fix twos complement overflow bug in mem streams boundary check

[musl] / src / stdio / open_wmemstream.c

diff --git a/src/stdio/open_wmemstream.c b/src/stdio/open_wmemstream.c
index 3bc0f25..41b92d2 100644 (file)
--- a/src/stdio/open_wmemstream.c
+++ b/src/stdio/open_wmemstream.c
@@ -29,7 +29,7 @@ static off_t wms_seek(FILE *f, off_t off, int whence)
                errno = EINVAL;
                return -1;
        }
-       if (-off > base || off > SSIZE_MAX/4-base) goto fail;
+       if (off < -base || off > SSIZE_MAX/4-base) goto fail;
        memset(&c->mbs, 0, sizeof c->mbs);
        return c->pos = base+off;
 }