[Xen-changelog] [xen master] x86: make sure module array is large enough in pvh-boot.c

[patchbot@xxxxxxx]

commit c88397db5c3fa5e52da05234fba046bda075af29
Author:     Wei Liu <wei.liu2@xxxxxxxxxx>
AuthorDate: Wed Sep 26 11:52:54 2018 +0100
Commit:     Wei Liu <wei.liu2@xxxxxxxxxx>
CommitDate: Mon Oct 1 11:12:21 2018 +0100

    x86: make sure module array is large enough in pvh-boot.c
    
    The relocation code in __start_xen requires one extra element in the
    module array. By the looks of it the temporary array is already large
    enough. Panic if that's not the case.
    
    While at it, turn an ASSERT to panic() as well.
    
    Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/guest/pvh-boot.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/guest/pvh-boot.c b/xen/arch/x86/guest/pvh-boot.c
index 0e9e5bfdf6..6e81b32b92 100644
--- a/xen/arch/x86/guest/pvh-boot.c
+++ b/xen/arch/x86/guest/pvh-boot.c
@@ -42,7 +42,17 @@ static void __init convert_pvh_info(void)
     module_t *mod;
     unsigned int i;
 
-    ASSERT(pvh_info->magic == XEN_HVM_START_MAGIC_VALUE);
+    if ( pvh_info->magic != XEN_HVM_START_MAGIC_VALUE )
+        panic("Magic value is wrong: %x\n", pvh_info->magic);
+
+    /*
+     * Temporary module array needs to be at least one element bigger than
+     * required. The extra element is used to aid relocation. See
+     * arch/x86/setup.c:__start_xen().
+     */
+    if ( ARRAY_SIZE(pvh_mbi_mods) <= pvh_info->nr_modules )
+        panic("The module array is too small, size %zu, requested %u\n",
+              ARRAY_SIZE(pvh_mbi_mods), pvh_info->nr_modules);
 
     /*
      * Turn hvm_start_info into mbi. Luckily all modules are placed under 4GB
--
generated by git-patchbot for /home/xen/git/xen.git#master

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