__dev_alloc_name is called from the public (and exported) dev_alloc_name(), so we don't have a guarantee that strlen(name) is at most IFNAMSIZ. If somebody manages to get __dev_alloc_name called with a % char beyond the 31st character, we'd be making a snprintf() call that will very easily crash the kernel (using an appropriate %p extension, we'll likely dereference some completely bogus pointer). In the normal case where strlen() is sane, we don't even save anything by limiting to IFNAMSIZ, so just use strchr(). Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: David S. Miller <davem@davemloft.net>