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

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  [PATCH] ipr: fix out-of-bounds null overwrite Insu Yun <wuninsu@gmail.com> - 2016-01-06 05:20 +0100
    RE: [PATCH] ipr: fix out-of-bounds null overwrite "Seymour, Shane M" <shane.seymour@hpe.com> - 2016-01-06 06:10 +0100

#1302389 — [PATCH] 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 | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 536cd5a..b7c3b1a 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -4009,7 +4009,6 @@ static ssize_t ipr_store_update_fw(struct device *dev,
 		return -EACCES;
 
 	len = snprintf(fname, 99, "%s", buf);
-	fname[len-1] = '\0';
 
 	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

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#1302398

> 	len = snprintf(fname, 99, "%s", buf);
> -	fname[len-1] = '\0';

Since it appears that's the only time len is actually used in that function can
you please remove the variable len completely as part of the patch?
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