diff options
| -rw-r--r-- | docs/Changelog.md | 2 | ||||
| -rw-r--r-- | instrumentation/afl-compiler-rt.o.c | 23 | ||||
| m--------- | qemu_mode/qemuafl | 0 |
3 files changed, 13 insertions, 12 deletions
diff --git a/docs/Changelog.md b/docs/Changelog.md index 8222f942..9aea3638 100644 --- a/docs/Changelog.md +++ b/docs/Changelog.md @@ -9,7 +9,7 @@ Want to stay in the loop on major new features? Join our mailing list by sending a mail to <afl-users+subscribe@googlegroups.com>. ### Version ++3.12a (dev) - - ... + - fix cmplog rtn (rare crash and not being able to gather ptr data) ### Version ++3.11c (release) diff --git a/instrumentation/afl-compiler-rt.o.c b/instrumentation/afl-compiler-rt.o.c index 50b4e2c5..892118fb 100644 --- a/instrumentation/afl-compiler-rt.o.c +++ b/instrumentation/afl-compiler-rt.o.c @@ -1734,25 +1734,26 @@ static int area_is_valid(void *ptr, size_t len) { long r = syscall(SYS_write, __afl_dummy_fd[1], ptr, len); - if (unlikely(r <= 0 || r > len)) { // fail - maybe hitting asan boundary? + if (r <= 0 || r > len) return 0; - char *p = (char *)ptr; - long page_size = sysconf(_SC_PAGE_SIZE); - char *page = (char *)((uintptr_t)p & ~(page_size - 1)) + page_size; - if (page >= p + len) { return 0; } // no isnt, return fail - len = page - p - len; - r = syscall(SYS_write, __afl_dummy_fd[1], page, len); + // even if the write succeed this can be a false positive if we cross + // a page boundary. who knows why. - } + char *p = (char *)ptr; + long page_size = sysconf(_SC_PAGE_SIZE); + char *page = (char *)((uintptr_t)p & ~(page_size - 1)) + page_size; - // partial writes - we return what was written. - if (likely(r >= 0 && r <= len)) { + if (page > p + len) { + // no, not crossing a page boundary return (int)r; } else { - return 0; + // yes it crosses a boundary, hence we can only return the length of + // rest of the first page, we cannot detect if the next page is valid + // or not, neither by SYS_write nor msync() :-( + return (int)(page - p); } diff --git a/qemu_mode/qemuafl b/qemu_mode/qemuafl -Subproject 0fb212daab492411b3e323bc18a3074c1aecfd3 +Subproject d1ca56b84e78f821406eef28d836918edfc8d61 |