[PATCH 2/2] scsi: aacraid: struct {user,}sgmap{,64,raw}: Replace 1-element arrays with flexible arrays

From: Kees Cook
Date: Thu Jul 11 2024 - 17:58:02 EST


Replace the deprecated[1] use of 1-element arrays in
struct sgmap, struct sgmap64, struct sgmapraw, struct user_sgmap,
and struct user_sgmap64 with modern flexible arrays. Additionally
remove struct user_sgmapraw as it is unused.

The resulting binary output differences from this change are limited
only to stack space consumption of the smaller "srbu" variable
in aac_issue_safw_bmic_identify() and aac_get_safw_ciss_luns(),
as well as the smaller associated pair of memcpy()s in
aac_send_safw_bmic_cmd(). Artificially growing the size of srbu back to
its prior size removes all binary differences[2].

As an aside, after studying the aacraid driver code I wonder how
aac_send_wellness_command() ever works. It is reporting a size 4 bytes
too small for what it has constructed in memory in the DMA region:
sgentry64 is size 12, whereas sgentry is size 8. Perhaps the hardware
doesn't care. (Regardless, it is unchanged by this patch.)

Link: https://github.com/KSPP/linux/issues/79 [1]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/commit/?h=dev/v6.10-rc2/1-element&id=45e6226bcbc5e982541754eca7ac29f403e82f5e [2]
Signed-off-by: Kees Cook <kees@xxxxxxxxxx>
---
Cc: Adaptec OEM Raid Solutions <aacraid@xxxxxxxxxxxxx>
Cc: "James E.J. Bottomley" <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
Cc: linux-scsi@xxxxxxxxxxxxxxx
---
drivers/scsi/aacraid/aachba.c | 26 ++++++++++++--------------
drivers/scsi/aacraid/aacraid.h | 15 +++++----------
drivers/scsi/aacraid/commctrl.c | 4 ++--
drivers/scsi/aacraid/comminit.c | 3 +--
drivers/scsi/aacraid/commsup.c | 5 +++--
5 files changed, 23 insertions(+), 30 deletions(-)

diff --git a/drivers/scsi/aacraid/aachba.c b/drivers/scsi/aacraid/aachba.c
index 497c6dd5df91..ec3834bda111 100644
--- a/drivers/scsi/aacraid/aachba.c
+++ b/drivers/scsi/aacraid/aachba.c
@@ -1267,7 +1267,7 @@ static int aac_read_raw_io(struct fib * fib, struct scsi_cmnd * cmd, u64 lba, u3
return ret;
command = ContainerRawIo;
fibsize = sizeof(struct aac_raw_io) +
- ((le32_to_cpu(readcmd->sg.count)-1) * sizeof(struct sgentryraw));
+ (le32_to_cpu(readcmd->sg.count) * sizeof(struct sgentryraw));
}

BUG_ON(fibsize > (fib->dev->max_fib_size - sizeof(struct aac_fibhdr)));
@@ -1302,7 +1302,7 @@ static int aac_read_block64(struct fib * fib, struct scsi_cmnd * cmd, u64 lba, u
if (ret < 0)
return ret;
fibsize = sizeof(struct aac_read64) +
- ((le32_to_cpu(readcmd->sg.count) - 1) *
+ (le32_to_cpu(readcmd->sg.count) *
sizeof (struct sgentry64));
BUG_ON (fibsize > (fib->dev->max_fib_size -
sizeof(struct aac_fibhdr)));
@@ -1337,7 +1337,7 @@ static int aac_read_block(struct fib * fib, struct scsi_cmnd * cmd, u64 lba, u32
if (ret < 0)
return ret;
fibsize = sizeof(struct aac_read) +
- ((le32_to_cpu(readcmd->sg.count) - 1) *
+ (le32_to_cpu(readcmd->sg.count) *
sizeof (struct sgentry));
BUG_ON (fibsize > (fib->dev->max_fib_size -
sizeof(struct aac_fibhdr)));
@@ -1401,7 +1401,7 @@ static int aac_write_raw_io(struct fib * fib, struct scsi_cmnd * cmd, u64 lba, u
return ret;
command = ContainerRawIo;
fibsize = sizeof(struct aac_raw_io) +
- ((le32_to_cpu(writecmd->sg.count)-1) * sizeof (struct sgentryraw));
+ (le32_to_cpu(writecmd->sg.count) * sizeof(struct sgentryraw));
}

BUG_ON(fibsize > (fib->dev->max_fib_size - sizeof(struct aac_fibhdr)));
@@ -1436,7 +1436,7 @@ static int aac_write_block64(struct fib * fib, struct scsi_cmnd * cmd, u64 lba,
if (ret < 0)
return ret;
fibsize = sizeof(struct aac_write64) +
- ((le32_to_cpu(writecmd->sg.count) - 1) *
+ (le32_to_cpu(writecmd->sg.count) *
sizeof (struct sgentry64));
BUG_ON (fibsize > (fib->dev->max_fib_size -
sizeof(struct aac_fibhdr)));
@@ -1473,7 +1473,7 @@ static int aac_write_block(struct fib * fib, struct scsi_cmnd * cmd, u64 lba, u3
if (ret < 0)
return ret;
fibsize = sizeof(struct aac_write) +
- ((le32_to_cpu(writecmd->sg.count) - 1) *
+ (le32_to_cpu(writecmd->sg.count) *
sizeof (struct sgentry));
BUG_ON (fibsize > (fib->dev->max_fib_size -
sizeof(struct aac_fibhdr)));
@@ -1592,9 +1592,9 @@ static int aac_scsi_64(struct fib * fib, struct scsi_cmnd * cmd)
/*
* Build Scatter/Gather list
*/
- fibsize = sizeof (struct aac_srb) - sizeof (struct sgentry) +
+ fibsize = sizeof(struct aac_srb) +
((le32_to_cpu(srbcmd->sg.count) & 0xff) *
- sizeof (struct sgentry64));
+ sizeof(struct sgentry64));
BUG_ON (fibsize > (fib->dev->max_fib_size -
sizeof(struct aac_fibhdr)));

@@ -1624,7 +1624,7 @@ static int aac_scsi_32(struct fib * fib, struct scsi_cmnd * cmd)
* Build Scatter/Gather list
*/
fibsize = sizeof (struct aac_srb) +
- (((le32_to_cpu(srbcmd->sg.count) & 0xff) - 1) *
+ ((le32_to_cpu(srbcmd->sg.count) & 0xff) *
sizeof (struct sgentry));
BUG_ON (fibsize > (fib->dev->max_fib_size -
sizeof(struct aac_fibhdr)));
@@ -1693,8 +1693,7 @@ static int aac_send_safw_bmic_cmd(struct aac_dev *dev,
fibptr->hw_fib_va->header.XferState &=
~cpu_to_le32(FastResponseCapable);

- fibsize = sizeof(struct aac_srb) - sizeof(struct sgentry) +
- sizeof(struct sgentry64);
+ fibsize = sizeof(struct aac_srb) + sizeof(struct sgentry64);

/* allocate DMA buffer for response */
addr = dma_map_single(&dev->pdev->dev, xfer_buf, xfer_len,
@@ -2267,7 +2266,7 @@ int aac_get_adapter_info(struct aac_dev* dev)
dev->a_ops.adapter_bounds = aac_bounds_32;
dev->scsi_host_ptr->sg_tablesize = (dev->max_fib_size -
sizeof(struct aac_fibhdr) -
- sizeof(struct aac_write) + sizeof(struct sgentry)) /
+ sizeof(struct aac_write)) /
sizeof(struct sgentry);
if (dev->dac_support) {
dev->a_ops.adapter_read = aac_read_block64;
@@ -2278,8 +2277,7 @@ int aac_get_adapter_info(struct aac_dev* dev)
dev->scsi_host_ptr->sg_tablesize =
(dev->max_fib_size -
sizeof(struct aac_fibhdr) -
- sizeof(struct aac_write64) +
- sizeof(struct sgentry64)) /
+ sizeof(struct aac_write64)) /
sizeof(struct sgentry64);
} else {
dev->a_ops.adapter_read = aac_read_block;
diff --git a/drivers/scsi/aacraid/aacraid.h b/drivers/scsi/aacraid/aacraid.h
index 8e7a0a5cb7aa..1d09d3ac6aa4 100644
--- a/drivers/scsi/aacraid/aacraid.h
+++ b/drivers/scsi/aacraid/aacraid.h
@@ -507,32 +507,27 @@ struct sge_ieee1212 {

struct sgmap {
__le32 count;
- struct sgentry sg[1];
+ struct sgentry sg[];
};

struct user_sgmap {
u32 count;
- struct user_sgentry sg[1];
+ struct user_sgentry sg[];
};

struct sgmap64 {
__le32 count;
- struct sgentry64 sg[1];
+ struct sgentry64 sg[];
};

struct user_sgmap64 {
u32 count;
- struct user_sgentry64 sg[1];
+ struct user_sgentry64 sg[];
};

struct sgmapraw {
__le32 count;
- struct sgentryraw sg[1];
-};
-
-struct user_sgmapraw {
- u32 count;
- struct user_sgentryraw sg[1];
+ struct sgentryraw sg[];
};

struct creation_info
diff --git a/drivers/scsi/aacraid/commctrl.c b/drivers/scsi/aacraid/commctrl.c
index e7cc927ed952..68240d6f27ab 100644
--- a/drivers/scsi/aacraid/commctrl.c
+++ b/drivers/scsi/aacraid/commctrl.c
@@ -523,7 +523,7 @@ static int aac_send_raw_srb(struct aac_dev* dev, void __user * arg)
goto cleanup;
}

- if ((fibsize < (sizeof(struct user_aac_srb) - sizeof(struct user_sgentry))) ||
+ if ((fibsize < sizeof(struct user_aac_srb)) ||
(fibsize > (dev->max_fib_size - sizeof(struct aac_fibhdr)))) {
rcode = -EINVAL;
goto cleanup;
@@ -561,7 +561,7 @@ static int aac_send_raw_srb(struct aac_dev* dev, void __user * arg)
rcode = -EINVAL;
goto cleanup;
}
- actual_fibsize = sizeof(struct aac_srb) - sizeof(struct sgentry) +
+ actual_fibsize = sizeof(struct aac_srb) +
((user_srbcmd->sg.count & 0xff) * sizeof(struct sgentry));
actual_fibsize64 = actual_fibsize + (user_srbcmd->sg.count & 0xff) *
(sizeof(struct sgentry64) - sizeof(struct sgentry));
diff --git a/drivers/scsi/aacraid/comminit.c b/drivers/scsi/aacraid/comminit.c
index bd99c5492b7d..fee857236991 100644
--- a/drivers/scsi/aacraid/comminit.c
+++ b/drivers/scsi/aacraid/comminit.c
@@ -522,8 +522,7 @@ struct aac_dev *aac_init_adapter(struct aac_dev *dev)
spin_lock_init(&dev->iq_lock);
dev->max_fib_size = sizeof(struct hw_fib);
dev->sg_tablesize = host->sg_tablesize = (dev->max_fib_size
- - sizeof(struct aac_fibhdr)
- - sizeof(struct aac_write) + sizeof(struct sgentry))
+ - sizeof(struct aac_fibhdr) - sizeof(struct aac_write))
/ sizeof(struct sgentry);
dev->comm_interface = AAC_COMM_PRODUCER;
dev->raw_io_interface = dev->raw_io_64 = 0;
diff --git a/drivers/scsi/aacraid/commsup.c b/drivers/scsi/aacraid/commsup.c
index 25cee03d7f97..47287559c768 100644
--- a/drivers/scsi/aacraid/commsup.c
+++ b/drivers/scsi/aacraid/commsup.c
@@ -2327,8 +2327,9 @@ static int aac_send_wellness_command(struct aac_dev *dev, char *wellness_str,
sg64->sg[0].addr[0] = cpu_to_le32((u32)(addr & 0xffffffff));
sg64->sg[0].count = cpu_to_le32(datasize);

- ret = aac_fib_send(ScsiPortCommand64, fibptr, sizeof(struct aac_srb),
- FsaNormal, 1, 1, NULL, NULL);
+ ret = aac_fib_send(ScsiPortCommand64, fibptr,
+ sizeof(struct aac_srb) + sizeof(struct sgentry),
+ FsaNormal, 1, 1, NULL, NULL);

dma_free_coherent(&dev->pdev->dev, datasize, dma_buf, addr);

--
2.34.1