diff options
Diffstat (limited to 'system/xen/xsa/xsa224-0001-gnttab-Fix-handling-of-dev_bus_addr-during-unmap.patch')
-rw-r--r-- | system/xen/xsa/xsa224-0001-gnttab-Fix-handling-of-dev_bus_addr-during-unmap.patch | 111 |
1 files changed, 0 insertions, 111 deletions
diff --git a/system/xen/xsa/xsa224-0001-gnttab-Fix-handling-of-dev_bus_addr-during-unmap.patch b/system/xen/xsa/xsa224-0001-gnttab-Fix-handling-of-dev_bus_addr-during-unmap.patch deleted file mode 100644 index 6a55f86b07..0000000000 --- a/system/xen/xsa/xsa224-0001-gnttab-Fix-handling-of-dev_bus_addr-during-unmap.patch +++ /dev/null @@ -1,111 +0,0 @@ -From 9808ed0b1ebc3a5d2aa08a9ff91fcf3ecb42bc9f Mon Sep 17 00:00:00 2001 -From: George Dunlap <george.dunlap@citrix.com> -Date: Thu, 15 Jun 2017 16:24:02 +0100 -Subject: [PATCH 1/4] gnttab: Fix handling of dev_bus_addr during unmap - -If a grant has been mapped with the GNTTAB_device_map flag, calling -grant_unmap_ref() with dev_bus_addr set to zero should cause the -GNTTAB_device_map part of the mapping to be left alone. - -Unfortunately, at the moment, op->dev_bus_addr is implicitly checked -before clearing the map and adjusting the pin count, but only the bits -above 12; and it is not checked at all before dropping page -references. This means a guest can repeatedly make such a call to -cause the reference count to drop to zero, causing the page to be -freed and re-used, even though it's still mapped in its pagetables. - -To fix this, always check op->dev_bus_addr explicitly for being -non-zero, as well as op->flag & GNTMAP_device_map, before doing -operations on the device_map. - -While we're here, make the logic a bit cleaner: - -* Always initialize op->frame to zero and set it from act->frame, to reduce the -chance of untrusted input being used - -* Explicitly check the full dev_bus_addr against act->frame << - PAGE_SHIFT, rather than ignoring the lower 12 bits - -This is part of XSA-224. - -Reported-by: Jan Beulich <jbeulich@suse.com> -Signed-off-by: George Dunlap <george.dunlap@citrix.com> -Signed-off-by: Jan Beulich <jbeulich@suse.com> ---- - xen/common/grant_table.c | 23 +++++++++++------------ - 1 file changed, 11 insertions(+), 12 deletions(-) - -diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c -index ba10e76..2671761 100644 ---- a/xen/common/grant_table.c -+++ b/xen/common/grant_table.c -@@ -1085,8 +1085,6 @@ __gnttab_unmap_common( - ld = current->domain; - lgt = ld->grant_table; - -- op->frame = (unsigned long)(op->dev_bus_addr >> PAGE_SHIFT); -- - if ( unlikely(op->handle >= lgt->maptrack_limit) ) - { - gdprintk(XENLOG_INFO, "Bad handle (%d).\n", op->handle); -@@ -1169,16 +1167,14 @@ __gnttab_unmap_common( - goto act_release_out; - } - -- if ( op->frame == 0 ) -- { -- op->frame = act->frame; -- } -- else -+ op->frame = act->frame; -+ -+ if ( op->dev_bus_addr ) - { -- if ( unlikely(op->frame != act->frame) ) -+ if ( unlikely(op->dev_bus_addr != pfn_to_paddr(act->frame)) ) - PIN_FAIL(act_release_out, GNTST_general_error, -- "Bad frame number doesn't match gntref. (%lx != %lx)\n", -- op->frame, act->frame); -+ "Bus address doesn't match gntref (%"PRIx64" != %"PRIpaddr")\n", -+ op->dev_bus_addr, pfn_to_paddr(act->frame)); - - map->flags &= ~GNTMAP_device_map; - } -@@ -1271,7 +1267,8 @@ __gnttab_unmap_common_complete(struct gnttab_unmap_common *op) - else - status = &status_entry(rgt, op->ref); - -- if ( unlikely(op->frame != act->frame) ) -+ if ( op->dev_bus_addr && -+ unlikely(op->dev_bus_addr != pfn_to_paddr(act->frame)) ) - { - /* - * Suggests that __gntab_unmap_common failed early and so -@@ -1282,7 +1279,7 @@ __gnttab_unmap_common_complete(struct gnttab_unmap_common *op) - - pg = mfn_to_page(op->frame); - -- if ( op->flags & GNTMAP_device_map ) -+ if ( op->dev_bus_addr && (op->flags & GNTMAP_device_map) ) - { - if ( !is_iomem_page(act->frame) ) - { -@@ -1353,6 +1350,7 @@ __gnttab_unmap_grant_ref( - /* Intialise these in case common contains old state */ - common->new_addr = 0; - common->rd = NULL; -+ common->frame = 0; - - __gnttab_unmap_common(common); - op->status = common->status; -@@ -1417,6 +1415,7 @@ __gnttab_unmap_and_replace( - /* Intialise these in case common contains old state */ - common->dev_bus_addr = 0; - common->rd = NULL; -+ common->frame = 0; - - __gnttab_unmap_common(common); - op->status = common->status; --- -2.1.4 - |