* [PATCH] x86/p2m: fix p2m_add_foreign error path
@ 2021-01-04 9:03 Roger Pau Monne
2021-01-04 10:45 ` Andrew Cooper
0 siblings, 1 reply; 2+ messages in thread
From: Roger Pau Monne @ 2021-01-04 9:03 UTC (permalink / raw)
To: xen-devel
Cc: Roger Pau Monne, Jan Beulich, Andrew Cooper, George Dunlap, Wei Liu
One of the error paths in p2m_add_foreign could call put_page with a
NULL page, thus triggering a fault.
Split the checks into two different if statements, so the appropriate
error path can be taken.
Fixes: 173ae325026bd ('x86/p2m: tidy p2m_add_foreign() a little')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
xen/arch/x86/mm/p2m.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 487959b121..a4ebfc9b21 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -2601,8 +2601,13 @@ static int p2m_add_foreign(struct domain *tdom, unsigned long fgfn,
* ram_rw | ram_logdirty | ram_ro | paging_out.
*/
page = get_page_from_gfn(fdom, fgfn, &p2mt, P2M_ALLOC);
- if ( !page ||
- !p2m_is_ram(p2mt) || p2m_is_shared(p2mt) || p2m_is_hole(p2mt) )
+ if ( !page )
+ {
+ rc = -EINVAL;
+ goto out;
+ }
+
+ if ( !p2m_is_ram(p2mt) || p2m_is_shared(p2mt) || p2m_is_hole(p2mt) )
{
rc = -EINVAL;
goto put_one;
--
2.29.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] x86/p2m: fix p2m_add_foreign error path
2021-01-04 9:03 [PATCH] x86/p2m: fix p2m_add_foreign error path Roger Pau Monne
@ 2021-01-04 10:45 ` Andrew Cooper
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Cooper @ 2021-01-04 10:45 UTC (permalink / raw)
To: Roger Pau Monne, xen-devel; +Cc: Jan Beulich, George Dunlap, Wei Liu
On 04/01/2021 09:03, Roger Pau Monne wrote:
> One of the error paths in p2m_add_foreign could call put_page with a
> NULL page, thus triggering a fault.
>
> Split the checks into two different if statements, so the appropriate
> error path can be taken.
>
> Fixes: 173ae325026bd ('x86/p2m: tidy p2m_add_foreign() a little')
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked and committed.
~Andrew
^ permalink raw reply [flat|nested] 2+ messages in thread
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