xserver-xorg: Fix for CVE-2025-49178

Upstream-Status: Backport from https://gitlab.freedesktop.org/xorg/xserver/-/commit/d55c54cecb5e83eaa2d56bed5cc4461f9ba318c2

(From OE-Core rev: 8d29231af51de235b99be0eeb71dfab41d67589d)

Signed-off-by: Vijay Anusuri <vanusuri@mvista.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

2 files changed, 50 insertions, 0 deletions

diff --git a/meta/recipes-graphics/xorg-xserver/xserver-xorg/CVE-2025-49178.patch b/meta/recipes-graphics/xorg-xserver/xserver-xorg/CVE-2025-49178.patch
new file mode 100644
index 0000000000..ce3e2f415f
--- /dev/null
+++ b/meta/recipes-graphics/xorg-xserver/xserver-xorg/CVE-2025-49178.patch
@@ -0,0 +1,49 @@
+From d55c54cecb5e83eaa2d56bed5cc4461f9ba318c2 Mon Sep 17 00:00:00 2001
+From: Olivier Fourdan <ofourdan@redhat.com>
+Date: Mon, 28 Apr 2025 10:46:03 +0200
+Subject: [PATCH] os: Account for bytes to ignore when sharing input buffer
+
+When reading requests from the clients, the input buffer might be shared
+and used between different clients.
+
+If a given client sends a full request with non-zero bytes to ignore,
+the bytes to ignore may still be non-zero even though the request is
+full, in which case the buffer could be shared with another client who's
+request will not be processed because of those bytes to ignore, leading
+to a possible hang of the other client request.
+
+To avoid the issue, make sure we have zero bytes to ignore left in the
+input request when sharing the input buffer with another client.
+
+CVE-2025-49178
+
+This issue was discovered by Nils Emmerich <nemmerich@ernw.de> and
+reported by Julian Suleder via ERNW Vulnerability Disclosure.
+
+Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
+Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
+Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2024>
+
+Upstream-Status: Backport [https://gitlab.freedesktop.org/xorg/xserver/-/commit/d55c54cecb5e83eaa2d56bed5cc4461f9ba318c2]
+CVE: CVE-2025-49178
+Signed-off-by: Vijay Anusuri <vanusuri@mvista.com>
+---
+ os/io.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/os/io.c b/os/io.c
+index 3e39c10e6f..e7b76b9cea 100644
+--- a/os/io.c
++++ b/os/io.c
+@@ -441,7 +441,7 @@ ReadRequestFromClient(ClientPtr client)
+      */
+ 
+     gotnow -= needed;
+-    if (!gotnow)
++    if (!gotnow && !oci->ignoreBytes)
+         AvailableInput = oc;
+     if (move_header) {
+         if (client->req_len < bytes_to_int32(sizeof(xBigReq) - sizeof(xReq))) {
+-- 
+GitLab
+
diff --git a/meta/recipes-graphics/xorg-xserver/xserver-xorg_21.1.8.bb b/meta/recipes-graphics/xorg-xserver/xserver-xorg_21.1.8.bb
index 1fceec89f7..67e146bf97 100644
--- a/meta/recipes-graphics/xorg-xserver/xserver-xorg_21.1.8.bb
+++ b/meta/recipes-graphics/xorg-xserver/xserver-xorg_21.1.8.bb
@@ -40,6 +40,7 @@ SRC_URI += "file://0001-xf86pciBus.c-use-Intel-ddx-only-for-pre-gen4-hardwar.pat
            file://CVE-2025-49176-1.patch \
            file://CVE-2025-49176-2.patch \
            file://CVE-2025-49177.patch \
+           file://CVE-2025-49178.patch \
            "
 SRC_URI[sha256sum] = "38aadb735650c8024ee25211c190bf8aad844c5f59632761ab1ef4c4d5aeb152"