linux-kernel - [PATCH 3.2 41/62] ipr: Fix out-of-bounds null overwrite

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 29 Mar 2016 20:18:22 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:	akpm@...ux-foundation.org, "Shane Seymour" <shane.seymour@....com>,
	"Insu Yun" <wuninsu@...il.com>,
	"Martin K. Petersen" <martin.petersen@...cle.com>
Subject: [PATCH 3.2 41/62] ipr: Fix out-of-bounds null overwrite

3.2.79-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Insu Yun <wuninsu@...il.com>

commit d63c7dd5bcb9441af0526d370c43a65ca2c980d9 upstream.

Return value of snprintf is not bound by size value, 2nd argument.
(https://www.kernel.org/doc/htmldocs/kernel-api/API-snprintf.html).
Return value is number of printed chars, can be larger than 2nd
argument.  Therefore, it can write null byte out of bounds ofbuffer.
Since snprintf puts null, it does not need to put additional null byte.

Signed-off-by: Insu Yun <wuninsu@...il.com>
Reviewed-by: Shane Seymour <shane.seymour@....com>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/scsi/ipr.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -3736,13 +3736,12 @@ static ssize_t ipr_store_update_fw(struc
 	struct ipr_sglist *sglist;
 	char fname[100];
 	char *src;
-	int len, result, dnld_size;
+	int result, dnld_size;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EACCES;
 
-	len = snprintf(fname, 99, "%s", buf);
-	fname[len-1] = '\0';
+	snprintf(fname, sizeof(fname), "%s", buf);
 
 	if(request_firmware(&fw_entry, fname, &ioa_cfg->pdev->dev)) {
 		dev_err(&ioa_cfg->pdev->dev, "Firmware file %s not found\n", fname);