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From 94f6fe99d87cf6ba0adadd95c595158c345b7d29 Mon Sep 17 00:00:00 2001 |
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From: Peter Hutterer <peter.hutterer@who-t.net> |
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Date: Tue, 29 Nov 2022 14:53:07 +1000 |
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Subject: [PATCH xserver 5/7] Xext: free the screen saver resource when |
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replacing it |
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|
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This fixes a use-after-free bug: |
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|
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When a client first calls ScreenSaverSetAttributes(), a struct |
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ScreenSaverAttrRec is allocated and added to the client's |
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resources. |
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|
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When the same client calls ScreenSaverSetAttributes() again, a new |
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struct ScreenSaverAttrRec is allocated, replacing the old struct. The |
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old struct was freed but not removed from the clients resources. |
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|
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Later, when the client is destroyed the resource system invokes |
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ScreenSaverFreeAttr and attempts to clean up the already freed struct. |
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|
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Fix this by letting the resource system free the old attrs instead. |
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|
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CVE-2022-46343, ZDI-CAN 19404 |
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|
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This vulnerability was discovered by: |
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Jan-Niklas Sohn working with Trend Micro Zero Day Initiative |
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|
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Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net> |
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Acked-by: Olivier Fourdan <ofourdan@redhat.com> |
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--- |
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Xext/saver.c | 2 +- |
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1 file changed, 1 insertion(+), 1 deletion(-) |
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|
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diff --git a/Xext/saver.c b/Xext/saver.c |
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index f813ba08d1..fd6153c313 100644 |
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--- a/Xext/saver.c |
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+++ b/Xext/saver.c |
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@@ -1051,7 +1051,7 @@ ScreenSaverSetAttributes(ClientPtr client) |
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pVlist++; |
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} |
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if (pPriv->attr) |
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- FreeScreenAttr(pPriv->attr); |
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+ FreeResource(pPriv->attr->resource, AttrType); |
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pPriv->attr = pAttr; |
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pAttr->resource = FakeClientID(client->index); |
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if (!AddResource(pAttr->resource, AttrType, (void *) pAttr)) |
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-- |
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2.38.1 |
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