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From: Lee Jones <lee@kernel.org>
To: lee@kernel.org
Cc: linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org,
	Hannes Reinecke <hare@suse.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	linux-scsi@vger.kernel.org
Subject: [PATCH 08/10] scsi: aic7xxx: aicasm: Replace snprintf() with the safer scnprintf() variant
Date: Thu,  8 Feb 2024 08:44:20 +0000	[thread overview]
Message-ID: <20240208084512.3803250-9-lee@kernel.org> (raw)
In-Reply-To: <20240208084512.3803250-1-lee@kernel.org>

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


  parent reply	other threads:[~2024-02-08  8:45 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-08  8:44 [PATCH 00/10] scsi: Replace {v}snprintf() variants with safer alternatives Lee Jones
2024-02-08  8:44 ` [PATCH 01/10] scsi: 3w-xxxx: Trivial: Remove trailing whitespace Lee Jones
2024-02-10  6:58   ` Kees Cook
2024-02-08  8:44 ` [PATCH 02/10] scsi: 53c700: " Lee Jones
2024-02-10  6:58   ` Kees Cook
2024-02-08  8:44 ` [PATCH 03/10] scsi: NCR5380: Replace snprintf() with the safer scnprintf() variant Lee Jones
2024-02-08 10:22   ` Geert Uytterhoeven
2024-02-08 10:29     ` Lee Jones
2024-02-10  9:32       ` Finn Thain
2024-02-10 12:56       ` James Bottomley
2024-02-19 15:23         ` Lee Jones
2024-02-19 16:25           ` James Bottomley
2024-02-20  8:28             ` Lee Jones
2024-02-19 21:30           ` Kees Cook
2024-02-20  8:24             ` Lee Jones
2024-02-10  7:14   ` Kees Cook
2024-02-08  8:44 ` [PATCH 04/10] scsi: aacraid: linit: Remove snprintf() from sysfs call-backs and replace with sysfs_emit() Lee Jones
2024-02-10  7:00   ` Kees Cook
2024-02-08  8:44 ` [PATCH 05/10] scsi: aacraid: linit: Replace snprintf() with the safer scnprintf() variant Lee Jones
2024-02-10  7:03   ` Kees Cook
2024-02-08  8:44 ` [PATCH 06/10] scsi: aha1542: " Lee Jones
2024-02-10  7:06   ` Kees Cook
2024-02-08  8:44 ` [PATCH 07/10] scsi: aic7xxx: aicasm: Trivial: Remove trailing whitespace Lee Jones
2024-02-10  6:58   ` Kees Cook
2024-02-08  8:44 ` Lee Jones [this message]
2024-02-10  7:06   ` [PATCH 08/10] scsi: aic7xxx: aicasm: Replace snprintf() with the safer scnprintf() variant Kees Cook
2024-02-08  8:44 ` [PATCH 09/10] scsi: aic94xx: Remove snprintf() from sysfs call-backs and replace with sysfs_emit() Lee Jones
2024-02-10  7:13   ` Kees Cook
2024-02-08  8:44 ` [PATCH 10/10] scsi: arcmsr: " Lee Jones
2024-02-10  7:13   ` Kees Cook
2024-02-08 17:40 ` [PATCH 00/10] scsi: Replace {v}snprintf() variants with safer alternatives Bart Van Assche
2024-02-08 17:49   ` Lee Jones
2024-02-10  6:56     ` .mailmap support for removals (was Re: [PATCH 00/10] scsi: Replace {v}snprintf() variants with safer alternatives) Kees Cook
2024-02-10 22:56       ` Joe Perches

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