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Issue google#110 - Fix afl-clang-fast -E and -shared regressions.
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choller committed Aug 5, 2020
1 parent fcf734a commit 6b8c514
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Showing 2 changed files with 30 additions and 1 deletion.
23 changes: 22 additions & 1 deletion llvm_mode/afl-clang-fast.c
Original file line number Diff line number Diff line change
Expand Up @@ -103,7 +103,8 @@ static void find_obj(u8* argv0) {

static void edit_params(u32 argc, char** argv) {

u8 fortify_set = 0, asan_set = 0, x_set = 0, bit_mode = 0;
u8 fortify_set = 0, asan_set = 0, x_set = 0, bit_mode = 0,
shared_linking = 0, preprocessor_only = 0;
u8 *name;

cc_params = ck_alloc((argc + 128) * sizeof(u8*));
Expand Down Expand Up @@ -158,6 +159,9 @@ static void edit_params(u32 argc, char** argv) {
if (!strcmp(cur, "-Wl,-z,defs") ||
!strcmp(cur, "-Wl,--no-undefined")) continue;

if (!strcmp(cur, "-E")) preprocessor_only = 1;
if (!strcmp(cur, "-shared")) shared_linking = 1;

cc_params[cc_par_cnt++] = cur;

}
Expand Down Expand Up @@ -277,6 +281,23 @@ static void edit_params(u32 argc, char** argv) {
cc_params[cc_par_cnt++] = "none";
}

if (preprocessor_only) {
/* In the preprocessor_only case (-E), we are not actually compiling at
all but requesting the compiler to output preprocessed sources only.
We must not add the runtime in this case because the compiler will
simply output its binary content back on stdout, breaking any build
systems that rely on a separate source preprocessing step. */
cc_params[cc_par_cnt] = NULL;
return;
}

if (!shared_linking) {
/* In order for AFL to work with shared libraries that are dynamically
loaded through dlopen(), we need to ensure that the main binary exports
the symbols used in the AFL runtime. */
cc_params[cc_par_cnt++] = alloc_printf("-Wl,--dynamic-list=%s/symfile.txt", obj_path);
}

#ifndef __ANDROID__
switch (bit_mode) {

Expand Down
8 changes: 8 additions & 0 deletions symfile.txt
Original file line number Diff line number Diff line change
@@ -0,0 +1,8 @@
{
"__afl_area_ptr";
"__afl_manual_init";
"__afl_persistent_loop";
"__afl_auto_init";
"__afl_area_initial";
"__afl_prev_loc";
};

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