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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 01:47:29 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 01:47:29 +0000 |
commit | 0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d (patch) | |
tree | a31f07c9bcca9d56ce61e9a1ffd30ef350d513aa /security/sandbox/chromium/base/memory/unsafe_shared_memory_region.h | |
parent | Initial commit. (diff) | |
download | firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.tar.xz firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.zip |
Adding upstream version 115.8.0esr.upstream/115.8.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'security/sandbox/chromium/base/memory/unsafe_shared_memory_region.h')
-rw-r--r-- | security/sandbox/chromium/base/memory/unsafe_shared_memory_region.h | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/security/sandbox/chromium/base/memory/unsafe_shared_memory_region.h b/security/sandbox/chromium/base/memory/unsafe_shared_memory_region.h new file mode 100644 index 0000000000..559d4c6830 --- /dev/null +++ b/security/sandbox/chromium/base/memory/unsafe_shared_memory_region.h @@ -0,0 +1,127 @@ +// Copyright 2018 The Chromium Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +#ifndef BASE_MEMORY_UNSAFE_SHARED_MEMORY_REGION_H_ +#define BASE_MEMORY_UNSAFE_SHARED_MEMORY_REGION_H_ + +#include "base/gtest_prod_util.h" +#include "base/macros.h" +#include "base/memory/platform_shared_memory_region.h" +#include "base/memory/shared_memory_mapping.h" + +namespace base { + +// Scoped move-only handle to a region of platform shared memory. The instance +// owns the platform handle it wraps. Mappings created by this region are +// writable. These mappings remain valid even after the region handle is moved +// or destroyed. +// +// NOTE: UnsafeSharedMemoryRegion cannot be converted to a read-only region. Use +// with caution as the region will be writable to any process with a handle to +// the region. +// +// Use this if and only if the following is true: +// - You do not need to share the region as read-only, and, +// - You need to have several instances of the region simultaneously, possibly +// in different processes, that can produce writable mappings. + +class BASE_EXPORT UnsafeSharedMemoryRegion { + public: + using MappingType = WritableSharedMemoryMapping; + // Creates a new UnsafeSharedMemoryRegion instance of a given size that can be + // used for mapping writable shared memory into the virtual address space. + // + // This call will fail if the process does not have sufficient permissions to + // create a shared memory region itself. See + // mojo::CreateUnsafeSharedMemoryRegion in + // mojo/public/cpp/base/shared_memory_utils.h for creating a shared memory + // region from a an unprivileged process where a broker must be used. + static UnsafeSharedMemoryRegion Create(size_t size); + using CreateFunction = decltype(Create); + + // Returns an UnsafeSharedMemoryRegion built from a platform-specific handle + // that was taken from another UnsafeSharedMemoryRegion instance. Returns an + // invalid region iff the |handle| is invalid. CHECK-fails if the |handle| + // isn't unsafe. + // This should be used only by the code passing a handle across + // process boundaries. + static UnsafeSharedMemoryRegion Deserialize( + subtle::PlatformSharedMemoryRegion handle); + + // Extracts a platform handle from the region. Ownership is transferred to the + // returned region object. + // This should be used only for sending the handle from the current + // process to another. + static subtle::PlatformSharedMemoryRegion TakeHandleForSerialization( + UnsafeSharedMemoryRegion region); + + // Default constructor initializes an invalid instance. + UnsafeSharedMemoryRegion(); + + // Move operations are allowed. + UnsafeSharedMemoryRegion(UnsafeSharedMemoryRegion&&); + UnsafeSharedMemoryRegion& operator=(UnsafeSharedMemoryRegion&&); + + // Destructor closes shared memory region if valid. + // All created mappings will remain valid. + ~UnsafeSharedMemoryRegion(); + + // Duplicates the underlying platform handle and creates a new + // UnsafeSharedMemoryRegion instance that owns the newly created handle. + // Returns a valid UnsafeSharedMemoryRegion on success, invalid otherwise. + // The current region instance remains valid in any case. + UnsafeSharedMemoryRegion Duplicate() const; + + // Maps the shared memory region into the caller's address space with write + // access. The mapped address is guaranteed to have an alignment of + // at least |subtle::PlatformSharedMemoryRegion::kMapMinimumAlignment|. + // Returns a valid WritableSharedMemoryMapping instance on success, invalid + // otherwise. + WritableSharedMemoryMapping Map() const; + + // Same as above, but maps only |size| bytes of the shared memory region + // starting with the given |offset|. |offset| must be aligned to value of + // |SysInfo::VMAllocationGranularity()|. Returns an invalid mapping if + // requested bytes are out of the region limits. + WritableSharedMemoryMapping MapAt(off_t offset, size_t size) const; + + // Whether the underlying platform handle is valid. + bool IsValid() const; + + // Returns the maximum mapping size that can be created from this region. + size_t GetSize() const { + DCHECK(IsValid()); + return handle_.GetSize(); + } + + // Returns 128-bit GUID of the region. + const UnguessableToken& GetGUID() const { + DCHECK(IsValid()); + return handle_.GetGUID(); + } + + // Returns a platform shared memory handle. |this| remains the owner of the + // handle. + subtle::PlatformSharedMemoryRegion::PlatformHandle GetPlatformHandle() const { + DCHECK(IsValid()); + return handle_.GetPlatformHandle(); + } + + private: + friend class SharedMemoryHooks; + + explicit UnsafeSharedMemoryRegion(subtle::PlatformSharedMemoryRegion handle); + + static void set_create_hook(CreateFunction* hook) { create_hook_ = hook; } + + static CreateFunction* create_hook_; + + subtle::PlatformSharedMemoryRegion handle_; + + DISALLOW_COPY_AND_ASSIGN(UnsafeSharedMemoryRegion); +}; + +} // namespace base + +#endif // BASE_MEMORY_UNSAFE_SHARED_MEMORY_REGION_H_ |