lib: istream-base64-encoder - Fix handling of error, EOF and stream buffer overflow...

diff --git a/src/lib/istream-base64-encoder.c b/src/lib/istream-base64-encoder.c
index 6cda4d6aa651e582474b5a63143a008bd11152cd..fff2fceb27835ba7cb9046ac5e6080cc4defd3f9 100644 (file)
--- a/src/lib/istream-base64-encoder.c
+++ b/src/lib/istream-base64-encoder.c
@@ -18,11 +18,9 @@ static int i_stream_read_parent(struct istream_private *stream)
        ssize_t ret;
 
        size = i_stream_get_data_size(stream->parent);
-       if (size >= 3)
+       if (size > 0)
                return 1;
 
-       /* we have less than one base64 block.
-          see if there is more data available. */
        ret = i_stream_read_memarea(stream->parent);
        if (ret <= 0) {
                stream->istream.stream_errno = stream->parent->stream_errno;
@@ -43,7 +41,7 @@ i_stream_base64_try_encode(struct base64_encoder_istream *bstream)
        buffer_t buf;
 
        data = i_stream_get_data(stream->parent, &size);
-       if (size == 0 || (size < 3 && !stream->parent->eof))
+       if (size == 0)
                return 0;
 
        out_size = base64_encode_get_size(b64enc, size);
@@ -82,6 +80,8 @@ i_stream_base64_finish_encode(struct base64_encoder_istream *bstream)
                                buffer_avail);
        if (base64_encode_finish(b64enc, &buf))
                stream->istream.eof = TRUE;
+       i_assert(buf.used > 0);
+
        stream->pos += buf.used;
        return 1;
 }
@@ -104,6 +104,8 @@ static ssize_t i_stream_base64_encoder_read(struct istream_private *stream)
                if (ret == 0)
                        return 0;
                if (ret < 0) {
+                       if (stream->istream.stream_errno != 0)
+                               return -1;
                        if (i_stream_get_data_size(stream->parent) == 0)
                                break;
                        /* add the final partial block */
@@ -115,18 +117,22 @@ static ssize_t i_stream_base64_encoder_read(struct istream_private *stream)
                post_count = stream->pos - stream->skip;
        } while (ret == 0 && pre_count == post_count);
 
-       if (ret < 0) {
-               if (ret == -2)
-                       return ret;
+       if (ret == -2) {
+               if (pre_count == post_count)
+                       return -2;
+       } else if (ret < 0) {
                if (i_stream_get_data_size(stream->parent) == 0) {
+                       i_assert(post_count == pre_count);
                        pre_count = stream->pos - stream->skip;
                        ret = i_stream_base64_finish_encode(bstream);
                        post_count = stream->pos - stream->skip;
                        if (ret <= 0)
                                return ret;
                }
-               if (pre_count == post_count)
+               if (pre_count == post_count) {
+                       stream->istream.eof = TRUE;
                        return -1;
+               }
        }
 
        i_assert(post_count > pre_count);