X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/2dced7af2b695f87fe26496a3e73c219b7880cbc..4bd07ac2140668789aa3ee8ec4dde4a3e0a3bba5:/osfmk/mach/vm_param.h

diff --git a/osfmk/mach/vm_param.h b/osfmk/mach/vm_param.h
index 6a33043a6..1fa361488 100644
--- a/osfmk/mach/vm_param.h
+++ b/osfmk/mach/vm_param.h
@@ -308,7 +308,9 @@ extern vm_offset_t      vm_elinkedit;
  * VM_KERNEL_UNSLIDE_OR_ADDRPERM:
  *     Use this macro when you are exposing an address to userspace that could
  *     come from either kernel text/data *or* the heap. This is a rare case,
- *     but one that does come up and must be handled correctly.
+ *     but one that does come up and must be handled correctly. If the argument
+ *     is known to be lower than any potential heap address, no transformation
+ *     is applied, to avoid revealing the operation on a constant.
  *
  * Nesting of these macros should be considered invalid.
  */
@@ -333,7 +335,7 @@ extern vm_offset_t      vm_elinkedit;
           VM_KERNEL_IS_PRELINKINFO(_v) ||   \
           VM_KERNEL_IS_KEXT_LINKEDIT(_v)) ?         \
 			(vm_offset_t)(_v) - vm_kernel_slide :    \
-			VM_KERNEL_ADDRPERM(_v))
+		 ((vm_offset_t)(_v) >= VM_MIN_KERNEL_AND_KEXT_ADDRESS ? VM_KERNEL_ADDRPERM(_v) : (vm_offset_t)(_v)))
 	
 
 #endif	/* XNU_KERNEL_PRIVATE */