Changeset 258620 in webkit

Timestamp:

Mar 17, 2020 8:32:31 PM (4 years ago)

Author:

ddkilzer@apple.com

Message:

SharedMemory::Handle::m_size should be more consistent
<​https://webkit.org/b/209007>
<rdar://problem/60340890>

Reviewed by Darin Adler.

• Platform/cocoa/SharedMemoryCocoa.cpp:

(WebKit::SharedMemory::Handle::decode):

• Return early if an invalid size is decoded.

(WebKit::SharedMemory::map):

• Drive-by fix to change '0' to 'nullptr'.
• Since all known methods of creating a SharedMemory::Handle() set SharedMemory::Handle::m_size to a value of round_page(), this means we can also change round_page(handle.m_size) to handle.m_size in the call to mach_vm_map() since we know they're equal.

Location:

trunk/Source/WebKit

Files:

• ChangeLog (modified) (1 diff)
• Platform/cocoa/SharedMemoryCocoa.cpp (modified) (2 diffs)

trunk/Source/WebKit/ChangeLog

@@ +1 @@
+2020-03-17  David Kilzer  <ddkilzer@apple.com>
+
+        SharedMemory::Handle::m_size should be more consistent
+        <https://webkit.org/b/209007>
+        <rdar://problem/60340890>
+
+        Reviewed by Darin Adler.
+
+        * Platform/cocoa/SharedMemoryCocoa.cpp:
+        (WebKit::SharedMemory::Handle::decode):
+        - Return early if an invalid `size` is decoded.
+        (WebKit::SharedMemory::map):
+        - Drive-by fix to change '0' to 'nullptr'.
+        - Since all known methods of creating a SharedMemory::Handle()
+          set SharedMemory::Handle::m_size to a value of round_page(),
+          this means we can also change `round_page(handle.m_size)` to
+          `handle.m_size` in the call to mach_vm_map() since we know
+          they're equal.
+
 2020-03-17  Commit Queue  <commit-queue@webkit.org>
 

trunk/Source/WebKit/Platform/cocoa/SharedMemoryCocoa.cpp

@@ -94 +94 @@
     if (!decoder.decode(size))
         return false;
+    if (size != round_page(size))
+        return false;
 
     IPC::MachPort machPort;
@@ -191 +193 @@
 {
     if (handle.isNull())
-        return 0;
-    
+        return nullptr;
+
     ASSERT(round_page(handle.m_size) == handle.m_size);
 
     vm_prot_t vmProtection = machProtection(protection);
     mach_vm_address_t mappedAddress = 0;
-    kern_return_t kr = mach_vm_map(mach_task_self(), &mappedAddress, round_page(handle.m_size), 0, VM_FLAGS_ANYWHERE, handle.m_port, 0, false, vmProtection, vmProtection, VM_INHERIT_NONE);
+    kern_return_t kr = mach_vm_map(mach_task_self(), &mappedAddress, handle.m_size, 0, VM_FLAGS_ANYWHERE, handle.m_port, 0, false, vmProtection, vmProtection, VM_INHERIT_NONE);
 #if RELEASE_LOG_DISABLED
     if (kr != KERN_SUCCESS)