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Subject[PATCH] scsi: qla2xxx/qla_attr.c: fix undefined behavior in using snprintf
Date
The original code
snprintf(buf, PAGE_SIZE, "%s\n", buf);
uses buf as both source and destination string, which is undefined behavior
based on C11:
If copying takes place between objects
that overlap, the behavior is undefined.

Signed-off-by: Cong Ding <dinggnu@gmail.com>
---
drivers/scsi/qla2xxx/qla_attr.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/qla2xxx/qla_attr.c b/drivers/scsi/qla2xxx/qla_attr.c
index 83d7984..ded7383 100644
--- a/drivers/scsi/qla2xxx/qla_attr.c
+++ b/drivers/scsi/qla2xxx/qla_attr.c
@@ -887,10 +887,16 @@ qla2x00_serial_num_show(struct device *dev, struct device_attribute *attr,
scsi_qla_host_t *vha = shost_priv(class_to_shost(dev));
struct qla_hw_data *ha = vha->hw;
uint32_t sn;
+ ssize_t bn;

if (IS_FWI2_CAPABLE(ha)) {
qla2xxx_get_vpd_field(vha, "SN", buf, PAGE_SIZE);
- return snprintf(buf, PAGE_SIZE, "%s\n", buf);
+ bn = strlen(buf);
+ if (bn < PAGE_SIZE - 1) {
+ buf[bn] = '\n';
+ buf[bn + 1] = '\0';
+ }
+ return bn + 1;
}

sn = ((ha->serial0 & 0x1f) << 16) | (ha->serial2 << 8) | ha->serial1;
--
1.7.9.5


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