stephan.yichao.zhao created this revision.
stephan.yichao.zhao added a reviewer: morehouse.
stephan.yichao.zhao requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D105378
Files:
clang/docs/DataFlowSanitizer.rst
Index: clang/docs/DataFlowSanitizer.rst
===================================================================
--- clang/docs/DataFlowSanitizer.rst
+++ clang/docs/DataFlowSanitizer.rst
@@ -191,6 +191,44 @@
return 0;
}
+Origin Tracking
+===============
+
+DataFlowSanitizer can track origins of labeled values. This feature is enabled
by
+``-mllvm -dfsan-track-origins=1``. For example,
+
+.. code-block:: console
+
+ % cat test.cc
+ #include <sanitizer/dfsan_interface.h>
+ #include <stdio.h>
+
+ int main(int argc, char** argv) {
+ int i = 0;
+ dfsan_set_label(i_label, &i, sizeof(i));
+ int j = i + 1;
+ dfsan_print_origin_trace(&j, "A flow from i to j");
+ return 0;
+ }
+
+ % clang -fsanitize=dataflow -mllvm -dfsan-track-origins=1
-fno-omit-frame-pointer -g -O2 test.cc
+ % ./a.out
+ Taint value 0x1 (at 0x7ffd42bf415c) origin tracking (A flow from i to j)
+ Origin value: 0x13900001, Taint value was stored to memory at
+ #0 0x55676db85a62 in main test.cc:7:7
+ #1 0x7f0083611bbc in __libc_start_main libc-start.c:285
+
+ Origin value: 0x9e00001, Taint value was created at
+ #0 0x55676db85a08 in main test.cc:6:3
+ #1 0x7f0083611bbc in __libc_start_main libc-start.c:285
+
+By ``-mllvm -dfsan-track-origins=1`` DataFlowSanitizer collects only
+intermediate stores a labeled value went through. Origin tracking slows down
+program execution by a factor of 2x on top of the usual DataFlowSanitizer
+slowdown and increases memory overhead by 1x. By ``-mllvm
-dfsan-track-origins=2``
+DataFlowSanitizer also collects intermediate loads a labeled value went
through.
+This mode slows down program execution by a factor of 4x.
+
Current status
==============
Index: clang/docs/DataFlowSanitizer.rst
===================================================================
--- clang/docs/DataFlowSanitizer.rst
+++ clang/docs/DataFlowSanitizer.rst
@@ -191,6 +191,44 @@
return 0;
}
+Origin Tracking
+===============
+
+DataFlowSanitizer can track origins of labeled values. This feature is enabled by
+``-mllvm -dfsan-track-origins=1``. For example,
+
+.. code-block:: console
+
+ % cat test.cc
+ #include <sanitizer/dfsan_interface.h>
+ #include <stdio.h>
+
+ int main(int argc, char** argv) {
+ int i = 0;
+ dfsan_set_label(i_label, &i, sizeof(i));
+ int j = i + 1;
+ dfsan_print_origin_trace(&j, "A flow from i to j");
+ return 0;
+ }
+
+ % clang -fsanitize=dataflow -mllvm -dfsan-track-origins=1 -fno-omit-frame-pointer -g -O2 test.cc
+ % ./a.out
+ Taint value 0x1 (at 0x7ffd42bf415c) origin tracking (A flow from i to j)
+ Origin value: 0x13900001, Taint value was stored to memory at
+ #0 0x55676db85a62 in main test.cc:7:7
+ #1 0x7f0083611bbc in __libc_start_main libc-start.c:285
+
+ Origin value: 0x9e00001, Taint value was created at
+ #0 0x55676db85a08 in main test.cc:6:3
+ #1 0x7f0083611bbc in __libc_start_main libc-start.c:285
+
+By ``-mllvm -dfsan-track-origins=1`` DataFlowSanitizer collects only
+intermediate stores a labeled value went through. Origin tracking slows down
+program execution by a factor of 2x on top of the usual DataFlowSanitizer
+slowdown and increases memory overhead by 1x. By ``-mllvm -dfsan-track-origins=2``
+DataFlowSanitizer also collects intermediate loads a labeled value went through.
+This mode slows down program execution by a factor of 4x.
+
Current status
==============
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