[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 6/8] tools/insn-fuzz: Accept fuzzing input on stdin
This is rather faster for afl-fuzz to arrange than using an explicit file parameter. Also update the README to recommend using a tmpfs for findings_dir which reduces disk load and is more performant. Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> --- CC: Jan Beulich <JBeulich@xxxxxxxx> CC: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx> CC: Wei Liu <wei.liu2@xxxxxxxxxx> --- tools/fuzz/README.afl | 7 ++++-- tools/fuzz/x86_instruction_emulator/afl-harness.c | 29 ++++++++++++++--------- 2 files changed, 23 insertions(+), 13 deletions(-) diff --git a/tools/fuzz/README.afl b/tools/fuzz/README.afl index 357c3c8..c5f749a 100644 --- a/tools/fuzz/README.afl +++ b/tools/fuzz/README.afl @@ -25,8 +25,11 @@ Use the x86 instruction emulator fuzzer as an example. $ dd if=/dev/urandom of=testcase_dir/rand.bin \ bs=`./afl-harness --min-input-size` count=1 +3a. use a tmpfs for findings_dir (Perf improvement and reduced disk load) + $ mkdir findings_dir + $ mount -t tmpfs -o size=512M tmpfs findings_dir + 4. run the fuzzer with AFL: - $ $AFLPATH/afl-fuzz -m none -t 1000 -i testcase_dir -o findings_dir -- \ - ./afl-harness @@ + $ $AFLPATH/afl-fuzz -t 1000 -i testcase_dir -o findings_dir -- ./afl-harness Please see AFL documentation for more information. diff --git a/tools/fuzz/x86_instruction_emulator/afl-harness.c b/tools/fuzz/x86_instruction_emulator/afl-harness.c index 102566c..89d8605 100644 --- a/tools/fuzz/x86_instruction_emulator/afl-harness.c +++ b/tools/fuzz/x86_instruction_emulator/afl-harness.c @@ -14,7 +14,7 @@ static uint8_t input[INPUT_SIZE]; int main(int argc, char **argv) { size_t size; - FILE *fp; + FILE *fp = NULL; setbuf(stdout, NULL); @@ -40,6 +40,7 @@ int main(int argc, char **argv) break; case '?': + usage: printf("Usage: %s $FILE | [--min-input-size]\n", argv[0]); exit(-1); break; @@ -51,17 +52,19 @@ int main(int argc, char **argv) } } - if ( optind != (argc - 1) ) - { - printf("Expecting only one argument\n"); - exit(-1); - } + if ( optind == argc ) /* No positional parameters. Use stdin. */ + fp = stdin; + else if ( optind != (argc - 1) ) + goto usage; - fp = fopen(argv[1], "rb"); - if ( fp == NULL ) + if ( fp != stdin ) /* If not using stdin, open the provided file. */ { - perror("fopen"); - exit(-1); + fp = fopen(argv[optind], "rb"); + if ( fp == NULL ) + { + perror("fopen"); + exit(-1); + } } size = fread(input, 1, INPUT_SIZE, fp); @@ -78,7 +81,11 @@ int main(int argc, char **argv) exit(-1); } - fclose(fp); + if ( fp != stdin ) + { + fclose(fp); + fp = NULL; + } LLVMFuzzerTestOneInput(input, size); -- 2.1.4 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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