scsi: Protect against buffer possible overflow in scsi_set_sense_information

Make sure that the input sense buffer has sufficient length
to fit the information descriptor (12 additional bytes).
Modify scsi_set_sense_information to receive the sense buffer
length and adjust its callers scsi target and libata.

(Fix patch fuzz in scsi_set_sense_information - nab)

Reported-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

4 files changed, 27 insertions, 6 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 3131adcc1f87..2fb7c79e727f 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -289,7 +289,9 @@ void ata_scsi_set_sense_information(struct scsi_cmnd *cmd,
                 return;
 
         information = ata_tf_read_block(tf, NULL);
-        scsi_set_sense_information(cmd->sense_buffer, information);
+        scsi_set_sense_information(cmd->sense_buffer,
+                                   SCSI_SENSE_BUFFERSIZE,
+                                   information);
 }
 
 static ssize_t
diff --git a/drivers/scsi/scsi_common.c b/drivers/scsi/scsi_common.c
index ee6bdf43a8ea..c126966130ab 100644
--- a/drivers/scsi/scsi_common.c
+++ b/drivers/scsi/scsi_common.c
@@ -5,6 +5,7 @@
 #include <linux/bug.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
+#include <linux/errno.h>
 #include <asm/unaligned.h>
 #include <scsi/scsi_common.h>
 
@@ -249,10 +250,13 @@ EXPORT_SYMBOL(scsi_build_sense_buffer);
  * scsi_set_sense_information - set the information field in a
  *              formatted sense data buffer
  * @buf:        Where to build sense data
+ * @buf_len:    buffer length
  * @info:       64-bit information value to be set
  *
+ * Return value:
+ *      0 on success or EINVAL for invalid sense buffer length
  **/
-void scsi_set_sense_information(u8 *buf, u64 info)
+int scsi_set_sense_information(u8 *buf, int buf_len, u64 info)
 {
         if ((buf[0] & 0x7f) == 0x72) {
                 u8 *ucp, len;
@@ -263,6 +267,11 @@ void scsi_set_sense_information(u8 *buf, u64 info)
                         buf[7] = len + 0xc;
                         ucp = buf + 8 + len;
                 }
+
+                if (buf_len < len + 0xc)
+                        /* Not enough room for info */
+                        return -EINVAL;
+
                 ucp[0] = 0;
                 ucp[1] = 0xa;
                 ucp[2] = 0x80; /* Valid bit */
@@ -272,5 +281,7 @@ void scsi_set_sense_information(u8 *buf, u64 info)
                 buf[0] |= 0x80;
                 put_unaligned_be64(info, &buf[3]);
         }
+
+        return 0;
 }
 EXPORT_SYMBOL(scsi_set_sense_information);
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 2bece607ca0f..7fb031bbcc8d 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2729,7 +2729,7 @@ static const struct sense_info sense_info_table[] = {
         },
 };
 
-static void translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
+static int translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
 {
         const struct sense_info *si;
         u8 *buffer = cmd->sense_buffer;
@@ -2756,7 +2756,11 @@ static void translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
 
         scsi_build_sense_buffer(0, buffer, si->key, asc, ascq);
         if (si->add_sector_info)
-                scsi_set_sense_information(buffer, cmd->bad_sector);
+                return scsi_set_sense_information(buffer,
+                                                  cmd->scsi_sense_length,
+                                                  cmd->bad_sector);
+
+        return 0;
 }
 
 int
@@ -2774,10 +2778,14 @@ transport_send_check_condition_and_sense(struct se_cmd *cmd,
         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 
         if (!from_transport) {
+                int rc;
+
                 cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
-                translate_sense_reason(cmd, reason);
                 cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
                 cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
+                rc = translate_sense_reason(cmd, reason);
+                if (rc)
+                        return rc;
         }
 
         trace_target_cmd_complete(cmd);
diff --git a/include/scsi/scsi_common.h b/include/scsi/scsi_common.h
index 156d673db900..11571b2a831e 100644
--- a/include/scsi/scsi_common.h
+++ b/include/scsi/scsi_common.h
@@ -62,7 +62,7 @@ extern bool scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
                                  struct scsi_sense_hdr *sshdr);
 
 extern void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq);
-extern void scsi_set_sense_information(u8 *buf, u64 info);
+int scsi_set_sense_information(u8 *buf, int buf_len, u64 info);
 extern const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
                                        int desc_type);