Resident Evil 6 is an installment in the survival horror series by Capcom. Its status as a survival horror game is disputed, but that is far from the domain of this article. This is, after all, not a debate forum, but a knife database.
Leon Scott Kennedy uses an Ontario Knife Company (OKC) SP6 fighting knife under the "Survival Knife" designation. There do not appear to be any special customizations, although the detail of the knife's model does not appear to match that of its real-world counterpart by a longshot.
Chris Redfield's combat knife appears to be a 10-inch variant of the Kershaw Camp Knife, with a few customizations. The most noticeable being the desert-tan coating of the blade. Also among the customizations is a blood groove and serrations on the lower half of the edge.
Ironically, though the game refers to the knives as the survival knife and the combat knife, the roles of the blades they appear based on is actually reversed. The Ontario is a blade used for combat as a primary edged weapon, while the Kershaw is a knife meant for use in camping tasks.