go.mod: add go-fuzz-build

Otherwise go-fuzz-build now fails with:

+ go-fuzz-build -libfuzzer -func FuzzDeserialize -o fuzzer.a ./prog/test
-: cannot find package "." in:
	/syzkaller/gopath/src/github.com/google/syzkaller/vendor/github.com/dvyukov/go-fuzz/go-fuzz-dep

2 files changed, 5 insertions, 5 deletions

diff --git a/tools/docker/env/Dockerfile b/tools/docker/env/Dockerfile
index 87184f84a..c1152a9a6 100644
--- a/tools/docker/env/Dockerfile
+++ b/tools/docker/env/Dockerfile
@@ -2,7 +2,7 @@
 # Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
 
 # The image provides dev environment suitable for syzkaller development/testing.
-# It includes Go toolchain, C/C++ cross-compilers and go-fuzz.
+# It includes Go toolchain and C/C++ cross-compilers.
 
 # The image is available as gcr.io/syzkaller/env.
 
@@ -36,9 +36,6 @@ RUN curl https://dl.google.com/go/go1.14.2.linux-amd64.tar.gz | tar -C /usr/loca
 ENV PATH /usr/local/go/bin:/gopath/bin:$PATH
 ENV GOPATH /gopath
 
-# For go-fuzz we also need sources (go-fuzz-dep).
-RUN go get github.com/dvyukov/go-fuzz/go-fuzz github.com/dvyukov/go-fuzz/go-fuzz-build
-
 # Pre-create dirs for syz-dock.
 # This is necessary to make docker work with the current user,
 # otherwise --volume will create these dirs under root and then
diff --git a/tools/fuzzit.sh b/tools/fuzzit.sh
index a056b7c3a..780ce4db5 100755
--- a/tools/fuzzit.sh
+++ b/tools/fuzzit.sh
@@ -7,13 +7,16 @@
 
 set -eux
 export TYPE="${1}"
+export GOBIN=$(realpath .)/bin
 
 function target {
-	go-fuzz-build -libfuzzer -func $3 -o fuzzer.a $2
+	bin/go-fuzz-build -libfuzzer -func $3 -o fuzzer.a $2
 	clang -fsanitize=fuzzer fuzzer.a -o fuzzer
 	./fuzzit create job --type "${TYPE}" --branch ${GITHUB_REF#refs/heads/} --revision ${GITHUB_SHA} syzkaller/$1 ./fuzzer
 }
 
+go install github.com/dvyukov/go-fuzz/go-fuzz-build
+
 curl -L --output fuzzit https://github.com/fuzzitdev/fuzzit/releases/download/v2.4.77/fuzzit_Linux_x86_64
 chmod a+x fuzzit