diff options
-rwxr-xr-x | afl-cmin | 3 | ||||
-rw-r--r-- | docs/env_variables.md | 15 | ||||
-rw-r--r-- | include/afl-fuzz.h | 5 | ||||
-rw-r--r-- | include/common.h | 16 | ||||
-rw-r--r-- | include/envs.h | 2 | ||||
-rw-r--r-- | include/forkserver.h | 5 | ||||
-rw-r--r-- | instrumentation/afl-compiler-rt.o.c | 2 | ||||
-rw-r--r-- | src/afl-analyze.c | 7 | ||||
-rw-r--r-- | src/afl-common.c | 52 | ||||
-rw-r--r-- | src/afl-forkserver.c | 19 | ||||
-rw-r--r-- | src/afl-fuzz-init.c | 1 | ||||
-rw-r--r-- | src/afl-fuzz-state.c | 19 | ||||
-rw-r--r-- | src/afl-fuzz.c | 10 | ||||
-rw-r--r-- | src/afl-showmap.c | 13 | ||||
-rw-r--r-- | src/afl-tmin.c | 10 |
15 files changed, 110 insertions, 69 deletions
diff --git a/afl-cmin b/afl-cmin index 8fe35ced..15b61f89 100755 --- a/afl-cmin +++ b/afl-cmin @@ -123,6 +123,9 @@ function usage() { "AFL_FORKSRV_INIT_TMOUT: time the fuzzer waits for the forkserver to come up\n" \ "AFL_KEEP_TRACES: leave the temporary <out_dir>/.traces directory\n" \ "AFL_KILL_SIGNAL: Signal delivered to child processes on timeout (default: SIGKILL)\n" \ +"AFL_FORK_SERVER_KILL_SIGNAL: Signal delivered to fork server processes on termination\n" \ +" (default: SIGTERM). If this is not set and AFL_KILL_SIGNAL is set,\n" \ +" this will be set to the same value as AFL_KILL_SIGNAL.\n" \ "AFL_NO_FORKSRV: run target via execve instead of using the forkserver\n" \ "AFL_CMIN_ALLOW_ANY: write tuples for crashing inputs also\n" \ "AFL_PATH: path for the afl-showmap binary if not found anywhere in PATH\n" \ diff --git a/docs/env_variables.md b/docs/env_variables.md index 1abe9438..d1c13e15 100644 --- a/docs/env_variables.md +++ b/docs/env_variables.md @@ -409,11 +409,22 @@ checks or alter some of the more exotic semantics of the tool: the afl-fuzz -g/-G command line option to control the minimum/maximum of fuzzing input generated. - - `AFL_KILL_SIGNAL`: Set the signal ID to be delivered to child processes on - timeout. Unless you implement your own targets or instrumentation, you + - `AFL_KILL_SIGNAL`: Set the signal ID to be delivered to child processes + on timeout. Unless you implement your own targets or instrumentation, you likely don't have to set it. By default, on timeout and on exit, `SIGKILL` (`AFL_KILL_SIGNAL=9`) will be delivered to the child. + - `AFL_FORK_SERVER_KILL_SIGNAL`: Set the signal ID to be delivered to the + fork server when AFL++ is terminated. Unless you implement your + fork server, you likely do not have to set it. By default, `SIGTERM` + (`AFL_FORK_SERVER_KILL_SIGNAL=15`) will be delivered to the fork server. + If only `AFL_KILL_SIGNAL` is provided, `AFL_FORK_SERVER_KILL_SIGNAL` will + be set to same value as `AFL_KILL_SIGNAL` to provide backward compatibility. + If `AFL_FORK_SERVER_KILL_SIGNAL` is also set, it takes precedence. + + NOTE: Uncatchable signals, such as `SIGKILL`, cause child processes of + the fork server to be orphaned and leaves them in a zombie state. + - `AFL_MAP_SIZE` sets the size of the shared map that afl-analyze, afl-fuzz, afl-showmap, and afl-tmin create to gather instrumentation data from the target. This must be equal or larger than the size the target was compiled diff --git a/include/afl-fuzz.h b/include/afl-fuzz.h index 23c20cc4..73c3b09f 100644 --- a/include/afl-fuzz.h +++ b/include/afl-fuzz.h @@ -393,8 +393,8 @@ typedef struct afl_env_vars { *afl_hang_tmout, *afl_forksrv_init_tmout, *afl_preload, *afl_max_det_extras, *afl_statsd_host, *afl_statsd_port, *afl_crash_exitcode, *afl_statsd_tags_flavor, *afl_testcache_size, - *afl_testcache_entries, *afl_kill_signal, *afl_target_env, - *afl_persistent_record, *afl_exit_on_time; + *afl_testcache_entries, *afl_child_kill_signal, *afl_fsrv_kill_signal, + *afl_target_env, *afl_persistent_record, *afl_exit_on_time; } afl_env_vars_t; @@ -1268,4 +1268,3 @@ void queue_testcase_store_mem(afl_state_t *afl, struct queue_entry *q, u8 *mem); #endif #endif - diff --git a/include/common.h b/include/common.h index a983bb0e..c1ba0f20 100644 --- a/include/common.h +++ b/include/common.h @@ -32,6 +32,7 @@ #include <unistd.h> #include <sys/time.h> #include <stdbool.h> +#include "forkserver.h" #include "types.h" /* STRINGIFY_VAL_SIZE_MAX will fit all stringify_ strings. */ @@ -67,10 +68,16 @@ u8 *find_binary(u8 *fname); u8 *find_afl_binary(u8 *own_loc, u8 *fname); -/* Parses the kill signal environment variable, FATALs on error. - If the env is not set, sets the env to default_signal for the signal handlers - and returns the default_signal. */ -int parse_afl_kill_signal_env(u8 *afl_kill_signal_env, int default_signal); +/* Parses the (numeric) kill signal environment variable passed + via `numeric_signal_as_str`. + If NULL is passed, the `default_signal` value is returned. + FATALs if `numeric_signal_as_str` is not a valid integer .*/ +int parse_afl_kill_signal(u8 *numeric_signal_as_str, int default_signal); + +/* Configure the signals that are used to kill the forkserver + and the forked childs. If `afl_kill_signal_env` or `afl_fsrv_kill_signal_env` + is NULL, the appropiate values are read from the environment. */ +void configure_afl_kill_signals(afl_forkserver_t *fsrv, char* afl_kill_signal_env, char* afl_fsrv_kill_signal_env); /* Read a bitmap from file fname to memory This is for the -B option again. */ @@ -133,4 +140,3 @@ FILE *create_ffile(u8 *fn); s32 create_file(u8 *fn); #endif - diff --git a/include/envs.h b/include/envs.h index 2204a100..33c09780 100644 --- a/include/envs.h +++ b/include/envs.h @@ -110,6 +110,7 @@ static char *afl_environment_variables[] = { "AFL_INST_RATIO", "AFL_KEEP_TIMEOUTS", "AFL_KILL_SIGNAL", + "AFL_FORK_SERVER_KILL_SIGNAL", "AFL_KEEP_TRACES", "AFL_KEEP_ASSEMBLY", "AFL_LD_HARD_FAIL", @@ -239,4 +240,3 @@ static char *afl_environment_variables[] = { extern char *afl_environment_variables[]; #endif - diff --git a/include/forkserver.h b/include/forkserver.h index 59ce0ee7..bfd441d4 100644 --- a/include/forkserver.h +++ b/include/forkserver.h @@ -163,7 +163,9 @@ typedef struct afl_forkserver { void (*add_extra_func)(void *afl_ptr, u8 *mem, u32 len); - u8 kill_signal; + u8 child_kill_signal; + u8 fsrv_kill_signal; + u8 persistent_mode; #ifdef __linux__ @@ -222,4 +224,3 @@ void afl_fsrv_kill(afl_forkserver_t *fsrv); #endif /* ^RLIMIT_AS */ #endif - diff --git a/instrumentation/afl-compiler-rt.o.c b/instrumentation/afl-compiler-rt.o.c index 20069824..8c09d9d8 100644 --- a/instrumentation/afl-compiler-rt.o.c +++ b/instrumentation/afl-compiler-rt.o.c @@ -159,6 +159,7 @@ static void at_exit(int signal) { if (unlikely(child_pid > 0)) { kill(child_pid, SIGKILL); + waitpid(child_pid, NULL, 0); child_pid = -1; } @@ -2407,4 +2408,3 @@ void __afl_set_persistent_mode(u8 mode) { } #undef write_error - diff --git a/src/afl-analyze.c b/src/afl-analyze.c index a21f014f..d356874d 100644 --- a/src/afl-analyze.c +++ b/src/afl-analyze.c @@ -114,7 +114,7 @@ static void kill_child() { if (fsrv.child_pid > 0) { - kill(fsrv.child_pid, fsrv.kill_signal); + kill(fsrv.child_pid, fsrv.child_kill_signal); fsrv.child_pid = -1; } @@ -1115,8 +1115,8 @@ int main(int argc, char **argv_orig, char **envp) { } - fsrv.kill_signal = - parse_afl_kill_signal_env(getenv("AFL_KILL_SIGNAL"), SIGKILL); + configure_afl_kill_signals(&fsrv, NULL, NULL); + read_initial_file(); (void)check_binary_signatures(fsrv.target_path); @@ -1151,4 +1151,3 @@ int main(int argc, char **argv_orig, char **envp) { exit(0); } - diff --git a/src/afl-common.c b/src/afl-common.c index f3e78ac5..f2934817 100644 --- a/src/afl-common.c +++ b/src/afl-common.c @@ -25,6 +25,7 @@ #include <stdlib.h> #include <stdio.h> +#include "forkserver.h" #ifndef _GNU_SOURCE #define _GNU_SOURCE #endif @@ -47,6 +48,7 @@ #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> +#include <signal.h> u8 be_quiet = 0; u8 *doc_path = ""; @@ -456,37 +458,44 @@ u8 *find_afl_binary(u8 *own_loc, u8 *fname) { } -/* Parses the kill signal environment variable, FATALs on error. - If the env is not set, sets the env to default_signal for the signal handlers - and returns the default_signal. */ -int parse_afl_kill_signal_env(u8 *afl_kill_signal_env, int default_signal) { - if (afl_kill_signal_env && afl_kill_signal_env[0]) { +int parse_afl_kill_signal(u8 *numeric_signal_as_str, int default_signal) { + + if (numeric_signal_as_str && numeric_signal_as_str[0]) { char *endptr; u8 signal_code; - signal_code = (u8)strtoul(afl_kill_signal_env, &endptr, 10); + signal_code = (u8)strtoul(numeric_signal_as_str, &endptr, 10); /* Did we manage to parse the full string? */ - if (*endptr != '\0' || endptr == (char *)afl_kill_signal_env) { - - FATAL("Invalid AFL_KILL_SIGNAL: %s (expected unsigned int)", - afl_kill_signal_env); - + if (*endptr != '\0' || endptr == (char *)numeric_signal_as_str) { + FATAL("Invalid signal name: %s", numeric_signal_as_str); + } else { + return signal_code; } - return signal_code; - - } else { - - char *sigstr = alloc_printf("%d", default_signal); - if (!sigstr) { FATAL("Failed to alloc mem for signal buf"); } + } - /* Set the env for signal handler */ - setenv("AFL_KILL_SIGNAL", sigstr, 1); - free(sigstr); - return default_signal; + return default_signal; +} +void configure_afl_kill_signals(afl_forkserver_t *fsrv, char* afl_kill_signal_env, char* afl_fsrv_kill_signal_env) { + afl_kill_signal_env = afl_kill_signal_env ? + afl_kill_signal_env : getenv("AFL_KILL_SIGNAL"); + afl_fsrv_kill_signal_env = afl_fsrv_kill_signal_env ? + afl_fsrv_kill_signal_env : getenv("AFL_FORK_SERVER_KILL_SIGNAL"); + + fsrv->child_kill_signal = + parse_afl_kill_signal(afl_kill_signal_env, SIGKILL); + + if (afl_kill_signal_env && !afl_fsrv_kill_signal_env) { + /* + Set AFL_FORK_SERVER_KILL_SIGNAL to the value of AFL_KILL_SIGNAL for backwards + compatibility. However, if AFL_FORK_SERVER_KILL_SIGNAL is set, is takes precedence. + */ + afl_fsrv_kill_signal_env = afl_kill_signal_env; } + fsrv->fsrv_kill_signal = + parse_afl_kill_signal(afl_fsrv_kill_signal_env, SIGTERM); } @@ -1253,4 +1262,3 @@ s32 create_file(u8 *fn) { return fd; } - diff --git a/src/afl-forkserver.c b/src/afl-forkserver.c index 628ff590..72db3c2e 100644 --- a/src/afl-forkserver.c +++ b/src/afl-forkserver.c @@ -100,7 +100,7 @@ void afl_fsrv_init(afl_forkserver_t *fsrv) { fsrv->init_tmout = EXEC_TIMEOUT * FORK_WAIT_MULT; fsrv->mem_limit = MEM_LIMIT; fsrv->out_file = NULL; - fsrv->kill_signal = SIGKILL; + fsrv->child_kill_signal = SIGKILL; /* exec related stuff */ fsrv->child_pid = -1; @@ -134,7 +134,7 @@ void afl_fsrv_init_dup(afl_forkserver_t *fsrv_to, afl_forkserver_t *from) { fsrv_to->no_unlink = from->no_unlink; fsrv_to->uses_crash_exitcode = from->uses_crash_exitcode; fsrv_to->crash_exitcode = from->crash_exitcode; - fsrv_to->kill_signal = from->kill_signal; + fsrv_to->child_kill_signal = from->child_kill_signal; fsrv_to->debug = from->debug; // These are forkserver specific. @@ -793,7 +793,7 @@ void afl_fsrv_start(afl_forkserver_t *fsrv, char **argv, s32 tmp_pid = fsrv->fsrv_pid; if (tmp_pid > 0) { - kill(tmp_pid, fsrv->kill_signal); + kill(tmp_pid, fsrv->child_kill_signal); fsrv->fsrv_pid = -1; } @@ -804,7 +804,7 @@ void afl_fsrv_start(afl_forkserver_t *fsrv, char **argv, s32 tmp_pid = fsrv->fsrv_pid; if (tmp_pid > 0) { - kill(tmp_pid, fsrv->kill_signal); + kill(tmp_pid, fsrv->child_kill_signal); fsrv->fsrv_pid = -1; } @@ -1242,11 +1242,11 @@ void afl_fsrv_start(afl_forkserver_t *fsrv, char **argv, void afl_fsrv_kill(afl_forkserver_t *fsrv) { - if (fsrv->child_pid > 0) { kill(fsrv->child_pid, fsrv->kill_signal); } + if (fsrv->child_pid > 0) { kill(fsrv->child_pid, fsrv->child_kill_signal); } if (fsrv->fsrv_pid > 0) { - kill(fsrv->fsrv_pid, fsrv->kill_signal); - if (waitpid(fsrv->fsrv_pid, NULL, 0) <= 0) { WARNF("error waitpid\n"); } + kill(fsrv->fsrv_pid, fsrv->fsrv_kill_signal); + waitpid(fsrv->fsrv_pid, NULL, 0); } @@ -1545,7 +1545,7 @@ afl_fsrv_run_target(afl_forkserver_t *fsrv, u32 timeout, s32 tmp_pid = fsrv->child_pid; if (tmp_pid > 0) { - kill(tmp_pid, fsrv->kill_signal); + kill(tmp_pid, fsrv->child_kill_signal); fsrv->child_pid = -1; } @@ -1605,7 +1605,7 @@ afl_fsrv_run_target(afl_forkserver_t *fsrv, u32 timeout, /* Did we timeout? */ if (unlikely(fsrv->last_run_timed_out)) { - fsrv->last_kill_signal = fsrv->kill_signal; + fsrv->last_kill_signal = fsrv->child_kill_signal; return FSRV_RUN_TMOUT; } @@ -1688,4 +1688,3 @@ void afl_fsrv_deinit(afl_forkserver_t *fsrv) { list_remove(&fsrv_list, fsrv); } - diff --git a/src/afl-fuzz-init.c b/src/afl-fuzz-init.c index e41d29fd..fded44ac 100644 --- a/src/afl-fuzz-init.c +++ b/src/afl-fuzz-init.c @@ -2963,4 +2963,3 @@ void save_cmdline(afl_state_t *afl, u32 argc, char **argv) { *buf = 0; } - diff --git a/src/afl-fuzz-state.c b/src/afl-fuzz-state.c index 5199f7e6..ae6cb6c7 100644 --- a/src/afl-fuzz-state.c +++ b/src/afl-fuzz-state.c @@ -23,6 +23,7 @@ */ +#include <signal.h> #include "afl-fuzz.h" #include "envs.h" @@ -484,10 +485,15 @@ void read_afl_environment(afl_state_t *afl, char **envp) { #endif } else if (!strncmp(env, "AFL_KILL_SIGNAL", + afl_environment_variable_len)) { + + afl->afl_env.afl_child_kill_signal = + (u8 *)get_afl_env(afl_environment_variables[i]); + } else if (!strncmp(env, "AFL_FORK_SERVER_KILL_SIGNAL", afl_environment_variable_len)) { - afl->afl_env.afl_kill_signal = + afl->afl_env.afl_fsrv_kill_signal = (u8 *)get_afl_env(afl_environment_variables[i]); } else if (!strncmp(env, "AFL_TARGET_ENV", @@ -653,9 +659,13 @@ void afl_states_stop(void) { }); LIST_FOREACH(&afl_states, afl_state_t, { - - if (el->fsrv.child_pid > 0) kill(el->fsrv.child_pid, el->fsrv.kill_signal); - if (el->fsrv.fsrv_pid > 0) kill(el->fsrv.fsrv_pid, el->fsrv.kill_signal); + /* NOTE: We need to make sure that the parent (the forkserver) reap the child (see below). */ + if (el->fsrv.child_pid > 0) kill(el->fsrv.child_pid, el->fsrv.child_kill_signal); + if (el->fsrv.fsrv_pid > 0) { + kill(el->fsrv.fsrv_pid, el->fsrv.fsrv_kill_signal); + /* Make sure the forkserver does not end up as zombie. */ + waitpid(el->fsrv.fsrv_pid, NULL, 0); + } }); @@ -672,4 +682,3 @@ void afl_states_request_skip(void) { LIST_FOREACH(&afl_states, afl_state_t, { el->skip_requested = 1; }); } - diff --git a/src/afl-fuzz.c b/src/afl-fuzz.c index d116822a..d8d804ae 100644 --- a/src/afl-fuzz.c +++ b/src/afl-fuzz.c @@ -25,6 +25,7 @@ #include "afl-fuzz.h" #include "cmplog.h" +#include "common.h" #include <limits.h> #include <stdlib.h> #ifndef USEMMAP @@ -261,6 +262,9 @@ static void usage(u8 *argv0, int more_help) { "AFL_INPUT_LEN_MIN/AFL_INPUT_LEN_MAX: like -g/-G set min/max fuzz length produced\n" "AFL_PIZZA_MODE: 1 - enforce pizza mode, 0 - disable for April 1st\n" "AFL_KILL_SIGNAL: Signal ID delivered to child processes on timeout, etc. (default: SIGKILL)\n" + "AFL_FORK_SERVER_KILL_SIGNAL: Signal delivered to fork server processes on termination\n" + " (default: SIGTERM). If this is not set and AFL_KILL_SIGNAL is set,\n" + " this will be set to the same value.\n" "AFL_MAP_SIZE: the shared memory size for that target. must be >= the size\n" " the target was compiled for\n" "AFL_MAX_DET_EXTRAS: if more entries are in the dictionary list than this value\n" @@ -1358,8 +1362,9 @@ int main(int argc, char **argv_orig, char **envp) { #endif - afl->fsrv.kill_signal = - parse_afl_kill_signal_env(afl->afl_env.afl_kill_signal, SIGKILL); + configure_afl_kill_signals(&afl->fsrv, + afl->afl_env.afl_child_kill_signal, + afl->afl_env.afl_fsrv_kill_signal); setup_signal_handlers(); check_asan_opts(afl); @@ -2683,4 +2688,3 @@ stop_fuzzing: } #endif /* !AFL_LIB */ - diff --git a/src/afl-showmap.c b/src/afl-showmap.c index 5e3fb67d..31091e8e 100644 --- a/src/afl-showmap.c +++ b/src/afl-showmap.c @@ -129,7 +129,7 @@ static void kill_child() { timed_out = 1; if (fsrv->child_pid > 0) { - kill(fsrv->child_pid, fsrv->kill_signal); + kill(fsrv->child_pid, fsrv->child_kill_signal); fsrv->child_pid = -1; } @@ -864,8 +864,11 @@ static void usage(u8 *argv0) { "AFL_DEBUG: enable extra developer output\n" "AFL_FORKSRV_INIT_TMOUT: time spent waiting for forkserver during " "startup (in milliseconds)\n" - "AFL_KILL_SIGNAL: Signal ID delivered to child processes on timeout, " - "etc. (default: SIGKILL)\n" + "AFL_KILL_SIGNAL: Signal ID delivered to child processes on timeout,\n" + " etc. (default: SIGKILL)\n" + "AFL_FORK_SERVER_KILL_SIGNAL: Signal delivered to fork server processes on termination\n" + " (default: SIGTERM). If this is not set and AFL_KILL_SIGNAL is set,\n" + " this will be set to the same value as AFL_KILL_SIGNAL.\n" "AFL_MAP_SIZE: the shared memory size for that target. must be >= the " "size the target was compiled for\n" "AFL_PRELOAD: LD_PRELOAD / DYLD_INSERT_LIBRARIES settings for target\n" @@ -1258,8 +1261,7 @@ int main(int argc, char **argv_orig, char **envp) { : 0); be_quiet = save_be_quiet; - fsrv->kill_signal = - parse_afl_kill_signal_env(getenv("AFL_KILL_SIGNAL"), SIGKILL); + configure_afl_kill_signals(fsrv, NULL, NULL); if (new_map_size) { @@ -1472,4 +1474,3 @@ int main(int argc, char **argv_orig, char **envp) { exit(ret); } - diff --git a/src/afl-tmin.c b/src/afl-tmin.c index 694c9c21..b346f65c 100644 --- a/src/afl-tmin.c +++ b/src/afl-tmin.c @@ -113,7 +113,7 @@ static void kill_child() { if (fsrv->child_pid > 0) { - kill(fsrv->child_pid, fsrv->kill_signal); + kill(fsrv->child_pid, fsrv->child_kill_signal); fsrv->child_pid = -1; } @@ -881,6 +881,9 @@ static void usage(u8 *argv0) { "AFL_CRASH_EXITCODE: optional child exit code to be interpreted as crash\n" "AFL_FORKSRV_INIT_TMOUT: time spent waiting for forkserver during startup (in milliseconds)\n" "AFL_KILL_SIGNAL: Signal ID delivered to child processes on timeout, etc. (default: SIGKILL)\n" + "AFL_FORK_SERVER_KILL_SIGNAL: Signal delivered to fork server processes on termination\n" + " (default: SIGTERM). If this is not set and AFL_KILL_SIGNAL is set,\n" + " this will be set to the same value as AFL_KILL_SIGNAL.\n" "AFL_MAP_SIZE: the shared memory size for that target. must be >= the size\n" " the target was compiled for\n" "AFL_PRELOAD: LD_PRELOAD / DYLD_INSERT_LIBRARIES settings for target\n" @@ -1195,8 +1198,8 @@ int main(int argc, char **argv_orig, char **envp) { } - fsrv->kill_signal = - parse_afl_kill_signal_env(getenv("AFL_KILL_SIGNAL"), SIGKILL); + configure_afl_kill_signals(fsrv, NULL, NULL); + if (getenv("AFL_CRASH_EXITCODE")) { @@ -1351,4 +1354,3 @@ int main(int argc, char **argv_orig, char **envp) { exit(0); } - |