From: Andy Shevchenko Date: Tue, 8 Nov 2022 14:11:08 +0000 (+0200) Subject: mac_pton: Don't access memory over expected length X-Git-Tag: v6.2-rc1~99^2~247 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=21780f89d65837e23fef825c79aa836c1cb3a8e9;p=thirdparty%2Fkernel%2Flinux.git 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 --- diff --git a/lib/net_utils.c b/lib/net_utils.c index af525353395d6..c17201df3d081 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. */