[PATCH] scsi: 3w-sas: Replace 1-element arrays with flexible array members

Kees Cook
2023-01-05T00:52:58Z

One-element arrays (and multi-element arrays being treated as
dynamically sized) are deprecated[1] and are being replaced with
flexible array members in support of the ongoing efforts to tighten the
FORTIFY_SOURCE routines on memcpy(), correctly instrument array indexing
with UBSAN_BOUNDS, and to globally enable -fstrict-flex-arrays=3.

Replace one-element arrays with flexible-array member in TW_Ioctl_Buf_Apache
and TW_Param_Apache, adjusting the explicit sizing calculations at the
same time.

This results in no differences in binary output.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays

Cc: Adam Radford <aradford@gmail.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/scsi/3w-sas.c | 12 ++++++------
drivers/scsi/3w-sas.h | 4 ++--
2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/3w-sas.c b/drivers/scsi/3w-sas.c
index 3ebe66151dcb..f41c93454f0c 100644
--- a/drivers/scsi/3w-sas.c
+++ b/drivers/scsi/3w-sas.c
@@ -690,7 +690,7 @@ static void twl_load_sgl(TW_Device_Extension *tw_dev, TW_Command_Full *full_comm
newcommand->request_id__lunl =
cpu_to_le16(TW_REQ_LUN_IN(TW_LUN_OUT(newcommand->request_id__lunl), request_id));
if (length) {
- newcommand->sg_list[0].address = TW_CPU_TO_SGL(dma_handle + sizeof(TW_Ioctl_Buf_Apache) - 1);
+ newcommand->sg_list[0].address = TW_CPU_TO_SGL(dma_handle + sizeof(TW_Ioctl_Buf_Apache));
newcommand->sg_list[0].length = TW_CPU_TO_SGL(length);
}
newcommand->sgl_entries__lunh =
@@ -702,7 +702,7 @@ static void twl_load_sgl(TW_Device_Extension *tw_dev, TW_Command_Full *full_comm
if (TW_SGL_OUT(oldcommand->opcode__sgloffset)) {
/* Load the sg list */
sgl = (TW_SG_Entry_ISO *)((u32 *)oldcommand+oldcommand->size - (sizeof(TW_SG_Entry_ISO)/4) + pae + (sizeof(dma_addr_t) > 4 ? 1 : 0));
- sgl->address = TW_CPU_TO_SGL(dma_handle + sizeof(TW_Ioctl_Buf_Apache) - 1);
+ sgl->address = TW_CPU_TO_SGL(dma_handle + sizeof(TW_Ioctl_Buf_Apache));
sgl->length = TW_CPU_TO_SGL(length);
oldcommand->size += pae;
oldcommand->size += sizeof(dma_addr_t) > 4 ? 1 : 0;
@@ -748,7 +748,7 @@ static long twl_chrdev_ioctl(struct file *file, unsigned int cmd, unsigned long
data_buffer_length_adjusted = (driver_command.buffer_length + 511) & ~511;

/* Now allocate ioctl buf memory */
- cpu_addr = dma_alloc_coherent(&tw_dev->tw_pci_dev->dev, data_buffer_length_adjusted+sizeof(TW_Ioctl_Buf_Apache) - 1, &dma_handle, GFP_KERNEL);
+ cpu_addr = dma_alloc_coherent(&tw_dev->tw_pci_dev->dev, data_buffer_length_adjusted + sizeof(TW_Ioctl_Buf_Apache), &dma_handle, GFP_KERNEL);
if (!cpu_addr) {
retval = -ENOMEM;
goto out2;
@@ -757,7 +757,7 @@ static long twl_chrdev_ioctl(struct file *file, unsigned int cmd, unsigned long
tw_ioctl = (TW_Ioctl_Buf_Apache *)cpu_addr;

/* Now copy down the entire ioctl */
- if (copy_from_user(tw_ioctl, argp, driver_command.buffer_length + sizeof(TW_Ioctl_Buf_Apache) - 1))
+ if (copy_from_user(tw_ioctl, argp, driver_command.buffer_length + sizeof(TW_Ioctl_Buf_Apache)))
goto out3;

/* See which ioctl we are doing */
@@ -815,11 +815,11 @@ static long twl_chrdev_ioctl(struct file *file, unsigned int cmd, unsigned long
}

/* Now copy the entire response to userspace */
- if (copy_to_user(argp, tw_ioctl, sizeof(TW_Ioctl_Buf_Apache) + driver_command.buffer_length - 1) == 0)
+ if (copy_to_user(argp, tw_ioctl, sizeof(TW_Ioctl_Buf_Apache) + driver_command.buffer_length) == 0)
retval = 0;
out3:
/* Now free ioctl buf memory */
- dma_free_coherent(&tw_dev->tw_pci_dev->dev, data_buffer_length_adjusted+sizeof(TW_Ioctl_Buf_Apache) - 1, cpu_addr, dma_handle);
+ dma_free_coherent(&tw_dev->tw_pci_dev->dev, data_buffer_length_adjusted + sizeof(TW_Ioctl_Buf_Apache), cpu_addr, dma_handle);
out2:
mutex_unlock(&tw_dev->ioctl_lock);
out:
diff --git a/drivers/scsi/3w-sas.h b/drivers/scsi/3w-sas.h
index b0508039a280..096dec29e2ac 100644
--- a/drivers/scsi/3w-sas.h
+++ b/drivers/scsi/3w-sas.h
@@ -335,7 +335,7 @@ typedef struct TAG_TW_Ioctl_Apache {
TW_Ioctl_Driver_Command driver_command;
char padding[488];
TW_Command_Full firmware_command;
- char data_buffer[1];
+ char data_buffer[];
} TW_Ioctl_Buf_Apache;

/* GetParam descriptor */
@@ -344,7 +344,7 @@ typedef struct {
unsigned short parameter_id;
unsigned short parameter_size_bytes;
unsigned short actual_parameter_size_bytes;
- unsigned char data[1];
+ unsigned char data[];
} TW_Param_Apache;

/* Compatibility information structure */
--
2.34.1