Commit dda0b386 authored by Vasiliy Kulikov's avatar Vasiliy Kulikov Committed by David S. Miller
Browse files

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 <>
Signed-off-by: default avatarDavid S. Miller <>
parent 9ea19481
......@@ -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 */
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