Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1302779 > unrolled thread

[PATCH v2] ipr: fix out-of-bounds null overwrite

Back to article view | Back to linux.kernel

Contents

  [PATCH v2] ipr: fix out-of-bounds null overwrite Insu Yun <wuninsu@gmail.com> - 2016-01-06 15:00 +0100
    Re: [PATCH v2] ipr: fix out-of-bounds null overwrite "Matthew R. Ochs" <mrochs@linux.vnet.ibm.com> - 2016-01-06 18:30 +0100

#1302779 — [PATCH v2] ipr: fix out-of-bounds null overwrite

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@gmail.com>
---
 drivers/scsi/ipr.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 536cd5a..caf63f9 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -4003,13 +4003,12 @@ static ssize_t ipr_store_update_fw(struct device *dev,
 	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, 99, "%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);
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [next] | [standalone]

#1302911

On Jan 6, 2016, at 7:53 AM, Insu Yun <wuninsu@gmail.com> wrote:
> 
> 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@gmail.com>
> ---
> drivers/scsi/ipr.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
> index 536cd5a..caf63f9 100644
> --- a/drivers/scsi/ipr.c
> +++ b/drivers/scsi/ipr.c
> @@ -4003,13 +4003,12 @@ static ssize_t ipr_store_update_fw(struct device *dev,
> 	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, 99, "%s", buf);

Changing the 99 to sizeof(fname) as part of this change would also
make for cleaner code in my opinion. Will leave it up to you if you'd
like to do a v3.

Reviewed-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com> 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web