target: report too-small parameter lists everywhere

Several places were not checking that the parameter list length
was large enough, and thus accessing invalid memory.  Zero-length
parameter lists are just a special case of this.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 15 insertions, 2 deletions

diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 76db75e836ed..9ba495477fd2 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -325,17 +325,30 @@ static int iblock_execute_unmap(struct se_cmd *cmd)
         struct iblock_dev *ibd = dev->dev_ptr;
         unsigned char *buf, *ptr = NULL;
         sector_t lba;
-        int size = cmd->data_length;
+        int size;
         u32 range;
         int ret = 0;
         int dl, bd_dl;
 
+        if (cmd->data_length < 8) {
+                pr_warn("UNMAP parameter list length %u too small\n",
+                        cmd->data_length);
+                cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
+                return -EINVAL;
+        }
+
         buf = transport_kmap_data_sg(cmd);
 
         dl = get_unaligned_be16(&buf[0]);
         bd_dl = get_unaligned_be16(&buf[2]);
 
-        size = min(size - 8, bd_dl);
+        size = cmd->data_length - 8;
+        if (bd_dl > size)
+                pr_warn("UNMAP parameter list length %u too small, ignoring bd_dl %u\n",
+                        cmd->data_length, bd_dl);
+        else
+                size = bd_dl;
+
         if (size / 16 > dev->se_sub_dev->se_dev_attrib.max_unmap_block_desc_count) {
                 cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
                 ret = -EINVAL;