| Message ID | 1289754368-31660-1-git-send-email-segoon@openwall.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Vasiliy Kulikov <segoon@openwall.com> Date: Sun, 14 Nov 2010 20:06:08 +0300 > 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 <segoon@openwall.com> Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/ipv4/tcp_probe.c b/net/ipv4/tcp_probe.c index 6211e21..3b7bf19 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 */
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 <segoon@openwall.com> --- Compile tested. Format length: 20 for '%lu' 1 for '.' 9 for '%09lu' 1 for ' ' 15 for '%pI4' 1 for ':' 10 for '%u' 1 for ' ' 15 for '%pI4' 1 for ':' 10 for '%u' 1 for ' ' 11 for '%d' 1 for ' ' 10 for '%#x' 1 for ' ' 10 for '%#x' 1 for ' ' 10 for '%u' 1 for ' ' 10 for '%u' 1 for ' ' 10 for '%u' 1 for ' ' 10 for '%u' 1 for '\n' 163 for '%lu.%09lu %pI4:%u %pI4:%u %d %#x %#x %u %u %u %u\n' net/ipv4/tcp_probe.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)