linux-kernel - [PATCH 03/10] scsi: NCR5380: Replace snprintf() with the safer scnprintf() variant

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Message-ID: <20240208084512.3803250-4-lee@kernel.org>
Date: Thu,  8 Feb 2024 08:44:15 +0000
From: Lee Jones <lee@...nel.org>
To: lee@...nel.org
Cc: linux-kernel@...r.kernel.org,
	linux-hardening@...r.kernel.org,
	Finn Thain <fthain@...ux-m68k.org>,
	Michael Schmitz <schmitzmic@...il.com>,
	"James E.J. Bottomley" <jejb@...ux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@...cle.com>,
	drew@...orado.edu,
	Tnx to <Thomas_Roesch@...maus.de>,
	linux-scsi@...r.kernel.org
Subject: [PATCH 03/10] scsi: NCR5380: Replace snprintf() with the safer scnprintf() variant

There is a general misunderstanding amongst engineers that {v}snprintf()
returns the length of the data *actually* encoded into the destination
array.  However, as per the C99 standard {v}snprintf() really returns
the length of the data that *would have been* written if there were
enough space for it.  This misunderstanding has led to buffer-overruns
in the past.  It's generally considered safer to use the {v}scnprintf()
variants in their place (or even sprintf() in simple cases).  So let's
do that.

Link: https://lwn.net/Articles/69419/
Link: https://github.com/KSPP/linux/issues/105
Signed-off-by: Lee Jones <lee@...nel.org>
---
Cc: Finn Thain <fthain@...ux-m68k.org>
Cc: Michael Schmitz <schmitzmic@...il.com>
Cc: "James E.J. Bottomley" <jejb@...ux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@...cle.com>
Cc: drew@...orado.edu
Cc: Tnx to <Thomas_Roesch@...maus.de>
Cc: linux-scsi@...r.kernel.org
---
 drivers/scsi/NCR5380.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c
index cea3a79d538e4..ea565e843c765 100644
--- a/drivers/scsi/NCR5380.c
+++ b/drivers/scsi/NCR5380.c
@@ -421,14 +421,14 @@ static int NCR5380_init(struct Scsi_Host *instance, int flags)
 	if (!hostdata->work_q)
 		return -ENOMEM;
 
-	snprintf(hostdata->info, sizeof(hostdata->info),
-		"%s, irq %d, io_port 0x%lx, base 0x%lx, can_queue %d, cmd_per_lun %d, sg_tablesize %d, this_id %d, flags { %s%s%s}",
-		instance->hostt->name, instance->irq, hostdata->io_port,
-		hostdata->base, instance->can_queue, instance->cmd_per_lun,
-		instance->sg_tablesize, instance->this_id,
-		hostdata->flags & FLAG_DMA_FIXUP     ? "DMA_FIXUP "     : "",
-		hostdata->flags & FLAG_NO_PSEUDO_DMA ? "NO_PSEUDO_DMA " : "",
-		hostdata->flags & FLAG_TOSHIBA_DELAY ? "TOSHIBA_DELAY " : "");
+	scnprintf(hostdata->info, sizeof(hostdata->info),
+		 "%s, irq %d, io_port 0x%lx, base 0x%lx, can_queue %d, cmd_per_lun %d, sg_tablesize %d, this_id %d, flags { %s%s%s}",
+		 instance->hostt->name, instance->irq, hostdata->io_port,
+		 hostdata->base, instance->can_queue, instance->cmd_per_lun,
+		 instance->sg_tablesize, instance->this_id,
+		 hostdata->flags & FLAG_DMA_FIXUP     ? "DMA_FIXUP "     : "",
+		 hostdata->flags & FLAG_NO_PSEUDO_DMA ? "NO_PSEUDO_DMA " : "",
+		 hostdata->flags & FLAG_TOSHIBA_DELAY ? "TOSHIBA_DELAY " : "");
 
 	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 	NCR5380_write(MODE_REG, MR_BASE);
-- 
2.43.0.594.gd9cf4e227d-goog