[PATCH 08/10] scsi: aic7xxx: aicasm: Replace snprintf() with the safer scnprintf() variant

Lee Jones
2024-02-08T08:45:35Z

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: Hannes Reinecke <hare@suse.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Lee Jones <lee@kernel.org>
Cc: linux-scsi@vger.kernel.org
---
drivers/scsi/aic7xxx/aicasm/aicasm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/aic7xxx/aicasm/aicasm.c b/drivers/scsi/aic7xxx/aicasm/aicasm.c
index 8d995186e557a..bc758e78d3c06 100644
--- a/drivers/scsi/aic7xxx/aicasm/aicasm.c
+++ b/drivers/scsi/aic7xxx/aicasm/aicasm.c
@@ -331,7 +331,7 @@ back_patch()
if (cur_instr->patch_label->type != LABEL) {
char buf[255];

- snprintf(buf, sizeof(buf),
+ scnprintf(buf, sizeof(buf),
"Undefined label %s",
cur_instr->patch_label->name);
stop(buf, EX_DATAERR);
--
2.43.0.594.gd9cf4e227d-goog