43 lines
1.5 KiB
Diff
43 lines
1.5 KiB
Diff
From 247f1622fa8d48783b4ed5d5154791c171f00e18 Mon Sep 17 00:00:00 2001
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From: Olivier Fourdan <ofourdan@redhat.com>
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Date: Mon, 28 Apr 2025 10:46:03 +0200
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Subject: [PATCH xserver] os: Account for bytes to ignore when sharing input
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buffer
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When reading requests from the clients, the input buffer might be shared
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and used between different clients.
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If a given client sends a full request with non-zero bytes to ignore,
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the bytes to ignore may still be non-zero even though the request is
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full, in which case the buffer could be shared with another client who's
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request will not be processed because of those bytes to ignore, leading
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to a possible hang of the other client request.
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To avoid the issue, make sure we have zero bytes to ignore left in the
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input request when sharing the input buffer with another client.
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CVE-2025-49178
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This issue was discovered by Nils Emmerich <nemmerich@ernw.de> and
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reported by Julian Suleder via ERNW Vulnerability Disclosure.
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Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
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Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
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---
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os/io.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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Index: xwayland-24.1.6/os/io.c
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===================================================================
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--- xwayland-24.1.6.orig/os/io.c
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+++ xwayland-24.1.6/os/io.c
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@@ -445,7 +445,7 @@ ReadRequestFromClient(ClientPtr client)
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*/
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gotnow -= needed;
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- if (!gotnow)
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+ if (!gotnow && !oci->ignoreBytes)
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AvailableInput = oc;
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if (move_header) {
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if (client->req_len < bytes_to_int32(sizeof(xBigReq) - sizeof(xReq))) {
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