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File 5a79d7ed-libxc-packed-initrd-dont-fail-domain-creation.patch of Package xen (Revision 53f017217d750d8903a37544fbff23d5)

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References: bsc#1055047

# Commit d0115f96ea633fd6d668f2c067785912c0ad4c00
# Date 2018-02-06 17:29:33 +0100
# Author Jan Beulich <jbeulich@suse.com>
# Committer Jan Beulich <jbeulich@suse.com>
libxc: don't fail domain creation when unpacking initrd fails

At least Linux kernels have been able to work with gzip-ed initrd for
quite some time; initrd compressed with other methods aren't even being
attempted to unpack. Furthermore the unzip-ing routine used here isn't
capable of dealing with various forms of concatenated files, each of
which was gzip-ed separately (it is this particular case which has been
the source of observed VM creation failures).

Hence, if unpacking fails, simply hand the compressed blob to the guest
as is.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>

--- a/tools/libxc/include/xc_dom.h
+++ b/tools/libxc/include/xc_dom.h
@@ -291,7 +291,6 @@ int xc_dom_mem_init(struct xc_dom_image
 int xc_dom_kernel_check_size(struct xc_dom_image *dom, size_t sz);
 int xc_dom_kernel_max_size(struct xc_dom_image *dom, size_t sz);
 
-int xc_dom_ramdisk_check_size(struct xc_dom_image *dom, size_t sz);
 int xc_dom_ramdisk_max_size(struct xc_dom_image *dom, size_t sz);
 
 int xc_dom_devicetree_max_size(struct xc_dom_image *dom, size_t sz);
--- a/tools/libxc/xc_dom_core.c
+++ b/tools/libxc/xc_dom_core.c
@@ -314,22 +314,6 @@ int xc_dom_kernel_check_size(struct xc_d
     return 0;
 }
 
-int xc_dom_ramdisk_check_size(struct xc_dom_image *dom, size_t sz)
-{
-    /* No limit */
-    if ( !dom->max_ramdisk_size )
-        return 0;
-
-    if ( sz > dom->max_ramdisk_size )
-    {
-        xc_dom_panic(dom->xch, XC_INVALID_KERNEL,
-                     "ramdisk image too large");
-        return 1;
-    }
-
-    return 0;
-}
-
 /* ------------------------------------------------------------------------ */
 /* read files, copy memory blocks, with transparent gunzip                  */
 
@@ -996,16 +980,27 @@ static int xc_dom_build_ramdisk(struct x
     void *ramdiskmap;
 
     if ( !dom->ramdisk_seg.vstart )
-    {
         unziplen = xc_dom_check_gzip(dom->xch,
                                      dom->ramdisk_blob, dom->ramdisk_size);
-        if ( xc_dom_ramdisk_check_size(dom, unziplen) != 0 )
-            unziplen = 0;
-    }
     else
         unziplen = 0;
 
-    ramdisklen = unziplen ? unziplen : dom->ramdisk_size;
+    ramdisklen = max(unziplen, dom->ramdisk_size);
+    if ( dom->max_ramdisk_size )
+    {
+        if ( unziplen && ramdisklen > dom->max_ramdisk_size )
+        {
+            ramdisklen = min(unziplen, dom->ramdisk_size);
+            if ( unziplen > ramdisklen )
+                unziplen = 0;
+        }
+        if ( ramdisklen > dom->max_ramdisk_size )
+        {
+            xc_dom_panic(dom->xch, XC_INVALID_KERNEL,
+                         "ramdisk image too large");
+            goto err;
+        }
+    }
 
     if ( xc_dom_alloc_segment(dom, &dom->ramdisk_seg, "ramdisk",
                               dom->ramdisk_seg.vstart, ramdisklen) != 0 )
@@ -1020,11 +1015,18 @@ static int xc_dom_build_ramdisk(struct x
     if ( unziplen )
     {
         if ( xc_dom_do_gunzip(dom->xch, dom->ramdisk_blob, dom->ramdisk_size,
-                              ramdiskmap, ramdisklen) == -1 )
+                              ramdiskmap, unziplen) != -1 )
+            return 0;
+        if ( dom->ramdisk_size > ramdisklen )
             goto err;
     }
-    else
-        memcpy(ramdiskmap, dom->ramdisk_blob, dom->ramdisk_size);
+
+    /* Fall back to handing over the raw blob. */
+    memcpy(ramdiskmap, dom->ramdisk_blob, dom->ramdisk_size);
+    /* If an unzip attempt was made, the buffer may no longer be all zero. */
+    if ( unziplen > dom->ramdisk_size )
+        memset(ramdiskmap + dom->ramdisk_size, 0,
+               unziplen - dom->ramdisk_size);
 
     return 0;

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File 5a79d7ed-libxc-packed-initrd-dont-fail-domain-creation.patch of Package xen (Revision 53f017217d750d8903a37544fbff23d5)

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