From: Brian C Tracy <brian.tracy33@xxxxxxxxx>
Add a new fuzz target that exercises the parsing of git configs.
The existing git_config_from_mem function is a perfect entry point
for fuzzing as it exercises the same code paths as the rest of the
config parsing functions and offers an easily fuzzable interface.
Config parsing is a useful thing to fuzz because it operates on user
controlled data and is a central component of many git operations.
Signed-off-by: Brian C Tracy <brian.tracy33@xxxxxxxxx>
---
fuzz: add fuzzer for config parsing
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1692%2Fbriantracy%2Fconfig-fuzzer-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1692/briantracy/config-fuzzer-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/1692
Range-diff vs v1:
1: a43a2e3a07c ! 1: be6aa5efb1c fuzz: add fuzzer for config parsing
@@ Commit message
Signed-off-by: Brian C Tracy <brian.tracy33@xxxxxxxxx>
## Makefile ##
-@@ Makefile: FUZZ_OBJS += oss-fuzz/fuzz-commit-graph.o
+@@ Makefile: ETAGS_TARGET = TAGS
+ # runs in the future.
+ FUZZ_OBJS += oss-fuzz/dummy-cmd-main.o
+ FUZZ_OBJS += oss-fuzz/fuzz-commit-graph.o
++FUZZ_OBJS += oss-fuzz/fuzz-config.o
FUZZ_OBJS += oss-fuzz/fuzz-date.o
FUZZ_OBJS += oss-fuzz/fuzz-pack-headers.o
FUZZ_OBJS += oss-fuzz/fuzz-pack-idx.o
-+FUZZ_OBJS += oss-fuzz/fuzz-config.o
- .PHONY: fuzz-objs
- fuzz-objs: $(FUZZ_OBJS)
-
## ci/run-build-and-minimal-fuzzers.sh ##
@@ ci/run-build-and-minimal-fuzzers.sh: group "Build fuzzers" make \
@@ ci/run-build-and-minimal-fuzzers.sh: group "Build fuzzers" make \
fuzz-all
-for fuzzer in commit-graph date pack-headers pack-idx ; do
-+for fuzzer in commit-graph date pack-headers pack-idx config ; do
++for fuzzer in commit-graph config date pack-headers pack-idx ; do
begin_group "fuzz-$fuzzer"
./oss-fuzz/fuzz-$fuzzer -verbosity=0 -runs=1 || exit 1
end_group "fuzz-$fuzzer"
## oss-fuzz/.gitignore ##
-@@ oss-fuzz/.gitignore: fuzz-commit-graph
+@@
+ fuzz-commit-graph
++fuzz-config
fuzz-date
fuzz-pack-headers
fuzz-pack-idx
-+fuzz-config
## oss-fuzz/fuzz-config.c (new) ##
@@
+#include "git-compat-util.h"
+#include "config.h"
+
-+#include <stdio.h>
-+#include <string.h>
-+
+int LLVMFuzzerTestOneInput(const uint8_t *, size_t);
+static int config_parser_callback(const char *, const char *,
+ const struct config_context *, void *);
@@ oss-fuzz/fuzz-config.c (new)
+ const struct config_context *ctx UNUSED,
+ void *data UNUSED)
+{
-+ /* Visit every byte of memory we are given to make sure the parser
-+ * gave it to us appropriately. Ensure a return of 0 to indicate
-+ * success so the parsing continues. */
-+ int c = strlen(key);
++ /*
++ * Visit every byte of memory we are given to make sure the parser
++ * gave it to us appropriately. We need to unconditionally return 0,
++ * but we also want to prevent the strlen from being optimized away.
++ */
++ size_t c = strlen(key);
++
+ if (value)
+ c += strlen(value);
-+ return c < 0;
++ return c == SIZE_MAX;
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, const size_t size)
+{
+ struct config_options config_opts = { 0 };
++
+ config_opts.error_action = CONFIG_ERROR_SILENT;
+ git_config_from_mem(config_parser_callback, CONFIG_ORIGIN_BLOB,
+ "fuzztest-config", (const char *)data, size, NULL,
Makefile | 1 +
ci/run-build-and-minimal-fuzzers.sh | 2 +-
oss-fuzz/.gitignore | 1 +
oss-fuzz/fuzz-config.c | 33 +++++++++++++++++++++++++++++
4 files changed, 36 insertions(+), 1 deletion(-)
create mode 100644 oss-fuzz/fuzz-config.c
diff --git a/Makefile b/Makefile
index 4e255c81f22..af32028b18f 100644
--- a/Makefile
+++ b/Makefile
@@ -757,6 +757,7 @@ ETAGS_TARGET = TAGS
# runs in the future.
FUZZ_OBJS += oss-fuzz/dummy-cmd-main.o
FUZZ_OBJS += oss-fuzz/fuzz-commit-graph.o
+FUZZ_OBJS += oss-fuzz/fuzz-config.o
FUZZ_OBJS += oss-fuzz/fuzz-date.o
FUZZ_OBJS += oss-fuzz/fuzz-pack-headers.o
FUZZ_OBJS += oss-fuzz/fuzz-pack-idx.o
diff --git a/ci/run-build-and-minimal-fuzzers.sh b/ci/run-build-and-minimal-fuzzers.sh
index 8ba486f6598..a51076d18df 100755
--- a/ci/run-build-and-minimal-fuzzers.sh
+++ b/ci/run-build-and-minimal-fuzzers.sh
@@ -12,7 +12,7 @@ group "Build fuzzers" make \
LIB_FUZZING_ENGINE="-fsanitize=fuzzer,address" \
fuzz-all
-for fuzzer in commit-graph date pack-headers pack-idx ; do
+for fuzzer in commit-graph config date pack-headers pack-idx ; do
begin_group "fuzz-$fuzzer"
./oss-fuzz/fuzz-$fuzzer -verbosity=0 -runs=1 || exit 1
end_group "fuzz-$fuzzer"
diff --git a/oss-fuzz/.gitignore b/oss-fuzz/.gitignore
index 5b954088254..a877c11f42b 100644
--- a/oss-fuzz/.gitignore
+++ b/oss-fuzz/.gitignore
@@ -1,4 +1,5 @@
fuzz-commit-graph
+fuzz-config
fuzz-date
fuzz-pack-headers
fuzz-pack-idx
diff --git a/oss-fuzz/fuzz-config.c b/oss-fuzz/fuzz-config.c
new file mode 100644
index 00000000000..94027f5b97e
--- /dev/null
+++ b/oss-fuzz/fuzz-config.c
@@ -0,0 +1,33 @@
+#include "git-compat-util.h"
+#include "config.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *, size_t);
+static int config_parser_callback(const char *, const char *,
+ const struct config_context *, void *);
+
+static int config_parser_callback(const char *key, const char *value,
+ const struct config_context *ctx UNUSED,
+ void *data UNUSED)
+{
+ /*
+ * Visit every byte of memory we are given to make sure the parser
+ * gave it to us appropriately. We need to unconditionally return 0,
+ * but we also want to prevent the strlen from being optimized away.
+ */
+ size_t c = strlen(key);
+
+ if (value)
+ c += strlen(value);
+ return c == SIZE_MAX;
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, const size_t size)
+{
+ struct config_options config_opts = { 0 };
+
+ config_opts.error_action = CONFIG_ERROR_SILENT;
+ git_config_from_mem(config_parser_callback, CONFIG_ORIGIN_BLOB,
+ "fuzztest-config", (const char *)data, size, NULL,
+ CONFIG_SCOPE_UNKNOWN, &config_opts);
+ return 0;
+}
base-commit: 945115026aa63df4ab849ab14a04da31623abece
--
gitgitgadget
