diff -Nru libvirt-10.0.0/debian/changelog libvirt-10.0.0/debian/changelog --- libvirt-10.0.0/debian/changelog 2024-04-18 15:42:32.000000000 +0000 +++ libvirt-10.0.0/debian/changelog 2024-05-06 13:12:37.000000000 +0000 @@ -1,3 +1,12 @@ +libvirt (10.0.0-2ubuntu8.2) noble-security; urgency=medium + + * SECURITY UPDATE: stack use-after-free in virNetClientIOEventLoop() + - debian/patches/CVE-2024-4418.patch: ensure temporary GSource is + removed from client event loop in src/rpc/virnetclient.c. + - CVE-2024-4418 + + -- Marc Deslauriers Mon, 06 May 2024 09:12:37 -0400 + libvirt (10.0.0-2ubuntu8.1) noble-security; urgency=medium * SECURITY UPDATE: off-by-one in udevListInterfacesByStatus() diff -Nru libvirt-10.0.0/debian/patches/CVE-2024-4418.patch libvirt-10.0.0/debian/patches/CVE-2024-4418.patch --- libvirt-10.0.0/debian/patches/CVE-2024-4418.patch 1970-01-01 00:00:00.000000000 +0000 +++ libvirt-10.0.0/debian/patches/CVE-2024-4418.patch 2024-05-06 13:12:07.000000000 +0000 @@ -0,0 +1,99 @@ +From 8074d64dc2eca846d6a61efe1a9b7428a0ce1dd1 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= +Date: Tue, 30 Apr 2024 11:51:15 +0100 +Subject: [PATCH] rpc: ensure temporary GSource is removed from client event + loop +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Users are seeing periodic segfaults from libvirt client apps, +especially thread heavy ones like virt-manager. A typical +stack trace would end up in the virNetClientIOEventFD method, +with illegal access to stale stack data. eg + +==238721==ERROR: AddressSanitizer: stack-use-after-return on address 0x75cd18709788 at pc 0x75cd3111f907 bp 0x75cd181ff550 sp 0x75cd181ff548 +WRITE of size 4 at 0x75cd18709788 thread T11 + #0 0x75cd3111f906 in virNetClientIOEventFD /usr/src/debug/libvirt/libvirt-10.2.0/build/../src/rpc/virnetclient.c:1634:15 + #1 0x75cd3210d198 (/usr/lib/libglib-2.0.so.0+0x5a198) (BuildId: 0a2311dfbbc6c215dc36f4b6bdd2b4b6fbae55a2) + #2 0x75cd3216c3be (/usr/lib/libglib-2.0.so.0+0xb93be) (BuildId: 0a2311dfbbc6c215dc36f4b6bdd2b4b6fbae55a2) + #3 0x75cd3210ddc6 in g_main_loop_run (/usr/lib/libglib-2.0.so.0+0x5adc6) (BuildId: 0a2311dfbbc6c215dc36f4b6bdd2b4b6fbae55a2) + #4 0x75cd3111a47c in virNetClientIOEventLoop /usr/src/debug/libvirt/libvirt-10.2.0/build/../src/rpc/virnetclient.c:1722:9 + #5 0x75cd3111a47c in virNetClientIO /usr/src/debug/libvirt/libvirt-10.2.0/build/../src/rpc/virnetclient.c:2002:10 + #6 0x75cd3111a47c in virNetClientSendInternal /usr/src/debug/libvirt/libvirt-10.2.0/build/../src/rpc/virnetclient.c:2170:11 + #7 0x75cd311198a8 in virNetClientSendWithReply /usr/src/debug/libvirt/libvirt-10.2.0/build/../src/rpc/virnetclient.c:2198:11 + #8 0x75cd31111653 in virNetClientProgramCall /usr/src/debug/libvirt/libvirt-10.2.0/build/../src/rpc/virnetclientprogram.c:318:9 + #9 0x75cd31241c8f in callFull /usr/src/debug/libvirt/libvirt-10.2.0/build/../src/remote/remote_driver.c:6054:10 + #10 0x75cd31241c8f in call /usr/src/debug/libvirt/libvirt-10.2.0/build/../src/remote/remote_driver.c:6076:12 + #11 0x75cd31241c8f in remoteNetworkGetXMLDesc /usr/src/debug/libvirt/libvirt-10.2.0/build/src/remote/remote_client_bodies.h:5959:9 + #12 0x75cd31410ff7 in virNetworkGetXMLDesc /usr/src/debug/libvirt/libvirt-10.2.0/build/../src/libvirt-network.c:952:15 + +The root cause is a bad assumption in the virNetClientIOEventLoop +method. This method is run by whichever thread currently owns the +buck, and is responsible for handling I/O. Inside a for(;;) loop, +this method creates a temporary GSource, adds it to the event loop +and runs g_main_loop_run(). When I/O is ready, the GSource callback +(virNetClientIOEventFD) will fire and call g_main_loop_quit(), and +return G_SOURCE_REMOVE which results in the temporary GSource being +destroyed. A g_autoptr() will then remove the last reference. + +What was overlooked, is that a second thread can come along and +while it can't enter virNetClientIOEventLoop, it will register an +idle source that uses virNetClientIOWakeup to interrupt the +original thread's 'g_main_loop_run' call. When this happens the +virNetClientIOEventFD callback never runs, and so the temporary +GSource is not destroyed. The g_autoptr() will remove a reference, +but by virtue of still being attached to the event context, there +is an extra reference held causing GSource to be leaked. The +next time 'g_main_loop_run' is called, the original GSource will +trigger its callback, and access data that was allocated on the +stack by the previous thread, and likely SEGV. + +To solve this, the thread calling 'g_main_loop_run' must call +g_source_destroy, immediately upon return, to guarantee that +the temporary GSource is removed. + +CVE-2024-4418 +Reviewed-by: Ján Tomko +Reported-by: Martin Shirokov +Tested-by: Martin Shirokov +Signed-off-by: Daniel P. Berrangé +--- + src/rpc/virnetclient.c | 14 +++++++++++++- + 1 file changed, 13 insertions(+), 1 deletion(-) + +diff --git a/src/rpc/virnetclient.c b/src/rpc/virnetclient.c +index 68098b1c8d..147b0d661a 100644 +--- a/src/rpc/virnetclient.c ++++ b/src/rpc/virnetclient.c +@@ -1657,7 +1657,7 @@ static int virNetClientIOEventLoop(virNetClient *client, + #endif /* !WIN32 */ + int timeout = -1; + virNetMessage *msg = NULL; +- g_autoptr(GSource) G_GNUC_UNUSED source = NULL; ++ g_autoptr(GSource) source = NULL; + GIOCondition ev = 0; + struct virNetClientIOEventData data = { + .client = client, +@@ -1721,6 +1721,18 @@ static int virNetClientIOEventLoop(virNetClient *client, + + g_main_loop_run(client->eventLoop); + ++ /* ++ * If virNetClientIOEventFD ran, this GSource will already be ++ * destroyed due to G_SOURCE_REMOVE. It is harmless to re-destroy ++ * it, since we still own a reference. ++ * ++ * If virNetClientIOWakeup ran, it will have interrupted the ++ * g_main_loop_run call, before virNetClientIOEventFD could ++ * run, and thus the GSource is still registered, and we need ++ * to destroy it since it is referencing stack memory for 'data' ++ */ ++ g_source_destroy(source); ++ + #ifndef WIN32 + ignore_value(pthread_sigmask(SIG_SETMASK, &oldmask, NULL)); + #endif /* !WIN32 */ +-- +GitLab + diff -Nru libvirt-10.0.0/debian/patches/series libvirt-10.0.0/debian/patches/series --- libvirt-10.0.0/debian/patches/series 2024-04-18 15:42:26.000000000 +0000 +++ libvirt-10.0.0/debian/patches/series 2024-05-06 13:12:07.000000000 +0000 @@ -46,3 +46,4 @@ ubuntu-aa/lp-1815910-allow-vhost-hotplug.patch CVE-2024-1441.patch CVE-2024-2494.patch +CVE-2024-4418.patch