[U-Boot] [RFC PATCH 3/8] lib: net_utils: make string_to_ip stricter

[Chris Packham]

Previously values greater than 255 were implicitly truncated. Add some
stricter checking to reject addresses with components >255.

With the input "1234192.168.1.1" the old behaviour would truncate the
address to 192.168.1.1. New behaviour rejects the string outright and
returns 0.0.0.0, which for the purposes of IP addresses can be
considered an error.

Signed-off-by: Chris Packham <judge.packham at gmail.com>
---

 lib/net_utils.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/lib/net_utils.c b/lib/net_utils.c
index cfae842..0fca54d 100644
--- a/lib/net_utils.c
+++ b/lib/net_utils.c
@@ -24,10 +24,19 @@ struct in_addr string_to_ip(const char *s)
 
 	for (addr.s_addr = 0, i = 0; i < 4; ++i) {
 		ulong val = s ? simple_strtoul(s, &e, 10) : 0;
+		if (val > 255) {
+			addr.s_addr = 0;
+			return addr;
+		}
 		addr.s_addr <<= 8;
 		addr.s_addr |= (val & 0xFF);
-		if (s) {
-			s = (*e) ? e+1 : e;
+		if (*e == '.') {
+			s = e + 1;
+		} else if (*e == '\0') {
+			break;
+		} else {
+			addr.s_addr = 0;
+			return addr;
 		}
 	}
 
-- 
2.5.3