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From 96798fc1967491c80a4d0c8d9e0a80586cb2152b Mon Sep 17 00:00:00 2001
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From: Alan Coopersmith <alan.coopersmith@oracle.com>
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Date: Fri, 22 Mar 2024 18:51:45 -0700
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Subject: [PATCH 1/4] Xi: ProcXIGetSelectedEvents needs to use unswapped length
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 to send reply
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CVE-2024-31080
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Reported-by: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=69762
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Fixes: 53e821ab4 ("Xi: add request processing for XIGetSelectedEvents.")
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Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
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Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1463>
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---
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 Xi/xiselectev.c | 5 ++++-
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 1 file changed, 4 insertions(+), 1 deletion(-)
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diff --git a/Xi/xiselectev.c b/Xi/xiselectev.c
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index edcb8a0d3..ac1494987 100644
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--- a/Xi/xiselectev.c
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+++ b/Xi/xiselectev.c
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@@ -349,6 +349,7 @@ ProcXIGetSelectedEvents(ClientPtr client)
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     InputClientsPtr others = NULL;
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     xXIEventMask *evmask = NULL;
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     DeviceIntPtr dev;
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+    uint32_t length;
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     REQUEST(xXIGetSelectedEventsReq);
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     REQUEST_SIZE_MATCH(xXIGetSelectedEventsReq);
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@@ -418,10 +419,12 @@ ProcXIGetSelectedEvents(ClientPtr client)
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         }
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     }
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+    /* save the value before SRepXIGetSelectedEvents swaps it */
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+    length = reply.length;
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     WriteReplyToClient(client, sizeof(xXIGetSelectedEventsReply), &reply);
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     if (reply.num_masks)
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-        WriteToClient(client, reply.length * 4, buffer);
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+        WriteToClient(client, length * 4, buffer);
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     free(buffer);
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     return Success;
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-- 
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2.44.0
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