| Message ID | 20240208084512.3803250-9-lee@kernel.org (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | scsi: Replace {v}snprintf() variants with safer alternatives | expand |
On Thu, Feb 08, 2024 at 08:44:20AM +0000, Lee Jones wrote: > 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> Reviewed-by: Kees Cook <keescook@chromium.org>
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);
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(-)