commit fe9d8927e265fd723a6dc87cd6d220f4677dbe1f
author John Millikin <john@john-millikin.com> Wed Aug 17 14:34:58 2022 +0900
committer Paolo Bonzini <pbonzini@redhat.com> Thu Sep 01 07:42:37 2022 +0200
tree 0e2d306704d29e6a06cc10b7a320afcbb31279a1
parent c6e51f1bb28ed762d2039c063cbb71a8ad29762d

scsi: Add buf_len parameter to scsi_req_new()

When a SCSI command is received from the guest, the CDB length implied
by the first byte might exceed the number of bytes the guest sent. In
this case scsi_req_new() will read uninitialized data, causing
unpredictable behavior.

Adds the buf_len parameter to scsi_req_new() and plumbs it through the
call stack.

Signed-off-by: John Millikin <john@john-millikin.com>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1127
Message-Id: <20220817053458.698416-1-john@john-millikin.com>
[Fill in correct length for adapters other than ESP. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/scsi/megasas.c

diff --git a/hw/scsi/megasas.c b/hw/scsi/megasas.c
index d5dfb41..7082456 100644
--- a/hw/scsi/megasas.c
+++ b/hw/scsi/megasas.c
@@ -1062,7 +1062,7 @@
         info->inquiry_data[0] = 0x7f; /* Force PQual 0x3, PType 0x1f */
         info->vpd_page83[0] = 0x7f;
         megasas_setup_inquiry(cmdbuf, 0, sizeof(info->inquiry_data));
-        cmd->req = scsi_req_new(sdev, cmd->index, lun, cmdbuf, cmd);
+        cmd->req = scsi_req_new(sdev, cmd->index, lun, cmdbuf, sizeof(cmdbuf), cmd);
         if (!cmd->req) {
             trace_megasas_dcmd_req_alloc_failed(cmd->index,
                                                 "PD get info std inquiry");
@@ -1080,7 +1080,7 @@
         return MFI_STAT_INVALID_STATUS;
     } else if (info->inquiry_data[0] != 0x7f && info->vpd_page83[0] == 0x7f) {
         megasas_setup_inquiry(cmdbuf, 0x83, sizeof(info->vpd_page83));
-        cmd->req = scsi_req_new(sdev, cmd->index, lun, cmdbuf, cmd);
+        cmd->req = scsi_req_new(sdev, cmd->index, lun, cmdbuf, sizeof(cmdbuf), cmd);
         if (!cmd->req) {
             trace_megasas_dcmd_req_alloc_failed(cmd->index,
                                                 "PD get info vpd inquiry");
@@ -1268,7 +1268,7 @@
         cmd->iov_buf = g_malloc0(dcmd_size);
         info = cmd->iov_buf;
         megasas_setup_inquiry(cdb, 0x83, sizeof(info->vpd_page83));
-        cmd->req = scsi_req_new(sdev, cmd->index, lun, cdb, cmd);
+        cmd->req = scsi_req_new(sdev, cmd->index, lun, cdb, sizeof(cdb), cmd);
         if (!cmd->req) {
             trace_megasas_dcmd_req_alloc_failed(cmd->index,
                                                 "LD get info vpd inquiry");
@@ -1748,7 +1748,7 @@
         return MFI_STAT_SCSI_DONE_WITH_ERROR;
     }
 
-    cmd->req = scsi_req_new(sdev, cmd->index, lun_id, cdb, cmd);
+    cmd->req = scsi_req_new(sdev, cmd->index, lun_id, cdb, cdb_len, cmd);
     if (!cmd->req) {
         trace_megasas_scsi_req_alloc_failed(
                 mfi_frame_desc(frame_cmd), target_id, lun_id);
@@ -1823,7 +1823,7 @@
 
     megasas_encode_lba(cdb, lba_start, lba_count, is_write);
     cmd->req = scsi_req_new(sdev, cmd->index,
-                            lun_id, cdb, cmd);
+                            lun_id, cdb, cdb_len, cmd);
     if (!cmd->req) {
         trace_megasas_scsi_req_alloc_failed(
             mfi_frame_desc(frame_cmd), target_id, lun_id);