[PATCH v2] iproute2: lib/utils.c bug fixes

[Dash Four <mr.dash.four@googlemail.com>]

This patch fixes the following 3 bugs in get_u32/get_u64 functions:

  1. On 32-bit systems, get_u32 could not detect an overflow.
     get_u32(&l, "4294967296", 10) always returned 4294967295
     (ULONG_MAX on 32-bit systems).

  2. get_u64(&ll, "4294967295", 10) was returning an error where
     it shouldn't have (4294967295 is perfectly legitimate value for
     unsigned long long).

  3. get_u64 couldn't detect an overflow errors (arg > ULLONG_MAX)

Changelog:

v2 - Dropped name title from Developer Certificate of Origin

Signed-off-by: Dash Four <mr.dash.four@googlemail.com>
---
  lib/utils.c |    8 ++++++--
  1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/utils.c b/lib/utils.c
index 5bcdbcf..aeee8f1 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -149,10 +149,12 @@ int get_u64(__u64 *val, const char *arg, int base)
  	unsigned long long res;
  	char *ptr;

+	errno = 0;
+
  	if (!arg || !*arg)
  		return -1;
  	res = strtoull(arg, &ptr, base);
-	if (!ptr || ptr == arg || *ptr || res == 0xFFFFFFFFULL)
+	if (!ptr || ptr == arg || *ptr || (res == ULLONG_MAX && errno == ERANGE))
   		return -1;
   	*val = res;
   	return 0;
@@ -163,10 +165,12 @@ int get_u32(__u32 *val, const char *arg, int base)
  	unsigned long res;
  	char *ptr;

+	errno = 0;
+
  	if (!arg || !*arg)
  		return -1;
  	res = strtoul(arg, &ptr, base);
-	if (!ptr || ptr == arg || *ptr || res > 0xFFFFFFFFUL)
+	if (!ptr || ptr == arg || *ptr || res > 0xFFFFFFFFUL || errno == ERANGE)
  		return -1;
  	*val = res;
  	return 0;