[Xen-changelog] [xen-unstable] [IA64] Fix incorrect NVRAM saving if domain is destroyed by config error

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Alex Williamson <alex.williamson@xxxxxx>
# Date 1183388724 21600
# Node ID 38d0618868738b03611bdbb9f3fe29c73f1c34dd
# Parent  89596982890b78ebceffc4c5803662adc3dddc73
[IA64] Fix incorrect NVRAM saving if domain is destroyed by config error

Nvram saving is always executed even if a domain is destroyed by a
configuration parameter error.  In this case, Nvram saving function
will get a bad address for the NVRAM data and save garbage into the
NVRAM file. Configuring a wrong vif parameter can expose this issue.

This patch fixes the issue by adding an address check function in
NVRAM saving path.

Signed-off-by: Zhang Xin <xing.z.zhang@xxxxxxxxx>
---
 tools/libxc/ia64/xc_ia64_hvm_build.c |   21 ++++++++++++++++++++-
 xen/include/public/arch-ia64.h       |    6 ++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff -r 89596982890b -r 38d061886873 tools/libxc/ia64/xc_ia64_hvm_build.c
--- a/tools/libxc/ia64/xc_ia64_hvm_build.c      Mon Jul 02 08:51:59 2007 -0600
+++ b/tools/libxc/ia64/xc_ia64_hvm_build.c      Mon Jul 02 09:05:24 2007 -0600
@@ -623,6 +623,21 @@ copy_from_nvram_to_GFW(int xc_handle, ui
 
 
 /*
+ *Check is the address where NVRAM data located valid
+ */
+static int is_valid_address(void *addr)
+{
+    struct nvram_save_addr *p = (struct nvram_save_addr *)addr;        
+
+    if ( p->signature == NVRAM_VALID_SIG )
+        return 1;
+    else {
+        PERROR("Invalid nvram signature. Nvram save failed!\n");
+        return 0;
+    }
+}
+
+/*
  * GFW use 4k page. when doing foreign map, we should 16k align
  * the address and map one more page to guarantee all 64k nvram data 
  * can be got.
@@ -667,7 +682,11 @@ copy_from_GFW_to_nvram(int xc_handle, ui
         return -1;
     }
 
-    addr_from_GFW_4k_align = *((uint64_t *)tmp_ptr);
+    /* Check is NVRAM data vaild */
+    if ( !is_valid_address(tmp_ptr) )
+        return -1;
+
+    addr_from_GFW_4k_align = ((struct nvram_save_addr *)tmp_ptr)->addr;
     munmap(tmp_ptr, PAGE_SIZE);
 
     // align address to 16k
diff -r 89596982890b -r 38d061886873 xen/include/public/arch-ia64.h
--- a/xen/include/public/arch-ia64.h    Mon Jul 02 08:51:59 2007 -0600
+++ b/xen/include/public/arch-ia64.h    Mon Jul 02 09:05:24 2007 -0600
@@ -116,6 +116,12 @@ typedef unsigned long xen_ulong_t;
 /* Nvram belongs to GFW memory space  */
 #define NVRAM_SIZE       (MEM_K * 64)
 #define NVRAM_START      (GFW_START + 10 * MEM_M)
+
+#define NVRAM_VALID_SIG 0x4650494e45584948             // "HIXENIPF"
+struct nvram_save_addr {
+    unsigned long addr;
+    unsigned long signature;
+};
 
 struct pt_fpreg {
     union {

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