[U-Boot] [RFC PATCH v2 03/11] 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>
---

Changes in v2:
- restore some lazy parsing behavior that the tftpboot command relied on.

 lib/net_utils.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/lib/net_utils.c b/lib/net_utils.c
index cfae842..f148b8a 100644
--- a/lib/net_utils.c
+++ b/lib/net_utils.c
@@ -24,11 +24,16 @@ 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
+			break;
 	}
 
 	addr.s_addr = htonl(addr.s_addr);
-- 
2.5.3