[PATCH 06/10] scsi: aha1542: Replace snprintf() with the safer scnprintf() variant

Lee Jones
2024-02-08T08:45:32Z

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@kernel.org>
---
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org
---
drivers/scsi/aha1542.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/aha1542.c b/drivers/scsi/aha1542.c
index 9503996c63256..b5ec7887801a5 100644
--- a/drivers/scsi/aha1542.c
+++ b/drivers/scsi/aha1542.c
@@ -772,7 +772,7 @@ static struct Scsi_Host *aha1542_hw_init(const struct scsi_host_template *tpnt,
goto unregister;

if (sh->dma_channel != 0xFF)
- snprintf(dma_info, sizeof(dma_info), "DMA %d", sh->dma_channel);
+ scnprintf(dma_info, sizeof(dma_info), "DMA %d", sh->dma_channel);
shost_printk(KERN_INFO, sh, "Adaptec AHA-1542 (SCSI-ID %d) at IO 0x%x, IRQ %d, %s\n",
sh->this_id, base_io, sh->irq, dma_info);
if (aha1542->bios_translation == BIOS_TRANSLATION_25563)
--
2.43.0.594.gd9cf4e227d-goog