[PATCH] Cleanup: snprintf() always NUL-terminates: depend on it

From: Giel van Schijndel
Date: Sun Jan 04 2015 - 14:11:41 EST


Especially since one very strange piece of code seems to be written in
such a way that a NUL needs to be placed where a NUL is present already.
The author probably meant to fill the last byte of the buffer with a NUL
instead. But regardless of that: that isn't necessary since snprintf()
already guarantees NUL termination for buffers sizes > 0 and <= INT_MAX.
---
drivers/scsi/ipr.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index df4e27c..b49fe45 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -3990,7 +3990,6 @@ 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);
@@ -9358,13 +9357,12 @@ static int ipr_enable_msi(struct ipr_ioa_cfg *ioa_cfg)

static void name_msi_vectors(struct ipr_ioa_cfg *ioa_cfg)
{
- int vec_idx, n = sizeof(ioa_cfg->vectors_info[0].desc) - 1;
+ int vec_idx;

for (vec_idx = 0; vec_idx < ioa_cfg->nvectors; vec_idx++) {
- snprintf(ioa_cfg->vectors_info[vec_idx].desc, n,
+ snprintf(ioa_cfg->vectors_info[vec_idx].desc,
+ sizeof(ioa_cfg->vectors_info[vec_idx].desc),
"host%d-%d", ioa_cfg->host->host_no, vec_idx);
- ioa_cfg->vectors_info[vec_idx].
- desc[strlen(ioa_cfg->vectors_info[vec_idx].desc)] = 0;
}
}

--
2.1.4

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