel.org/r/e82d23cebaa87fe5b767fecf9e730e0059066e63.1729715266.git.lorenzo.stoakes@oracle.com Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes Reported-by: Jann Horn Reviewed-by: Liam R. Howlett Reviewed-by: Vlastimil Babka Reviewed-by: Jann Horn Cc: Linus Torvalds Cc: Signed-off-by: Andrew Morton --- include/linux/mman.h | 21 ++++++++++++++++++--- mm/mmap.c | 2 +- mm/mprotect.c | 2 +- mm/vma.h | 2 +- 4 files changed, 21 insertions(+), 6 deletions(-) --- a/include/linux/mman.h~mm-refactor-map_deny_write_exec +++ a/include/linux/mman.h @@ -188,16 +188,31 @@ static inline bool arch_memory_deny_writ * * d) mmap(PROT_READ | PROT_EXEC) * mmap(PROT_READ | PROT_EXEC | PROT_BTI) + * + * This is only applicable if the user has set the Memory-Deny-Write-Execute + * (MDWE) protection mask for the current process. + * + * @old specifies the VMA flags the VMA originally possessed, and @new the ones + * we propose to set. + * + * Return: false if proposed change is OK, true if not ok and should be denied. */ -static inline bool map_deny_write_exec(struct vm_area_struct *vma, unsigned long vm_flags) +static inline bool map_deny_write_exec(unsigned long old, unsigned long new) { + /* If MDWE is disabled, we have nothing to deny. */ if (!test_bit(MMF_HAS_MDWE, ¤t->mm->flags)) return false; - if ((vm_flags & VM_EXEC) && (vm_flags & VM_WRITE)) + /* If the new VMA is not executable, we have nothing to deny. */ + if (!(new & VM_EXEC)) + return false; + + /* Under MDWE we do not accept newly writably executable VMAs... */ + if (new & VM_WRITE) return true; - if (!(vma->vm_flags & VM_EXEC) && (vm_flags & VM_EXEC)) + /* ...nor previously non-executable VMAs becoming executable. */ + if (!(old & VM_EXEC)) return true; return false; --- a/mm/mmap.c~mm-refactor-map_deny_write_exec +++ a/mm/mmap.c @@ -1504,7 +1504,7 @@ unsigned long mmap_region(struct file *f vma_set_anonymous(vma); } - if (map_deny_write_exec(vma, vma->vm_flags)) { + if (map_deny_write_exec(vma->vm_flags, vma->vm_flags)) { error = -EACCES; goto close_and_free_vma; } --- a/mm/mprotect.c~mm-refactor-map_deny_write_exec +++ a/mm/mprotect.c @@ -810,7 +810,7 @@ static int do_mprotect_pkey(unsigned lon break; } - if (map_deny_write_exec(vma, newflags)) { + if (map_deny_write_exec(vma->vm_flags, newflags)) { error = -EACCES; break; } --- a/mm/vma.h~mm-refactor-map_deny_write_exec +++ a/mm/vma.h @@ -42,7 +42,7 @@ struct vma_munmap_struct { int vma_count; /* Number of vmas that will be removed */ bool unlock; /* Unlock after the munmap */ bool clear_ptes; /* If there are outstanding PTE to be cleared */ - /* 1 byte hole */ + /* 2 byte hole */ unsigned long nr_pages; /* Number of pages being removed */ unsigned long locked_vm; /* Number of locked pages */ unsigned long nr_accounted; /* Number of VM_ACCOUNT pages */ _ Patches currently in -mm which might be from lorenzo.stoakes@oracle.com are fork-do-not-invoke-uffd-on-fork-if-error-occurs.patch fork-only-invoke-khugepaged-ksm-hooks-if-no-error.patch mm-vma-add-expand-only-vma-merge-mode-and-optimise-do_brk_flags.patch tools-testing-add-expand-only-mode-vma-test.patch mm-avoid-unsafe-vma-hook-invocation-when-error-arises-on-mmap-hook.patch mm-unconditionally-close-vmas-on-error.patch mm-refactor-map_deny_write_exec.patch mm-resolve-faulty-mmap_region-error-path-behaviour.patch tools-testing-add-additional-vma_internalh-stubs.patch mm-isolate-mmap-internal-logic-to-mm-vmac.patch mm-refactor-__mmap_region.patch mm-defer-second-attempt-at-merge-on-mmap.patch selftests-mm-add-pkey_sighandler_xx-hugetlb_dio-to-gitignore.patch mm-refactor-mm_access-to-not-return-null.patch mm-refactor-mm_access-to-not-return-null-fix.patch mm-madvise-unrestrict-process_madvise-for-current-process.patch maple_tree-do-not-hash-pointers-on-dump-in-debug-mode.patch tools-testing-fix-phys_addr_t-size-on-64-bit-systems.patch