net: netdevsim: Use scnprintf() for avoiding potential buffer overflow

Since snprintf() returns the would-be-output size instead of the
actual output size, the succeeding calls may go beyond the given
buffer limit.  Fix it by replacing with scnprintf().

Cc: "David S . Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Takashi Iwai 2020-03-15 10:35:03 +01:00 committed by David S. Miller
parent 5e892880e1
commit 2da222f612

View File

@ -29,9 +29,9 @@ static ssize_t nsim_dbg_netdev_ops_read(struct file *filp,
return -ENOMEM;
p = buf;
p += snprintf(p, bufsize - (p - buf),
"SA count=%u tx=%u\n",
ipsec->count, ipsec->tx);
p += scnprintf(p, bufsize - (p - buf),
"SA count=%u tx=%u\n",
ipsec->count, ipsec->tx);
for (i = 0; i < NSIM_IPSEC_MAX_SA_COUNT; i++) {
struct nsim_sa *sap = &ipsec->sa[i];
@ -39,18 +39,18 @@ static ssize_t nsim_dbg_netdev_ops_read(struct file *filp,
if (!sap->used)
continue;
p += snprintf(p, bufsize - (p - buf),
"sa[%i] %cx ipaddr=0x%08x %08x %08x %08x\n",
i, (sap->rx ? 'r' : 't'), sap->ipaddr[0],
sap->ipaddr[1], sap->ipaddr[2], sap->ipaddr[3]);
p += snprintf(p, bufsize - (p - buf),
"sa[%i] spi=0x%08x proto=0x%x salt=0x%08x crypt=%d\n",
i, be32_to_cpu(sap->xs->id.spi),
sap->xs->id.proto, sap->salt, sap->crypt);
p += snprintf(p, bufsize - (p - buf),
"sa[%i] key=0x%08x %08x %08x %08x\n",
i, sap->key[0], sap->key[1],
sap->key[2], sap->key[3]);
p += scnprintf(p, bufsize - (p - buf),
"sa[%i] %cx ipaddr=0x%08x %08x %08x %08x\n",
i, (sap->rx ? 'r' : 't'), sap->ipaddr[0],
sap->ipaddr[1], sap->ipaddr[2], sap->ipaddr[3]);
p += scnprintf(p, bufsize - (p - buf),
"sa[%i] spi=0x%08x proto=0x%x salt=0x%08x crypt=%d\n",
i, be32_to_cpu(sap->xs->id.spi),
sap->xs->id.proto, sap->salt, sap->crypt);
p += scnprintf(p, bufsize - (p - buf),
"sa[%i] key=0x%08x %08x %08x %08x\n",
i, sap->key[0], sap->key[1],
sap->key[2], sap->key[3]);
}
len = simple_read_from_buffer(buffer, count, ppos, buf, p - buf);