49 lines
1.6 KiB
Diff
49 lines
1.6 KiB
Diff
From b4f63879f2a5cf0578101591f26471238f944e9c 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 4/7] os: Account for bytes to ignore when sharing
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input 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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(cherry picked from commit d55c54cecb5e83eaa2d56bed5cc4461f9ba318c2)
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Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2025>
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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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diff --git a/os/io.c b/os/io.c
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index de5b3c921..b7f2750b5 100644
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--- a/os/io.c
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+++ b/os/io.c
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@@ -444,7 +444,7 @@ 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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--
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2.49.0
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