84 lines
2.8 KiB
Diff
84 lines
2.8 KiB
Diff
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From a4c19259fca5af558fb27d8fa98f2ad4a3689d56 Mon Sep 17 00:00:00 2001
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From: Olivier Fourdan <ofourdan@redhat.com>
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Date: Mon, 20 Jan 2025 16:54:30 +0100
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Subject: [PATCH xserver 11/13] sync: Check values before applying changes
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In SyncInitTrigger(), we would set the CheckTrigger function before
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validating the counter value.
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As a result, if the counter value overflowed, we would leave the
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function SyncInitTrigger() with the CheckTrigger applied but without
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updating the trigger object.
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To avoid that issue, move the portion of code checking for the trigger
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check value before updating the CheckTrigger function.
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Related to CVE-2025-26601, ZDI-CAN-25870
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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 f52cea2f93a0c891494eb3334894442a92368030)
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Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1831>
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---
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Xext/sync.c | 36 ++++++++++++++++++------------------
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1 file changed, 18 insertions(+), 18 deletions(-)
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diff --git a/Xext/sync.c b/Xext/sync.c
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index e55295904..66a52283d 100644
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--- a/Xext/sync.c
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+++ b/Xext/sync.c
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@@ -350,6 +350,24 @@ SyncInitTrigger(ClientPtr client, SyncTrigger * pTrigger, XID syncObject,
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}
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}
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+ if (changes & (XSyncCAValueType | XSyncCAValue)) {
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+ if (pTrigger->value_type == XSyncAbsolute)
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+ pTrigger->test_value = pTrigger->wait_value;
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+ else { /* relative */
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+ Bool overflow;
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+
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+ if (pCounter == NULL)
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+ return BadMatch;
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+
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+ overflow = checked_int64_add(&pTrigger->test_value,
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+ pCounter->value, pTrigger->wait_value);
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+ if (overflow) {
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+ client->errorValue = pTrigger->wait_value >> 32;
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+ return BadValue;
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+ }
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+ }
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+ }
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+
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if (changes & XSyncCATestType) {
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if (pSync && SYNC_FENCE == pSync->type) {
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@@ -378,24 +396,6 @@ SyncInitTrigger(ClientPtr client, SyncTrigger * pTrigger, XID syncObject,
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}
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}
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- if (changes & (XSyncCAValueType | XSyncCAValue)) {
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- if (pTrigger->value_type == XSyncAbsolute)
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- pTrigger->test_value = pTrigger->wait_value;
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- else { /* relative */
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- Bool overflow;
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-
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- if (pCounter == NULL)
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- return BadMatch;
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-
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- overflow = checked_int64_add(&pTrigger->test_value,
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- pCounter->value, pTrigger->wait_value);
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- if (overflow) {
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- client->errorValue = pTrigger->wait_value >> 32;
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- return BadValue;
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- }
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- }
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- }
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-
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if (changes & XSyncCACounter) {
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if (pSync != pTrigger->pSync) { /* new counter for trigger */
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SyncDeleteTriggerFromSyncObject(pTrigger);
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--
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2.48.1
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