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authorDamien Le Moal2021-08-20 16:02:54 +0900
committerMartin K. Petersen2021-09-29 00:10:57 -0400
commita7d6840bed0c2b16ac3071b74b5fcf08fc488241 (patch)
tree7788b3578e71ad8122198d8587b515149485fbc1
parent17b49bcbf8351d3dbe57204468ac34f033ed60bc (diff)
scsi: core: Fix scsi_mode_select() buffer length handling
The MODE SELECT(6) command allows handling mode page buffers that are up to 255 bytes, including the 4 byte header needed in front of the page buffer. For requests larger than this limit, automatically use the MODE SELECT(10) command. In both cases, since scsi_mode_select() adds the mode select page header, checks on the buffer length value must include this header size to avoid overflows of the command CDB allocation length field. While at it, use put_unaligned_be16() for setting the header block descriptor length and CDB allocation length when using MODE SELECT(10). [mkp: fix MODE SENSE vs. MODE SELECT confusion] Link: https://lore.kernel.org/r/20210820070255.682775-3-damien.lemoal@wdc.com Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
-rw-r--r--drivers/scsi/scsi_lib.c21
1 files changed, 13 insertions, 8 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 701d8e8480f2..dcf105287a76 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2026,8 +2026,15 @@ scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
memset(cmd, 0, sizeof(cmd));
cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
- if (sdev->use_10_for_ms) {
- if (len > 65535)
+ /*
+ * Use MODE SELECT(10) if the device asked for it or if the mode page
+ * and the mode select header cannot fit within the maximumm 255 bytes
+ * of the MODE SELECT(6) command.
+ */
+ if (sdev->use_10_for_ms ||
+ len + 4 > 255 ||
+ data->block_descriptor_length > 255) {
+ if (len > 65535 - 8)
return -EINVAL;
real_buffer = kmalloc(8 + len, GFP_KERNEL);
if (!real_buffer)
@@ -2040,15 +2047,13 @@ scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
real_buffer[3] = data->device_specific;
real_buffer[4] = data->longlba ? 0x01 : 0;
real_buffer[5] = 0;
- real_buffer[6] = data->block_descriptor_length >> 8;
- real_buffer[7] = data->block_descriptor_length;
+ put_unaligned_be16(data->block_descriptor_length,
+ &real_buffer[6]);
cmd[0] = MODE_SELECT_10;
- cmd[7] = len >> 8;
- cmd[8] = len;
+ put_unaligned_be16(len, &cmd[7]);
} else {
- if (len > 255 || data->block_descriptor_length > 255 ||
- data->longlba)
+ if (data->longlba)
return -EINVAL;
real_buffer = kmalloc(4 + len, GFP_KERNEL);