i2p/haiku-beta6
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Improved safety for user memory accesses.

Browse Source 
* Changed IS_USER_ADDRESS to check an address using USER_BASE and
  USER_SIZE, rather than just !IS_KERNEL_ADDRESS. The old check would
  allow user buffers to point into the physical memory map area.
* Added an unmapped hole at the end of the bottom half of the address
  space which catches buffers that cross into the uncanonical address
  region. This also removes the need to check for uncanonical return
  addresses in the syscall handler, it is no longer possible for the
  return address to be uncanonical under normal circumstances. All
  cases in which the return address might be changed by the kernel
  are still handled via the IRET path.
This commit is contained in:
Alex Smith
2012-08-02 09:32:33 +01:00
parent b77772725c
commit d93ed09564
7 changed files with 25 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files
headers/private/kernel/kernel.h
+8 -1
View File
@@ -31,7 +31,14 @@
#endif
// Buffers passed in from user-space shouldn't point into the kernel.
#define IS_USER_ADDRESS(x) (!IS_KERNEL_ADDRESS(x))
#if USER_BASE == 0
# define IS_USER_ADDRESS(x) ((addr_t)(x) <= USER_TOP)
#elif USER_TOP == __HAIKU_ADDR_MAX
# define IS_USER_ADDRESS(x) ((addr_t)(x) >= USER_BASE)
#else
# define IS_USER_ADDRESS(x) \
((addr_t)(x) >= USER_BASE && (addr_t)(x) <= USER_TOP)
#endif
#define DEBUG_KERNEL_STACKS
// Note, debugging kernel stacks doesn't really work yet. Since the