diff options
| author | Mark Johnston <markjdb@gmail.com> | 2020-08-07 12:46:48 -0400 |
|---|---|---|
| committer | Dmitry Vyukov <dvyukov@google.com> | 2020-08-08 11:09:48 +0200 |
| commit | 6ba54cf64ec7e5dcf8002c32b872685c905a9be8 (patch) | |
| tree | ebcdbe28de1d99e468a8d1cfff5ddcdfb8080b7f /executor/executor_bsd.h | |
| parent | ff51e5229e0ee846d2fd687cb0dbca13de758c66 (diff) | |
executor: use MAP_EXCL to map the data region on FreeBSD
We've had some problems where the default SYZ_DATA_OFFSET collides with
a mapping created by the C runtime. MAP_EXCL ensures that mmap() will
fail in this case, so such problems become a bit easier to diagnose.
Diffstat (limited to 'executor/executor_bsd.h')
| -rw-r--r-- | executor/executor_bsd.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/executor/executor_bsd.h b/executor/executor_bsd.h index d3ef16bce..65617d6b1 100644 --- a/executor/executor_bsd.h +++ b/executor/executor_bsd.h @@ -26,7 +26,13 @@ static void os_init(int argc, char** argv, void* data, size_t data_size) int prot = PROT_READ | PROT_WRITE | PROT_EXEC; #endif - if (mmap(data, data_size, prot, MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0) != data) + int flags = MAP_ANON | MAP_PRIVATE | MAP_FIXED; +#if GOOS_freebsd + // Fail closed if the chosen data offset conflicts with an existing mapping. + flags |= MAP_EXCL; +#endif + + if (mmap(data, data_size, prot, flags, -1, 0) != data) fail("mmap of data segment failed"); // Makes sure the file descriptor limit is sufficient to map control pipes. |