From 754371b1f2f872156dda4cb4aa16b510c142c381 Mon Sep 17 00:00:00 2001 From: Mauro Matteo Cascella Date: Tue, 5 Jul 2022 22:05:43 +0200 Subject: [PATCH] scsi/lsi53c895a: fix use-after-free in lsi_do_msgout (CVE-2022-0216) Set current_req to NULL to prevent reusing a free'd buffer in case of repeated SCSI cancel requests. Also apply the fix to CLEAR QUEUE and BUS DEVICE RESET messages as well, since they also cancel the request. Fixes: CVE-2022-0216 Resolves: https://gitlab.com/qemu-project/qemu/-/issues/972 Signed-off-by: Mauro Matteo Cascella Reviewed-by: Thomas Huth Message-Id: <20220705200543.2366809-1-mcascell@redhat.com> Signed-off-by: Paolo Bonzini --- hw/scsi/lsi53c895a.c | 4 +- tests/qtest/fuzz-lsi53c895a-test.c | 75 ++++++++++++++++++++++++++++++ 2 files changed, 78 insertions(+), 1 deletion(-) diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c index c8773f73f7..ad5f5e5f39 100644 --- a/hw/scsi/lsi53c895a.c +++ b/hw/scsi/lsi53c895a.c @@ -1028,8 +1028,9 @@ static void lsi_do_msgout(LSIState *s) case 0x0d: /* The ABORT TAG message clears the current I/O process only. */ trace_lsi_do_msgout_abort(current_tag); - if (current_req) { + if (current_req && current_req->req) { scsi_req_cancel(current_req->req); + current_req = NULL; } lsi_disconnect(s); break; @@ -1055,6 +1056,7 @@ static void lsi_do_msgout(LSIState *s) /* clear the current I/O process */ if (s->current) { scsi_req_cancel(s->current->req); + current_req = NULL; } /* As the current implemented devices scsi_disk and scsi_generic diff --git a/tests/qtest/fuzz-lsi53c895a-test.c b/tests/qtest/fuzz-lsi53c895a-test.c index ba5d468970..0f968024c8 100644 --- a/tests/qtest/fuzz-lsi53c895a-test.c +++ b/tests/qtest/fuzz-lsi53c895a-test.c @@ -8,6 +8,79 @@ #include "qemu/osdep.h" #include "libqos/libqtest.h" +/* + * This used to trigger a UAF in lsi_do_msgout() + * https://gitlab.com/qemu-project/qemu/-/issues/972 + */ +static void test_lsi_do_msgout_cancel_req(void) +{ + QTestState *s; + + if (sizeof(void *) == 4) { + g_test_skip("memory size too big for 32-bit build"); + return; + } + + s = qtest_init("-M q35 -m 4G -display none -nodefaults " + "-device lsi53c895a,id=scsi " + "-device scsi-hd,drive=disk0 " + "-drive file=null-co://,id=disk0,if=none,format=raw"); + + qtest_outl(s, 0xcf8, 0x80000810); + qtest_outl(s, 0xcf8, 0xc000); + qtest_outl(s, 0xcf8, 0x80000810); + qtest_outw(s, 0xcfc, 0x7); + qtest_outl(s, 0xcf8, 0x80000810); + qtest_outl(s, 0xcfc, 0xc000); + qtest_outl(s, 0xcf8, 0x80000804); + qtest_outw(s, 0xcfc, 0x05); + qtest_writeb(s, 0x69736c10, 0x08); + qtest_writeb(s, 0x69736c13, 0x58); + qtest_writeb(s, 0x69736c1a, 0x01); + qtest_writeb(s, 0x69736c1b, 0x06); + qtest_writeb(s, 0x69736c22, 0x01); + qtest_writeb(s, 0x69736c23, 0x07); + qtest_writeb(s, 0x69736c2b, 0x02); + qtest_writeb(s, 0x69736c48, 0x08); + qtest_writeb(s, 0x69736c4b, 0x58); + qtest_writeb(s, 0x69736c52, 0x04); + qtest_writeb(s, 0x69736c53, 0x06); + qtest_writeb(s, 0x69736c5b, 0x02); + qtest_outl(s, 0xc02d, 0x697300); + qtest_writeb(s, 0x5a554662, 0x01); + qtest_writeb(s, 0x5a554663, 0x07); + qtest_writeb(s, 0x5a55466a, 0x10); + qtest_writeb(s, 0x5a55466b, 0x22); + qtest_writeb(s, 0x5a55466c, 0x5a); + qtest_writeb(s, 0x5a55466d, 0x5a); + qtest_writeb(s, 0x5a55466e, 0x34); + qtest_writeb(s, 0x5a55466f, 0x5a); + qtest_writeb(s, 0x5a345a5a, 0x77); + qtest_writeb(s, 0x5a345a5b, 0x55); + qtest_writeb(s, 0x5a345a5c, 0x51); + qtest_writeb(s, 0x5a345a5d, 0x27); + qtest_writeb(s, 0x27515577, 0x41); + qtest_outl(s, 0xc02d, 0x5a5500); + qtest_writeb(s, 0x364001d0, 0x08); + qtest_writeb(s, 0x364001d3, 0x58); + qtest_writeb(s, 0x364001da, 0x01); + qtest_writeb(s, 0x364001db, 0x26); + qtest_writeb(s, 0x364001dc, 0x0d); + qtest_writeb(s, 0x364001dd, 0xae); + qtest_writeb(s, 0x364001de, 0x41); + qtest_writeb(s, 0x364001df, 0x5a); + qtest_writeb(s, 0x5a41ae0d, 0xf8); + qtest_writeb(s, 0x5a41ae0e, 0x36); + qtest_writeb(s, 0x5a41ae0f, 0xd7); + qtest_writeb(s, 0x5a41ae10, 0x36); + qtest_writeb(s, 0x36d736f8, 0x0c); + qtest_writeb(s, 0x36d736f9, 0x80); + qtest_writeb(s, 0x36d736fa, 0x0d); + qtest_outl(s, 0xc02d, 0x364000); + + qtest_quit(s); +} + /* * This used to trigger the assert in lsi_do_dma() * https://bugs.launchpad.net/qemu/+bug/697510 @@ -46,6 +119,8 @@ int main(int argc, char **argv) if (strcmp(arch, "i386") == 0 || strcmp(arch, "x86_64") == 0) { qtest_add_func("fuzz/lsi53c895a/lsi_do_dma_empty_queue", test_lsi_do_dma_empty_queue); + qtest_add_func("fuzz/lsi53c895a/lsi_do_msgout_cancel_req", + test_lsi_do_msgout_cancel_req); } return g_test_run(); -- 2.37.0.rc2