From dda0b38692a7298f433b92b1329867b1ecabb4bb Mon Sep 17 00:00:00 2001 From: Vasiliy Kulikov Date: Sun, 14 Nov 2010 07:06:08 +0000 Subject: [PATCH] net: ipv4: tcp_probe: cleanup snprintf() use snprintf() returns number of bytes that were copied if there is no overflow. This code uses return value as number of copied bytes. Theoretically format string '%lu.%09lu %pI4:%u %pI4:%u %d %#x %#x %u %u %u %u\n' may be expanded up to 163 bytes. In reality tv.tv_sec is just few bytes instead of 20, 2 ports are just 5 bytes each instead of 10, length is 5 bytes instead of 10. The rest is an unstrusted input. Theoretically if tv_sec is big then copy_to_user() would overflow tbuf. tbuf was increased to fit in 163 bytes. snprintf() is used to follow return value semantic. Signed-off-by: Vasiliy Kulikov Signed-off-by: David S. Miller --- net/ipv4/tcp_probe.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp_probe.c b/net/ipv4/tcp_probe.c index 6211e2114173..85ee7eb7e38e 100644 --- a/net/ipv4/tcp_probe.c +++ b/net/ipv4/tcp_probe.c @@ -154,7 +154,7 @@ static int tcpprobe_sprint(char *tbuf, int n) struct timespec tv = ktime_to_timespec(ktime_sub(p->tstamp, tcp_probe.start)); - return snprintf(tbuf, n, + return scnprintf(tbuf, n, "%lu.%09lu %pI4:%u %pI4:%u %d %#x %#x %u %u %u %u\n", (unsigned long) tv.tv_sec, (unsigned long) tv.tv_nsec, @@ -174,7 +174,7 @@ static ssize_t tcpprobe_read(struct file *file, char __user *buf, return -EINVAL; while (cnt < len) { - char tbuf[128]; + char tbuf[164]; int width; /* Wait for data in buffer */ -- 2.20.1