From 3ec7685d0202787cc556f7c4c64a4d44baf78709 Mon Sep 17 00:00:00 2001
From: Fiona Ebner <f.ebner@proxmox.com>
Date: Wed, 6 Sep 2023 15:09:22 +0200
Subject: [PATCH] tests/qtest: ahci-test: add test exposing reset issue with
 pending callback (Fix CVE-2023-5088)
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Before commit "hw/ide: reset: cancel async DMA operation before
resetting state", this test would fail, because a reset with a
pending write operation would lead to an unsolicited write to the
first sector of the disk.

The test writes a pattern to the beginning of the disk and verifies
that it is still intact after a reset with a pending operation. It
also checks that the pending operation actually completes correctly.

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Message-ID: <20230906130922.142845-2-f.ebner@proxmox.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 tests/ahci-test.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 85 insertions(+), 1 deletion(-)

diff --git a/tests/ahci-test.c b/tests/ahci-test.c
index 086811e602..659623fc22 100644
--- a/tests/ahci-test.c
+++ b/tests/ahci-test.c
@@ -1426,6 +1426,89 @@ static void test_reset(void)
     ahci_shutdown(ahci);
 }
 
+static void test_reset_pending_callback(void)
+{
+    AHCIQState *ahci;
+    AHCICommand *cmd;
+    uint8_t port;
+    uint64_t ptr1;
+    uint64_t ptr2;
+
+    int bufsize = 4 * 1024;
+    int speed = bufsize + (bufsize / 2);
+    int offset1 = 0;
+    int offset2 = bufsize / AHCI_SECTOR_SIZE;
+
+    g_autofree unsigned char *tx1 = g_malloc(bufsize);
+    g_autofree unsigned char *tx2 = g_malloc(bufsize);
+    g_autofree unsigned char *rx1 = g_malloc0(bufsize);
+    g_autofree unsigned char *rx2 = g_malloc0(bufsize);
+
+    /* Uses throttling to make test independent of specific environment. */
+    ahci = ahci_boot_and_enable("-drive if=none,id=drive0,file=%s,"
+                                "cache=writeback,format=%s,"
+                                "throttling.bps-write=%d "
+                                "-M q35 "
+                                "-device ide-hd,drive=drive0 ",
+                                tmp_path, imgfmt, speed);
+
+    port = ahci_port_select(ahci);
+    ahci_port_clear(ahci, port);
+
+    ptr1 = ahci_alloc(ahci, bufsize);
+    ptr2 = ahci_alloc(ahci, bufsize);
+
+    g_assert(ptr1 && ptr2);
+
+    /* Need two different patterns. */
+    do {
+        generate_pattern(tx1, bufsize, AHCI_SECTOR_SIZE);
+        generate_pattern(tx2, bufsize, AHCI_SECTOR_SIZE);
+    } while (memcmp(tx1, tx2, bufsize) == 0);
+
+    qtest_bufwrite(ahci->parent->qts, ptr1, tx1, bufsize);
+    qtest_bufwrite(ahci->parent->qts, ptr2, tx2, bufsize);
+
+    /* Write to beginning of disk to check it wasn't overwritten later. */
+    ahci_guest_io(ahci, port, CMD_WRITE_DMA_EXT, ptr1, bufsize, offset1);
+
+    /* Issue asynchronously to get a pending callback during reset. */
+    cmd = ahci_command_create(CMD_WRITE_DMA_EXT);
+    ahci_command_adjust(cmd, offset2, ptr2, bufsize, 0);
+    ahci_command_commit(ahci, cmd, port);
+    ahci_command_issue_async(ahci, cmd);
+
+    ahci_set(ahci, AHCI_GHC, AHCI_GHC_HR);
+
+    ahci_command_free(cmd);
+
+    /* Wait for throttled write to finish. */
+    sleep(1);
+
+    /* Start again. */
+    ahci_clean_mem(ahci);
+    ahci_pci_enable(ahci);
+    ahci_hba_enable(ahci);
+    port = ahci_port_select(ahci);
+    ahci_port_clear(ahci, port);
+
+    /* Read and verify. */
+    ahci_guest_io(ahci, port, CMD_READ_DMA_EXT, ptr1, bufsize, offset1);
+    qtest_bufread(ahci->parent->qts, ptr1, rx1, bufsize);
+    g_assert_cmphex(memcmp(tx1, rx1, bufsize), ==, 0);
+
+    ahci_guest_io(ahci, port, CMD_READ_DMA_EXT, ptr2, bufsize, offset2);
+    qtest_bufread(ahci->parent->qts, ptr2, rx2, bufsize);
+    g_assert_cmphex(memcmp(tx2, rx2, bufsize), ==, 0);
+
+    ahci_free(ahci, ptr1);
+    ahci_free(ahci, ptr2);
+
+    ahci_clean_mem(ahci);
+
+    ahci_shutdown(ahci);
+}
+
 static void test_ncq_simple(void)
 {
     AHCIQState *ahci;
@@ -1929,7 +2012,8 @@ int main(int argc, char **argv)
     qtest_add_func("/ahci/migrate/dma/halted", test_migrate_halted_dma);
 
     qtest_add_func("/ahci/max", test_max);
-    qtest_add_func("/ahci/reset", test_reset);
+    qtest_add_func("/ahci/reset/simple", test_reset);
+    qtest_add_func("/ahci/reset/pending_callback", test_reset_pending_callback);
 
     qtest_add_func("/ahci/io/ncq/simple", test_ncq_simple);
     qtest_add_func("/ahci/migrate/ncq/simple", test_migrate_ncq);
-- 
2.41.0.windows.1

