From 21780f89d65837e23fef825c79aa836c1cb3a8e9 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Tue, 8 Nov 2022 16:11:08 +0200 Subject: mac_pton: Don't access memory over expected length The strlen() may go too far when estimating the length of the given string. In some cases it may go over the boundary and crash the system which is the case according to the commit 13a55372b64e ("ARM: orion5x: Revert commit 4904dbda41c8."). Rectify this by switching to strnlen() for the expected maximum length of the string. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20221108141108.62974-1-andriy.shevchenko@linux.intel.com Signed-off-by: Jakub Kicinski --- lib/net_utils.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/lib/net_utils.c b/lib/net_utils.c index af525353395d..c17201df3d08 100644 --- a/lib/net_utils.c +++ b/lib/net_utils.c @@ -6,10 +6,11 @@ bool mac_pton(const char *s, u8 *mac) { + size_t maxlen = 3 * ETH_ALEN - 1; int i; /* XX:XX:XX:XX:XX:XX */ - if (strlen(s) < 3 * ETH_ALEN - 1) + if (strnlen(s, maxlen) < maxlen) return false; /* Don't dirty result unless string is valid MAC. */ -- cgit v1.2.3-59-g8ed1b