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Commit dda0b386 authored by Vasiliy Kulikov's avatar Vasiliy Kulikov Committed by David S. Miller
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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: default avatarVasiliy Kulikov <segoon@openwall.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9ea19481

net/ipv4/tcp_probe.c

+2 −2
Original line number Diff line number Diff line
@@ -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 */