Commit 4367a20c authored by Mauro Matteo Cascella's avatar Mauro Matteo Cascella Committed by Paolo Bonzini
Browse files

scsi/lsi53c895a: really fix use-after-free in lsi_do_msgout (CVE-2022-0216)

Set current_req to NULL, not current_req->req, 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.

Thanks to Alexander Bulekov for providing a reproducer.

Fixes: CVE-2022-0216
Resolves: #972


Signed-off-by: Mauro Matteo Cascella's avatarMauro Matteo Cascella <mcascell@redhat.com>
Tested-by: Alexander Bulekov's avatarAlexander Bulekov <alxndr@bu.edu>
Message-Id: <20220711123316.421279-1-mcascell@redhat.com>
Signed-off-by: Paolo Bonzini's avatarPaolo Bonzini <pbonzini@redhat.com>
parent 8e3d85d3
......@@ -1030,7 +1030,7 @@ static void lsi_do_msgout(LSIState *s)
trace_lsi_do_msgout_abort(current_tag);
if (current_req && current_req->req) {
scsi_req_cancel(current_req->req);
current_req->req = NULL;
current_req = NULL;
}
lsi_disconnect(s);
break;
......@@ -1056,6 +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
......
......@@ -8,6 +8,79 @@
#include "qemu/osdep.h"
#include "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
......@@ -44,5 +117,8 @@ int main(int argc, char **argv)
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();
}
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