fuzz-tokenize: Slice bounds out of range in caddyfile.(*lexer).next

[mohammed90]

Reported at: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=61620

Detailed Report: https://oss-fuzz.com/testcase?key=4886037758083072

Project: caddy
Fuzzing Engine: libFuzzer
Fuzz Target: fuzz-tokenize
Job Type: libfuzzer_asan_caddy
Platform Id: linux

Crash Type: Slice bounds out of range
Crash Address:
Crash State:
caddyfile.(*lexer).next
caddyfile.Tokenize

Sanitizer: address (ASAN)

Regressed: https://oss-fuzz.com/revisions?job=libfuzzer_asan_caddy&range=202308190620:202308200626

Reproducer Testcase: https://oss-fuzz.com/download?testcase_id=4886037758083072

Stack trace:

goroutine 17 [running, locked to thread]:
--
  | github.com/caddyserver/caddy/v2/caddyconfig/caddyfile.(*lexer).next(0x10c00007ad40)
  | github.com/caddyserver/caddy/v2/caddyconfig/caddyfile/lexer.go:158 +0x1cf5
  | github.com/caddyserver/caddy/v2/caddyconfig/caddyfile.Tokenize({0x6020000000b0, 0x3, 0x3}, {0xeffca7, 0x9})
  | github.com/caddyserver/caddy/v2/caddyconfig/caddyfile/lexer.go:63 +0x1b1
  | github.com/caddyserver/caddy/v2/caddyconfig/caddyfile.FuzzTokenize({0x6020000000b0?, 0x0?, 0x1?})
  | github.com/caddyserver/caddy/v2/caddyconfig/caddyfile/lexer_fuzz.go:20 +0x4b

clusterfuzz-testcase-minimized-fuzz-tokenize-4886037758083072.txt