block: move cmdfilter from gendisk to request_queue

cmd_filter works only for the block layer SG_IO with SCSI block
devices. It breaks scsi/sg.c, bsg, and the block layer SG_IO with SCSI
character devices (such as st). We hit a kernel crash with them.

The problem is that cmd_filter code accesses to gendisk (having struct
blk_scsi_cmd_filter) via inode->i_bdev->bd_disk. It works for only
SCSI block device files. With character device files, inode->i_bdev
leads you to struct cdev. inode->i_bdev->bd_disk->blk_scsi_cmd_filter
isn't safe.

SCSI ULDs don't expose gendisk; they keep it private. bsg needs to be
independent on any protocols. We shouldn't change ULDs to expose their
gendisk.

This patch moves struct blk_scsi_cmd_filter from gendisk to
request_queue, a common object, which eveyone can access to.

The user interface doesn't change; users can change the filters via
/sys/block/. gendisk has a pointer to request_queue so the cmd_filter
code accesses to struct blk_scsi_cmd_filter.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

4 files changed, 110 insertions, 148 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 4889eb86a39e..2cba5ef97b2b 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -582,6 +582,8 @@ blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
 
         q->sg_reserved_size = INT_MAX;
 
+        blk_set_cmd_filter_defaults(&q->cmd_filter);
+
         /*
          * all done
          */
diff --git a/block/bsg.c b/block/bsg.c
index 5a68b09a69ba..0aae8d7ba99c 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -45,8 +45,6 @@ struct bsg_device {
         char name[BUS_ID_SIZE];
         int max_queue;
         unsigned long flags;
-        struct blk_scsi_cmd_filter *cmd_filter;
-        mode_t *f_mode;
 };
 
 enum {
@@ -174,7 +172,8 @@ unlock:
 }
 
 static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
-                                struct sg_io_v4 *hdr, struct bsg_device *bd)
+                                struct sg_io_v4 *hdr, struct bsg_device *bd,
+                                int has_write_perm)
 {
         if (hdr->request_len > BLK_MAX_CDB) {
                 rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL);
@@ -187,8 +186,7 @@ static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
                 return -EFAULT;
 
         if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) {
-                if (blk_cmd_filter_verify_command(bd->cmd_filter, rq->cmd,
-                                                 bd->f_mode))
+                if (blk_verify_command(&q->cmd_filter, rq->cmd, has_write_perm))
                         return -EPERM;
         } else if (!capable(CAP_SYS_RAWIO))
                 return -EPERM;
@@ -244,7 +242,7 @@ bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw)
  * map sg_io_v4 to a request.
  */
 static struct request *
-bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr)
+bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, int has_write_perm)
 {
         struct request_queue *q = bd->queue;
         struct request *rq, *next_rq = NULL;
@@ -266,7 +264,7 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr)
         rq = blk_get_request(q, rw, GFP_KERNEL);
         if (!rq)
                 return ERR_PTR(-ENOMEM);
-        ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd);
+        ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm);
         if (ret)
                 goto out;
 
@@ -568,25 +566,6 @@ static inline void bsg_set_block(struct bsg_device *bd, struct file *file)
                 set_bit(BSG_F_BLOCK, &bd->flags);
 }
 
-static void bsg_set_cmd_filter(struct bsg_device *bd,
-                           struct file *file)
-{
-        struct inode *inode;
-        struct gendisk *disk;
-
-        if (!file)
-                return;
-
-        inode = file->f_dentry->d_inode;
-        if (!inode)
-                return;
-
-        disk = inode->i_bdev->bd_disk;
-
-        bd->cmd_filter = &disk->cmd_filter;
-        bd->f_mode = &file->f_mode;
-}
-
 /*
  * Check if the error is a "real" error that we should return.
  */
@@ -608,7 +587,6 @@ bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
         dprintk("%s: read %Zd bytes\n", bd->name, count);
 
         bsg_set_block(bd, file);
-        bsg_set_cmd_filter(bd, file);
 
         bytes_read = 0;
         ret = __bsg_read(buf, count, bd, NULL, &bytes_read);
@@ -621,7 +599,7 @@ bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 }
 
 static int __bsg_write(struct bsg_device *bd, const char __user *buf,
-                       size_t count, ssize_t *bytes_written)
+                       size_t count, ssize_t *bytes_written, int has_write_perm)
 {
         struct bsg_command *bc;
         struct request *rq;
@@ -652,7 +630,7 @@ static int __bsg_write(struct bsg_device *bd, const char __user *buf,
                 /*
                  * get a request, fill in the blanks, and add to request queue
                  */
-                rq = bsg_map_hdr(bd, &bc->hdr);
+                rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm);
                 if (IS_ERR(rq)) {
                         ret = PTR_ERR(rq);
                         rq = NULL;
@@ -683,10 +661,11 @@ bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
         dprintk("%s: write %Zd bytes\n", bd->name, count);
 
         bsg_set_block(bd, file);
-        bsg_set_cmd_filter(bd, file);
 
         bytes_written = 0;
-        ret = __bsg_write(bd, buf, count, &bytes_written);
+        ret = __bsg_write(bd, buf, count, &bytes_written,
+                          file->f_mode & FMODE_WRITE);
+
         *ppos = bytes_written;
 
         /*
@@ -792,7 +771,6 @@ static struct bsg_device *bsg_add_device(struct inode *inode,
         bd->queue = rq;
 
         bsg_set_block(bd, file);
-        bsg_set_cmd_filter(bd, file);
 
         atomic_set(&bd->ref_count, 1);
         mutex_lock(&bsg_mutex);
@@ -943,7 +921,7 @@ static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
                 if (copy_from_user(&hdr, uarg, sizeof(hdr)))
                         return -EFAULT;
 
-                rq = bsg_map_hdr(bd, &hdr);
+                rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE);
                 if (IS_ERR(rq))
                         return PTR_ERR(rq);
 
diff --git a/block/cmd-filter.c b/block/cmd-filter.c
index eec4404fd357..c705c33361a0 100644
--- a/block/cmd-filter.c
+++ b/block/cmd-filter.c
@@ -27,8 +27,8 @@
 #include <scsi/scsi.h>
 #include <linux/cdrom.h>
 
-int blk_cmd_filter_verify_command(struct blk_scsi_cmd_filter *filter,
-                                  unsigned char *cmd, mode_t *f_mode)
+int blk_verify_command(struct blk_scsi_cmd_filter *filter,
+                       unsigned char *cmd, int has_write_perm)
 {
         /* root can do any command. */
         if (capable(CAP_SYS_RAWIO))
@@ -43,30 +43,11 @@ int blk_cmd_filter_verify_command(struct blk_scsi_cmd_filter *filter,
                 return 0;
 
         /* Write-safe commands require a writable open */
-        if (test_bit(cmd[0], filter->write_ok) && (*f_mode & FMODE_WRITE))
+        if (test_bit(cmd[0], filter->write_ok) && has_write_perm)
                 return 0;
 
         return -EPERM;
 }
-EXPORT_SYMBOL(blk_cmd_filter_verify_command);
-
-int blk_verify_command(struct file *file, unsigned char *cmd)
-{
-        struct gendisk *disk;
-        struct inode *inode;
-
-        if (!file)
-                return -EINVAL;
-
-        inode = file->f_dentry->d_inode;
-        if (!inode)
-                return -EINVAL;
-
-        disk = inode->i_bdev->bd_disk;
-
-        return blk_cmd_filter_verify_command(&disk->cmd_filter,
-                                                 cmd, &file->f_mode);
-}
 EXPORT_SYMBOL(blk_verify_command);
 
 /* and now, the sysfs stuff */
@@ -219,114 +200,27 @@ static struct kobj_type rcf_ktype = {
         .default_attrs = default_attrs,
 };
 
-#ifndef MAINTENANCE_IN_CMD
-#define MAINTENANCE_IN_CMD 0xa3
-#endif
-
-static void rcf_set_defaults(struct blk_scsi_cmd_filter *filter)
-{
-        /* Basic read-only commands */
-        __set_bit(TEST_UNIT_READY, filter->read_ok);
-        __set_bit(REQUEST_SENSE, filter->read_ok);
-        __set_bit(READ_6, filter->read_ok);
-        __set_bit(READ_10, filter->read_ok);
-        __set_bit(READ_12, filter->read_ok);
-        __set_bit(READ_16, filter->read_ok);
-        __set_bit(READ_BUFFER, filter->read_ok);
-        __set_bit(READ_DEFECT_DATA, filter->read_ok);
-        __set_bit(READ_CAPACITY, filter->read_ok);
-        __set_bit(READ_LONG, filter->read_ok);
-        __set_bit(INQUIRY, filter->read_ok);
-        __set_bit(MODE_SENSE, filter->read_ok);
-        __set_bit(MODE_SENSE_10, filter->read_ok);
-        __set_bit(LOG_SENSE, filter->read_ok);
-        __set_bit(START_STOP, filter->read_ok);
-        __set_bit(GPCMD_VERIFY_10, filter->read_ok);
-        __set_bit(VERIFY_16, filter->read_ok);
-        __set_bit(REPORT_LUNS, filter->read_ok);
-        __set_bit(SERVICE_ACTION_IN, filter->read_ok);
-        __set_bit(RECEIVE_DIAGNOSTIC, filter->read_ok);
-        __set_bit(MAINTENANCE_IN_CMD, filter->read_ok);
-        __set_bit(GPCMD_READ_BUFFER_CAPACITY, filter->read_ok);
-
-        /* Audio CD commands */
-        __set_bit(GPCMD_PLAY_CD, filter->read_ok);
-        __set_bit(GPCMD_PLAY_AUDIO_10, filter->read_ok);
-        __set_bit(GPCMD_PLAY_AUDIO_MSF, filter->read_ok);
-        __set_bit(GPCMD_PLAY_AUDIO_TI, filter->read_ok);
-        __set_bit(GPCMD_PAUSE_RESUME, filter->read_ok);
-
-        /* CD/DVD data reading */
-        __set_bit(GPCMD_READ_CD, filter->read_ok);
-        __set_bit(GPCMD_READ_CD_MSF, filter->read_ok);
-        __set_bit(GPCMD_READ_DISC_INFO, filter->read_ok);
-        __set_bit(GPCMD_READ_CDVD_CAPACITY, filter->read_ok);
-        __set_bit(GPCMD_READ_DVD_STRUCTURE, filter->read_ok);
-        __set_bit(GPCMD_READ_HEADER, filter->read_ok);
-        __set_bit(GPCMD_READ_TRACK_RZONE_INFO, filter->read_ok);
-        __set_bit(GPCMD_READ_SUBCHANNEL, filter->read_ok);
-        __set_bit(GPCMD_READ_TOC_PMA_ATIP, filter->read_ok);
-        __set_bit(GPCMD_REPORT_KEY, filter->read_ok);
-        __set_bit(GPCMD_SCAN, filter->read_ok);
-        __set_bit(GPCMD_GET_CONFIGURATION, filter->read_ok);
-        __set_bit(GPCMD_READ_FORMAT_CAPACITIES, filter->read_ok);
-        __set_bit(GPCMD_GET_EVENT_STATUS_NOTIFICATION, filter->read_ok);
-        __set_bit(GPCMD_GET_PERFORMANCE, filter->read_ok);
-        __set_bit(GPCMD_SEEK, filter->read_ok);
-        __set_bit(GPCMD_STOP_PLAY_SCAN, filter->read_ok);
-
-        /* Basic writing commands */
-        __set_bit(WRITE_6, filter->write_ok);
-        __set_bit(WRITE_10, filter->write_ok);
-        __set_bit(WRITE_VERIFY, filter->write_ok);
-        __set_bit(WRITE_12, filter->write_ok);
-        __set_bit(WRITE_VERIFY_12, filter->write_ok);
-        __set_bit(WRITE_16, filter->write_ok);
-        __set_bit(WRITE_LONG, filter->write_ok);
-        __set_bit(WRITE_LONG_2, filter->write_ok);
-        __set_bit(ERASE, filter->write_ok);
-        __set_bit(GPCMD_MODE_SELECT_10, filter->write_ok);
-        __set_bit(MODE_SELECT, filter->write_ok);
-        __set_bit(LOG_SELECT, filter->write_ok);
-        __set_bit(GPCMD_BLANK, filter->write_ok);
-        __set_bit(GPCMD_CLOSE_TRACK, filter->write_ok);
-        __set_bit(GPCMD_FLUSH_CACHE, filter->write_ok);
-        __set_bit(GPCMD_FORMAT_UNIT, filter->write_ok);
-        __set_bit(GPCMD_REPAIR_RZONE_TRACK, filter->write_ok);
-        __set_bit(GPCMD_RESERVE_RZONE_TRACK, filter->write_ok);
-        __set_bit(GPCMD_SEND_DVD_STRUCTURE, filter->write_ok);
-        __set_bit(GPCMD_SEND_EVENT, filter->write_ok);
-        __set_bit(GPCMD_SEND_KEY, filter->write_ok);
-        __set_bit(GPCMD_SEND_OPC, filter->write_ok);
-        __set_bit(GPCMD_SEND_CUE_SHEET, filter->write_ok);
-        __set_bit(GPCMD_SET_SPEED, filter->write_ok);
-        __set_bit(GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL, filter->write_ok);
-        __set_bit(GPCMD_LOAD_UNLOAD, filter->write_ok);
-        __set_bit(GPCMD_SET_STREAMING, filter->write_ok);
-}
-
 int blk_register_filter(struct gendisk *disk)
 {
         int ret;
-        struct blk_scsi_cmd_filter *filter = &disk->cmd_filter;
+        struct blk_scsi_cmd_filter *filter = &disk->queue->cmd_filter;
         struct kobject *parent = kobject_get(disk->holder_dir->parent);
 
         if (!parent)
                 return -ENODEV;
 
         ret = kobject_init_and_add(&filter->kobj, &rcf_ktype, parent,
-                                 "%s", "cmd_filter");
+                                   "%s", "cmd_filter");
 
         if (ret < 0)
                 return ret;
 
-        rcf_set_defaults(filter);
         return 0;
 }
 
 void blk_unregister_filter(struct gendisk *disk)
 {
-        struct blk_scsi_cmd_filter *filter = &disk->cmd_filter;
+        struct blk_scsi_cmd_filter *filter = &disk->queue->cmd_filter;
 
         kobject_put(&filter->kobj);
         kobject_put(disk->holder_dir->parent);
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 12a5182173f6..d01ef5ee427e 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -105,12 +105,96 @@ static int sg_emulated_host(struct request_queue *q, int __user *p)
         return put_user(1, p);
 }
 
+void blk_set_cmd_filter_defaults(struct blk_scsi_cmd_filter *filter)
+{
+        /* Basic read-only commands */
+        __set_bit(TEST_UNIT_READY, filter->read_ok);
+        __set_bit(REQUEST_SENSE, filter->read_ok);
+        __set_bit(READ_6, filter->read_ok);
+        __set_bit(READ_10, filter->read_ok);
+        __set_bit(READ_12, filter->read_ok);
+        __set_bit(READ_16, filter->read_ok);
+        __set_bit(READ_BUFFER, filter->read_ok);
+        __set_bit(READ_DEFECT_DATA, filter->read_ok);
+        __set_bit(READ_CAPACITY, filter->read_ok);
+        __set_bit(READ_LONG, filter->read_ok);
+        __set_bit(INQUIRY, filter->read_ok);
+        __set_bit(MODE_SENSE, filter->read_ok);
+        __set_bit(MODE_SENSE_10, filter->read_ok);
+        __set_bit(LOG_SENSE, filter->read_ok);
+        __set_bit(START_STOP, filter->read_ok);
+        __set_bit(GPCMD_VERIFY_10, filter->read_ok);
+        __set_bit(VERIFY_16, filter->read_ok);
+        __set_bit(REPORT_LUNS, filter->read_ok);
+        __set_bit(SERVICE_ACTION_IN, filter->read_ok);
+        __set_bit(RECEIVE_DIAGNOSTIC, filter->read_ok);
+        __set_bit(MAINTENANCE_IN, filter->read_ok);
+        __set_bit(GPCMD_READ_BUFFER_CAPACITY, filter->read_ok);
+
+        /* Audio CD commands */
+        __set_bit(GPCMD_PLAY_CD, filter->read_ok);
+        __set_bit(GPCMD_PLAY_AUDIO_10, filter->read_ok);
+        __set_bit(GPCMD_PLAY_AUDIO_MSF, filter->read_ok);
+        __set_bit(GPCMD_PLAY_AUDIO_TI, filter->read_ok);
+        __set_bit(GPCMD_PAUSE_RESUME, filter->read_ok);
+
+        /* CD/DVD data reading */
+        __set_bit(GPCMD_READ_CD, filter->read_ok);
+        __set_bit(GPCMD_READ_CD_MSF, filter->read_ok);
+        __set_bit(GPCMD_READ_DISC_INFO, filter->read_ok);
+        __set_bit(GPCMD_READ_CDVD_CAPACITY, filter->read_ok);
+        __set_bit(GPCMD_READ_DVD_STRUCTURE, filter->read_ok);
+        __set_bit(GPCMD_READ_HEADER, filter->read_ok);
+        __set_bit(GPCMD_READ_TRACK_RZONE_INFO, filter->read_ok);
+        __set_bit(GPCMD_READ_SUBCHANNEL, filter->read_ok);
+        __set_bit(GPCMD_READ_TOC_PMA_ATIP, filter->read_ok);
+        __set_bit(GPCMD_REPORT_KEY, filter->read_ok);
+        __set_bit(GPCMD_SCAN, filter->read_ok);
+        __set_bit(GPCMD_GET_CONFIGURATION, filter->read_ok);
+        __set_bit(GPCMD_READ_FORMAT_CAPACITIES, filter->read_ok);
+        __set_bit(GPCMD_GET_EVENT_STATUS_NOTIFICATION, filter->read_ok);
+        __set_bit(GPCMD_GET_PERFORMANCE, filter->read_ok);
+        __set_bit(GPCMD_SEEK, filter->read_ok);
+        __set_bit(GPCMD_STOP_PLAY_SCAN, filter->read_ok);
+
+        /* Basic writing commands */
+        __set_bit(WRITE_6, filter->write_ok);
+        __set_bit(WRITE_10, filter->write_ok);
+        __set_bit(WRITE_VERIFY, filter->write_ok);
+        __set_bit(WRITE_12, filter->write_ok);
+        __set_bit(WRITE_VERIFY_12, filter->write_ok);
+        __set_bit(WRITE_16, filter->write_ok);
+        __set_bit(WRITE_LONG, filter->write_ok);
+        __set_bit(WRITE_LONG_2, filter->write_ok);
+        __set_bit(ERASE, filter->write_ok);
+        __set_bit(GPCMD_MODE_SELECT_10, filter->write_ok);
+        __set_bit(MODE_SELECT, filter->write_ok);
+        __set_bit(LOG_SELECT, filter->write_ok);
+        __set_bit(GPCMD_BLANK, filter->write_ok);
+        __set_bit(GPCMD_CLOSE_TRACK, filter->write_ok);
+        __set_bit(GPCMD_FLUSH_CACHE, filter->write_ok);
+        __set_bit(GPCMD_FORMAT_UNIT, filter->write_ok);
+        __set_bit(GPCMD_REPAIR_RZONE_TRACK, filter->write_ok);
+        __set_bit(GPCMD_RESERVE_RZONE_TRACK, filter->write_ok);
+        __set_bit(GPCMD_SEND_DVD_STRUCTURE, filter->write_ok);
+        __set_bit(GPCMD_SEND_EVENT, filter->write_ok);
+        __set_bit(GPCMD_SEND_KEY, filter->write_ok);
+        __set_bit(GPCMD_SEND_OPC, filter->write_ok);
+        __set_bit(GPCMD_SEND_CUE_SHEET, filter->write_ok);
+        __set_bit(GPCMD_SET_SPEED, filter->write_ok);
+        __set_bit(GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL, filter->write_ok);
+        __set_bit(GPCMD_LOAD_UNLOAD, filter->write_ok);
+        __set_bit(GPCMD_SET_STREAMING, filter->write_ok);
+}
+EXPORT_SYMBOL_GPL(blk_set_cmd_filter_defaults);
+
 static int blk_fill_sghdr_rq(struct request_queue *q, struct request *rq,
                              struct sg_io_hdr *hdr, struct file *file)
 {
         if (copy_from_user(rq->cmd, hdr->cmdp, hdr->cmd_len))
                 return -EFAULT;
-        if (blk_verify_command(file, rq->cmd))
+        if (blk_verify_command(&q->cmd_filter, rq->cmd,
+                               file->f_mode & FMODE_WRITE))
                 return -EPERM;
 
         /*
@@ -298,7 +382,7 @@ int sg_scsi_ioctl(struct file *file, struct request_queue *q,
                   struct gendisk *disk, struct scsi_ioctl_command __user *sic)
 {
         struct request *rq;
-        int err;
+        int err, write_perm = 0;
         unsigned int in_len, out_len, bytes, opcode, cmdlen;
         char *buffer = NULL, sense[SCSI_SENSE_BUFFERSIZE];
 
@@ -340,7 +424,11 @@ int sg_scsi_ioctl(struct file *file, struct request_queue *q,
         if (in_len && copy_from_user(buffer, sic->data + cmdlen, in_len))
                 goto error;
 
-        err = blk_verify_command(file, rq->cmd);
+        /* scsi_ioctl passes NULL */
+        if (file && (file->f_mode & FMODE_WRITE))
+                write_perm = 1;
+
+        err = blk_verify_command(&q->cmd_filter, rq->cmd, write_perm);
         if (err)
                 goto error;