From d5829eac5f7cfff89c6d1cf11717eee97cf030d0 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 5 Sep 2012 17:09:15 +0200 Subject: [PATCH] target: fix use-after-free with PSCSI sense data The pointer to the sense buffer is fetched by transport_get_sense_data, but this is called by target_complete_ok_work long after pscsi_req_done has freed the struct that contains it. Pass instead the fabric's sense buffer to transport_complete, and copy the data to it directly in transport_complete. Setting SCF_TRANSPORT_TASK_SENSE also becomes a duty of transport_complete. Signed-off-by: Paolo Bonzini Cc: stable@vger.kernel.org Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_pscsi.c | 21 +++++---------- drivers/target/target_core_transport.c | 36 ++++++++++---------------- include/target/target_core_backend.h | 4 ++- 3 files changed, 24 insertions(+), 37 deletions(-) diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c index 5552fa7426bc..5f7151d90344 100644 --- a/drivers/target/target_core_pscsi.c +++ b/drivers/target/target_core_pscsi.c @@ -667,7 +667,8 @@ static void pscsi_free_device(void *p) kfree(pdv); } -static int pscsi_transport_complete(struct se_cmd *cmd, struct scatterlist *sg) +static void pscsi_transport_complete(struct se_cmd *cmd, struct scatterlist *sg, + unsigned char *sense_buffer) { struct pscsi_dev_virt *pdv = cmd->se_dev->dev_ptr; struct scsi_device *sd = pdv->pdv_sd; @@ -679,7 +680,7 @@ static int pscsi_transport_complete(struct se_cmd *cmd, struct scatterlist *sg) * not been allocated because TCM is handling the emulation directly. */ if (!pt) - return 0; + return; cdb = &pt->pscsi_cdb[0]; result = pt->pscsi_result; @@ -750,10 +751,10 @@ after_mode_sense: } after_mode_select: - if (status_byte(result) & CHECK_CONDITION) - return 1; - - return 0; + if (sense_buffer && (status_byte(result) & CHECK_CONDITION)) { + memcpy(sense_buffer, pt->pscsi_sense, TRANSPORT_SENSE_BUFFER); + cmd->se_cmd_flags |= SCF_TRANSPORT_TASK_SENSE; + } } enum { @@ -1184,13 +1185,6 @@ fail: return -ENOMEM; } -static unsigned char *pscsi_get_sense_buffer(struct se_cmd *cmd) -{ - struct pscsi_plugin_task *pt = cmd->priv; - - return pt->pscsi_sense; -} - /* pscsi_get_device_rev(): * * @@ -1273,7 +1267,6 @@ static struct se_subsystem_api pscsi_template = { .check_configfs_dev_params = pscsi_check_configfs_dev_params, .set_configfs_dev_params = pscsi_set_configfs_dev_params, .show_configfs_dev_params = pscsi_show_configfs_dev_params, - .get_sense_buffer = pscsi_get_sense_buffer, .get_device_rev = pscsi_get_device_rev, .get_device_type = pscsi_get_device_type, .get_blocks = pscsi_get_blocks, diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 040f05fde4d6..8a29e3fd0195 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -568,38 +568,31 @@ static void target_complete_failure_work(struct work_struct *work) } /* - * Used to obtain Sense Data from underlying Linux/SCSI struct scsi_cmnd + * Used when asking transport to copy Sense Data from the underlying + * Linux/SCSI struct scsi_cmnd */ -static void transport_get_sense_data(struct se_cmd *cmd) +static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd) { - unsigned char *buffer = cmd->sense_buffer, *sense_buffer = NULL; + unsigned char *buffer = cmd->sense_buffer; struct se_device *dev = cmd->se_dev; - unsigned long flags; u32 offset = 0; WARN_ON(!cmd->se_lun); if (!dev) - return; + return NULL; - spin_lock_irqsave(&cmd->t_state_lock, flags); - if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) { - spin_unlock_irqrestore(&cmd->t_state_lock, flags); - return; - } - - sense_buffer = dev->transport->get_sense_buffer(cmd); - spin_unlock_irqrestore(&cmd->t_state_lock, flags); + if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) + return NULL; offset = cmd->se_tfo->set_fabric_sense_len(cmd, TRANSPORT_SENSE_BUFFER); - memcpy(&buffer[offset], sense_buffer, TRANSPORT_SENSE_BUFFER); - /* Automatically padded */ cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER + offset; - pr_debug("HBA_[%u]_PLUG[%s]: Set SAM STATUS: 0x%02x and sense\n", + pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n", dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status); + return &buffer[offset]; } void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status) @@ -615,11 +608,11 @@ void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status) cmd->transport_state &= ~CMD_T_BUSY; if (dev && dev->transport->transport_complete) { - if (dev->transport->transport_complete(cmd, - cmd->t_data_sg) != 0) { - cmd->se_cmd_flags |= SCF_TRANSPORT_TASK_SENSE; + dev->transport->transport_complete(cmd, + cmd->t_data_sg, + transport_get_sense_buffer(cmd)); + if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) success = 1; - } } /* @@ -1987,12 +1980,11 @@ static void target_complete_ok_work(struct work_struct *work) schedule_work(&cmd->se_dev->qf_work_queue); /* - * Check if we need to retrieve a sense buffer from + * Check if we need to send a sense buffer from * the struct se_cmd in question. */ if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) { WARN_ON(!cmd->scsi_status); - transport_get_sense_data(cmd); ret = transport_send_check_condition_and_sense( cmd, 0, 1); if (ret == -EAGAIN || ret == -ENOMEM) diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h index f1405d335a96..941c84bf1065 100644 --- a/include/target/target_core_backend.h +++ b/include/target/target_core_backend.h @@ -23,7 +23,9 @@ struct se_subsystem_api { struct se_device *(*create_virtdevice)(struct se_hba *, struct se_subsystem_dev *, void *); void (*free_device)(void *); - int (*transport_complete)(struct se_cmd *cmd, struct scatterlist *); + void (*transport_complete)(struct se_cmd *cmd, + struct scatterlist *, + unsigned char *); int (*parse_cdb)(struct se_cmd *cmd); ssize_t (*check_configfs_dev_params)(struct se_hba *,