From ee760ac80ac1f130138e8eb4eba263a4d48ace51 Mon Sep 17 00:00:00 2001 From: Thomas Huth Date: Mon, 15 Jun 2020 09:26:29 +0200 Subject: [PATCH] hw/scsi/megasas: Fix possible out-of-bounds array access in tracepoints MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Some tracepoints in megasas.c use a guest-controlled value as an index into the mfi_frame_desc[] array. Thus a malicious guest could cause an out-of-bounds error here. Fortunately, the impact is very low since this can only happen when the corresponding tracepoints have been enabled before, but the problem should be fixed anyway with a proper check. Buglink: https://bugs.launchpad.net/qemu/+bug/1882065 Signed-off-by: Thomas Huth Message-Id: <20200615072629.32321-1-thuth@redhat.com> Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Paolo Bonzini --- hw/scsi/megasas.c | 36 +++++++++++++++++++++++------------- 1 file changed, 23 insertions(+), 13 deletions(-) diff --git a/hw/scsi/megasas.c b/hw/scsi/megasas.c index 634af0bbb8..5cfd1bf22e 100644 --- a/hw/scsi/megasas.c +++ b/hw/scsi/megasas.c @@ -54,10 +54,6 @@ #define MEGASAS_FLAG_USE_QUEUE64 1 #define MEGASAS_MASK_USE_QUEUE64 (1 << MEGASAS_FLAG_USE_QUEUE64) -static const char *mfi_frame_desc[] = { - "MFI init", "LD Read", "LD Write", "LD SCSI", "PD SCSI", - "MFI Doorbell", "MFI Abort", "MFI SMP", "MFI Stop"}; - typedef struct MegasasCmd { uint32_t index; uint16_t flags; @@ -183,6 +179,20 @@ static void megasas_frame_set_scsi_status(MegasasState *s, stb_pci_dma(pci, frame + offsetof(struct mfi_frame_header, scsi_status), v); } +static inline const char *mfi_frame_desc(unsigned int cmd) +{ + static const char *mfi_frame_descs[] = { + "MFI init", "LD Read", "LD Write", "LD SCSI", "PD SCSI", + "MFI Doorbell", "MFI Abort", "MFI SMP", "MFI Stop" + }; + + if (cmd < ARRAY_SIZE(mfi_frame_descs)) { + return mfi_frame_descs[cmd]; + } + + return "Unknown"; +} + /* * Context is considered opaque, but the HBA firmware is running * in little endian mode. So convert it to little endian, too. @@ -1670,25 +1680,25 @@ static int megasas_handle_scsi(MegasasState *s, MegasasCmd *cmd, if (is_logical) { if (target_id >= MFI_MAX_LD || lun_id != 0) { trace_megasas_scsi_target_not_present( - mfi_frame_desc[frame_cmd], is_logical, target_id, lun_id); + mfi_frame_desc(frame_cmd), is_logical, target_id, lun_id); return MFI_STAT_DEVICE_NOT_FOUND; } } sdev = scsi_device_find(&s->bus, 0, target_id, lun_id); cmd->iov_size = le32_to_cpu(cmd->frame->header.data_len); - trace_megasas_handle_scsi(mfi_frame_desc[frame_cmd], is_logical, + trace_megasas_handle_scsi(mfi_frame_desc(frame_cmd), is_logical, target_id, lun_id, sdev, cmd->iov_size); if (!sdev || (megasas_is_jbod(s) && is_logical)) { trace_megasas_scsi_target_not_present( - mfi_frame_desc[frame_cmd], is_logical, target_id, lun_id); + mfi_frame_desc(frame_cmd), is_logical, target_id, lun_id); return MFI_STAT_DEVICE_NOT_FOUND; } if (cdb_len > 16) { trace_megasas_scsi_invalid_cdb_len( - mfi_frame_desc[frame_cmd], is_logical, + mfi_frame_desc(frame_cmd), is_logical, target_id, lun_id, cdb_len); megasas_write_sense(cmd, SENSE_CODE(INVALID_OPCODE)); cmd->frame->header.scsi_status = CHECK_CONDITION; @@ -1706,7 +1716,7 @@ static int megasas_handle_scsi(MegasasState *s, MegasasCmd *cmd, cmd->req = scsi_req_new(sdev, cmd->index, lun_id, cdb, cmd); if (!cmd->req) { trace_megasas_scsi_req_alloc_failed( - mfi_frame_desc[frame_cmd], target_id, lun_id); + mfi_frame_desc(frame_cmd), target_id, lun_id); megasas_write_sense(cmd, SENSE_CODE(NO_SENSE)); cmd->frame->header.scsi_status = BUSY; s->event_count++; @@ -1751,17 +1761,17 @@ static int megasas_handle_io(MegasasState *s, MegasasCmd *cmd, int frame_cmd) } trace_megasas_handle_io(cmd->index, - mfi_frame_desc[frame_cmd], target_id, lun_id, + mfi_frame_desc(frame_cmd), target_id, lun_id, (unsigned long)lba_start, (unsigned long)lba_count); if (!sdev) { trace_megasas_io_target_not_present(cmd->index, - mfi_frame_desc[frame_cmd], target_id, lun_id); + mfi_frame_desc(frame_cmd), target_id, lun_id); return MFI_STAT_DEVICE_NOT_FOUND; } if (cdb_len > 16) { trace_megasas_scsi_invalid_cdb_len( - mfi_frame_desc[frame_cmd], 1, target_id, lun_id, cdb_len); + mfi_frame_desc(frame_cmd), 1, target_id, lun_id, cdb_len); megasas_write_sense(cmd, SENSE_CODE(INVALID_OPCODE)); cmd->frame->header.scsi_status = CHECK_CONDITION; s->event_count++; @@ -1781,7 +1791,7 @@ static int megasas_handle_io(MegasasState *s, MegasasCmd *cmd, int frame_cmd) lun_id, cdb, cmd); if (!cmd->req) { trace_megasas_scsi_req_alloc_failed( - mfi_frame_desc[frame_cmd], target_id, lun_id); + mfi_frame_desc(frame_cmd), target_id, lun_id); megasas_write_sense(cmd, SENSE_CODE(NO_SENSE)); cmd->frame->header.scsi_status = BUSY; s->event_count++; -- 2.11.0