From: jeffxu@chromium.org
To: akpm@linux-foundation.org, keescook@chromium.org, sroettger@google.com
Cc: jeffxu@google.com, jorgelo@chromium.org, groeck@chromium.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-mm@kvack.org, jannh@google.com, surenb@google.com,
alex.sierra@amd.com, apopple@nvidia.com,
aneesh.kumar@linux.ibm.com, axelrasmussen@google.com,
ben@decadent.org.uk, catalin.marinas@arm.com, david@redhat.com,
dwmw@amazon.co.uk, ying.huang@intel.com, hughd@google.com,
joey.gouly@arm.com, corbet@lwn.net, wangkefeng.wang@huawei.com,
Liam.Howlett@oracle.com, torvalds@linux-foundation.org,
lstoakes@gmail.com, willy@infradead.org, mawupeng1@huawei.com,
linmiaohe@huawei.com, namit@vmware.com, peterx@redhat.com,
peterz@infradead.org, ryan.roberts@arm.com, shr@devkernel.io,
vbabka@suse.cz, xiujianfeng@huawei.com, yu.ma@intel.com,
zhangpeng362@huawei.com, dave.hansen@intel.com, luto@kernel.org,
linux-hardening@vger.kernel.org
Subject: [RFC PATCH v1 3/8] mseal: add can_modify_mm and can_modify_vma
Date: Mon, 16 Oct 2023 14:38:22 +0000 [thread overview]
Message-ID: <20231016143828.647848-4-jeffxu@chromium.org> (raw)
In-Reply-To: <20231016143828.647848-1-jeffxu@chromium.org>
From: Jeff Xu <jeffxu@google.com>
can_modify_mm:
checks sealing flags for given memory range.
can_modify_vma:
checks sealing flags for given vma.
Signed-off-by: Jeff Xu <jeffxu@google.com>
---
include/linux/mm.h | 34 ++++++++++++++++++++++++++
mm/mseal.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 94 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e790b91a0cd4..aafdb68950f8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -257,6 +257,18 @@ extern struct rw_semaphore nommu_region_sem;
extern unsigned int kobjsize(const void *objp);
#endif
+enum caller_origin {
+ ON_BEHALF_OF_KERNEL = 0,
+ ON_BEHALF_OF_USERSPACE,
+};
+
+enum mm_action {
+ MM_ACTION_MPROTECT,
+ MM_ACTION_MUNMAP,
+ MM_ACTION_MREMAP,
+ MM_ACTION_MMAP,
+};
+
/*
* vm_seals in vm_area_struct, see mm_types.h.
*/
@@ -3302,6 +3314,28 @@ static inline void mm_populate(unsigned long addr, unsigned long len)
static inline void mm_populate(unsigned long addr, unsigned long len) {}
#endif
+#ifdef CONFIG_MSEAL
+extern bool can_modify_mm(struct mm_struct *mm, unsigned long start,
+ unsigned long end, enum mm_action action,
+ enum caller_origin called);
+
+extern bool can_modify_vma(struct vm_area_struct *vma, enum mm_action action,
+ enum caller_origin called);
+#else
+static inline bool can_modify_mm(struct mm_struct *mm, unsigned long start,
+ unsigned long end, enum mm_action action,
+ enum caller_origin called)
+{
+ return true;
+}
+
+static inline bool can_modify_vma(struct vm_area_struct *vma, enum mm_action action,
+ enum caller_origin called)
+{
+ return true;
+}
+#endif
+
/* These take the mm semaphore themselves */
extern int __must_check vm_brk(unsigned long, unsigned long);
extern int __must_check vm_brk_flags(unsigned long, unsigned long, unsigned long);
diff --git a/mm/mseal.c b/mm/mseal.c
index 615b6e06ab44..3285ef6b95a6 100644
--- a/mm/mseal.c
+++ b/mm/mseal.c
@@ -36,6 +36,66 @@ static bool can_do_mseal(unsigned int types, unsigned int flags)
return true;
}
+/*
+ * check if a vma is sealed for modification.
+ * return true, if modification is allowed.
+ */
+bool can_modify_vma(struct vm_area_struct *vma, enum mm_action action,
+ enum caller_origin called)
+{
+ if (called == ON_BEHALF_OF_KERNEL)
+ return true;
+
+ switch (action) {
+ case MM_ACTION_MPROTECT:
+ if (vma->vm_seals & VM_SEAL_MPROTECT)
+ return false;
+ break;
+
+ case MM_ACTION_MUNMAP:
+ if (vma->vm_seals & VM_SEAL_MUNMAP)
+ return false;
+ break;
+
+ case MM_ACTION_MREMAP:
+ if (vma->vm_seals & VM_SEAL_MREMAP)
+ return false;
+ break;
+
+ case MM_ACTION_MMAP:
+ if (vma->vm_seals & VM_SEAL_MMAP)
+ return false;
+ break;
+ }
+
+ return true;
+}
+
+/*
+ * Check if the vmas of a memory range are allowed to be modified.
+ * the memory ranger can have a gap (unallocated memory).
+ * return true, if it is allowed.
+ */
+bool can_modify_mm(struct mm_struct *mm, unsigned long start, unsigned long end,
+ enum mm_action action, enum caller_origin called)
+{
+ struct vm_area_struct *vma;
+
+ VMA_ITERATOR(vmi, mm, start);
+
+ if (called == ON_BEHALF_OF_KERNEL)
+ return true;
+
+ /* going through each vma to check */
+ for_each_vma_range(vmi, vma, end) {
+ if (!can_modify_vma(vma, action, called))
+ return false;
+ }
+
+ /* Allow by default. */
+ return true;
+}
+
/*
* Check if a seal type can be added to VMA.
*/
--
2.42.0.609.gbb76f46606-goog
next prev parent reply other threads:[~2023-10-16 14:39 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-16 14:38 [RFC PATCH v1 0/8] Introduce mseal() syscall jeffxu
2023-10-16 14:38 ` [RFC PATCH v1 1/8] Add mseal syscall jeffxu
2023-10-16 15:05 ` Greg KH
2023-10-17 6:50 ` Jeff Xu
2023-10-16 14:38 ` [RFC PATCH v1 2/8] Wire up " jeffxu
2023-10-16 14:38 ` jeffxu [this message]
2023-10-16 14:38 ` [RFC PATCH v1 4/8] mseal: seal mprotect jeffxu
2023-10-16 14:38 ` [RFC PATCH v1 5/8] mseal munmap jeffxu
2023-10-16 14:38 ` [RFC PATCH v1 6/8] mseal mremap jeffxu
2023-10-16 14:38 ` [RFC PATCH v1 7/8] mseal mmap jeffxu
2023-10-16 14:38 ` [RFC PATCH v1 8/8] selftest mm/mseal mprotect/munmap/mremap/mmap jeffxu
2023-10-16 15:18 ` [RFC PATCH v1 0/8] Introduce mseal() syscall Matthew Wilcox
2023-10-17 8:34 ` Jeff Xu
2023-10-17 12:56 ` Matthew Wilcox
2023-10-17 15:29 ` Pedro Falcato
2023-10-17 21:33 ` Jeff Xu
2023-10-17 22:35 ` Pedro Falcato
2023-10-18 18:20 ` Jeff Xu
2023-10-19 17:30 ` Jeff Xu
2023-10-19 22:47 ` Pedro Falcato
2023-10-19 23:06 ` Linus Torvalds
2023-10-23 17:44 ` Jeff Xu
2023-10-23 17:42 ` Jeff Xu
2023-10-16 17:23 ` Linus Torvalds
2023-10-17 9:07 ` Jeff Xu
2023-10-17 17:22 ` Linus Torvalds
2023-10-17 18:20 ` Theo de Raadt
2023-10-17 18:38 ` Linus Torvalds
2023-10-17 18:55 ` Theo de Raadt
2023-10-19 8:00 ` Stephen Röttger
2023-10-20 16:27 ` Theo de Raadt
2023-10-24 10:42 ` Stephen Röttger
2023-10-17 23:01 ` Jeff Xu
2023-10-17 23:56 ` Theo de Raadt
2023-10-18 3:18 ` Jeff Xu
2023-10-18 3:37 ` Theo de Raadt
2023-10-18 15:17 ` Matthew Wilcox
2023-10-18 18:54 ` Jeff Xu
2023-10-18 20:36 ` Theo de Raadt
2023-10-19 8:28 ` Stephen Röttger
2023-10-20 15:55 ` Theo de Raadt
2023-10-16 17:34 ` Jann Horn
2023-10-17 8:42 ` Jeff Xu
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