lib-mail: message-decoder - Fix using the new incremental base64-decoder API

Decoding multiple base64 blocks caused the decoder to produce garbage.
Broken by afa3db0a6f15e1b1038cb47f0632baa8f23d0f67

diff --git a/src/lib-mail/message-decoder.c b/src/lib-mail/message-decoder.c
index 83eff840e8f29a0b06bf7bdfef00aded38f37118..118060052a120dd9fdbc06a1e935ec94e4ccf771 100644 (file)
--- a/src/lib-mail/message-decoder.c
+++ b/src/lib-mail/message-decoder.c
@@ -30,6 +30,7 @@ struct message_decoder_context {
        size_t translation_size;
 
        struct qp_decoder *qp;
+       struct base64_decoder base64_decoder;
        buffer_t *encoding_buf;
 
        char *content_type, *content_charset;
@@ -54,6 +55,7 @@ message_decoder_init(normalizer_func_t *normalizer,
        ctx->buf = buffer_create_dynamic(default_pool, 8192);
        ctx->buf2 = buffer_create_dynamic(default_pool, 8192);
        ctx->encoding_buf = buffer_create_dynamic(default_pool, 128);
+       base64_decode_init(&ctx->base64_decoder, &base64_scheme, 0);
        return ctx;
 }
 
@@ -273,11 +275,9 @@ static bool message_decode_body(struct message_decoder_context *ctx,
                                struct message_block *input,
                                struct message_block *output)
 {
-       struct base64_decoder b64dec;
        const unsigned char *data = NULL;
        size_t pos = 0, size = 0;
        const char *error;
-       int ret;
 
        if (ctx->encoding_buf->used != 0)
                buffer_append(ctx->encoding_buf, input->data, input->size);
@@ -307,30 +307,21 @@ static bool message_decode_body(struct message_decoder_context *ctx,
                break;
        }
        case MESSAGE_CTE_BASE64:
+               i_assert(ctx->encoding_buf->used == 0);
                buffer_set_used_size(ctx->buf, 0);
-               base64_decode_init(&b64dec, &base64_scheme, 0);
-               if (ctx->encoding_buf->used != 0) {
-                       ret = base64_decode_more(&b64dec,
-                                                ctx->encoding_buf->data,
-                                                ctx->encoding_buf->used,
-                                                &pos, ctx->buf);
-               } else {
-                       ret = base64_decode_more(&b64dec,
-                                                input->data, input->size,
-                                                &pos, ctx->buf);
-               }
-               if (ret < 0 || base64_decode_finish(&b64dec) < 0) {
-                       /* corrupted base64 data, don't bother with
-                          the rest of it */
-                       return FALSE;
-               }
-               if (ret == 0) {
-                       /* end of base64 input */
-                       pos = input->size;
-                       buffer_set_used_size(ctx->encoding_buf, 0);
+               if (!base64_decode_is_finished(&ctx->base64_decoder)) {
+                       if (base64_decode_more(&ctx->base64_decoder,
+                                              input->data, input->size,
+                                              &pos, ctx->buf) <= 0) {
+                               /* ignore the rest of the input in this
+                                  MIME part */
+                               (void)base64_decode_finish(&ctx->base64_decoder);
+                       }
                }
                data = ctx->buf->data;
                size = ctx->buf->used;
+               /* eat away all input. base64-decoder buffers it internally. */
+               pos = input->size;
                break;
        }
 
@@ -402,6 +393,8 @@ void message_decoder_decode_reset(struct message_decoder_context *ctx)
 {
        const char *error;
 
+       base64_decode_reset(&ctx->base64_decoder);
+
        if (ctx->qp != NULL)
                (void)qp_decoder_finish(ctx->qp, &error);
        i_free_and_null(ctx->content_type);