Merge tag 'xsa-5.19-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen security fixes from Juergen Gross:

 - XSA-403 (4 patches for blkfront and netfront drivers):

   Linux Block and Network PV device frontends don't zero memory regions
   before sharing them with the backend (CVE-2022-26365,
   CVE-2022-33740). Additionally the granularity of the grant table
   doesn't allow sharing less than a 4K page, leading to unrelated data
   residing in the same 4K page as data shared with a backend being
   accessible by such backend (CVE-2022-33741, CVE-2022-33742).

 - XSA-405 (1 patch for netfront driver, only 5.10 and newer):

   While adding logic to support XDP (eXpress Data Path), a code label
   was moved in a way allowing for SKBs having references (pointers)
   retained for further processing to nevertheless be freed.

 - XSA-406 (1 patch for Arm specific dom0 code):

   When mapping pages of guests on Arm, dom0 is using an rbtree to keep
   track of the foreign mappings.

   Updating of that rbtree is not always done completely with the
   related lock held, resulting in a small race window, which can be
   used by unprivileged guests via PV devices to cause inconsistencies
   of the rbtree. These inconsistencies can lead to Denial of Service
   (DoS) of dom0, e.g. by causing crashes or the inability to perform
   further mappings of other guests' memory pages.

* tag 'xsa-5.19-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/arm: Fix race in RB-tree based P2M accounting
  xen-netfront: restore __skb_queue_tail() positioning in xennet_get_responses()
  xen/blkfront: force data bouncing when backend is untrusted
  xen/netfront: force data bouncing when backend is untrusted
  xen/netfront: fix leaking data in shared pages
  xen/blkfront: fix leaking data in shared pages

1 files changed, 4 insertions, 2 deletions

diff --git a/arch/arm/xen/p2m.c b/arch/arm/xen/p2m.c
index 84a1cea1f43b..309648c17f48 100644
--- a/arch/arm/xen/p2m.c
+++ b/arch/arm/xen/p2m.c
@@ -63,11 +63,12 @@ out:
 
 unsigned long __pfn_to_mfn(unsigned long pfn)
 {
-	struct rb_node *n = phys_to_mach.rb_node;
+	struct rb_node *n;
 	struct xen_p2m_entry *entry;
 	unsigned long irqflags;
 
 	read_lock_irqsave(&p2m_lock, irqflags);
+	n = phys_to_mach.rb_node;
 	while (n) {
 		entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
 		if (entry->pfn <= pfn &&
@@ -152,10 +153,11 @@ bool __set_phys_to_machine_multi(unsigned long pfn,
 	int rc;
 	unsigned long irqflags;
 	struct xen_p2m_entry *p2m_entry;
-	struct rb_node *n = phys_to_mach.rb_node;
+	struct rb_node *n;
 
 	if (mfn == INVALID_P2M_ENTRY) {
 		write_lock_irqsave(&p2m_lock, irqflags);
+		n = phys_to_mach.rb_node;
 		while (n) {
 			p2m_entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
 			if (p2m_entry->pfn <= pfn &&