xen: patch with XSA-475

Xen Security Advisory #475

       x86: Incorrect input sanitisation in Viridian hypercalls

Some Viridian hypercalls can specify a mask of vCPU IDs as an input, in
one of three formats.  Xen has boundary checking bugs with all three
formats, which can cause out-of-bounds reads and writes while processing
the inputs.

 * CVE-2025-58147.  Hypercalls using the HV_VP_SET Sparse format can
   cause vpmask_set() to write out of bounds when converting the bitmap
   to Xen's format.

 * CVE-2025-58148.  Hypercalls using any input format can cause
   send_ipi() to read d->vcpu[] out-of-bounds, and operate on a wild
   vCPU pointer.

Signed-off-by: Fernando Rodrigues <alpha@sigmasquadron.net>

(cherry picked from commit 901ddad083)

pkgs/by-name/xe/xen/package.nix

@@ -34,5 +34,15 @@ buildXenPackage.override { inherit python3Packages; } {
       url = "https://xenbits.xen.org/xsa/xsa473-2.patch";
       hash = "sha256-tGuIGxJFBXbckIruSUeTyrM6GabdIj6Pr3cVxeDvNNY=";
     })
+
+    # XSA 475
+    (fetchpatch {
+      url = "https://xenbits.xen.org/xsa/xsa475-4.19-1.patch";
+      hash = "sha256-Bzvtr12g+7+M9jY9Nt2jd41CwYTL+h2fuwzJFsxroio=";
+    })
+    (fetchpatch {
+      url = "https://xenbits.xen.org/xsa/xsa475-4.19-2.patch";
+      hash = "sha256-257GucAOUoK0gNSDglU7F+qvaT47FebFPW8hYzMp9XE=";
+    })
   ];
 }