SNAFU = Situation Normal, All Fouled Up
Yep, the voice is Mel Blanc! (Bugs Bunny, Daffy Duck, Sylvester, Tweety and loads more).
Private Snafu is the title character of a series of blackandwhite American instructional cartoon shorts, ironic and humorous in tone, that were produced between 1943 and 1945 during World War II. The films were designed to instruct service personnel about security, proper sanitation habits, booby traps and other military subjects, and to improve troop morale.
The series was directed by Chuck Jones and other prominent Hollywood animators, and the voice of Private Snafu was performed by Mel Blanc.