Consistently drop filter chain upon error.

4 files changed, 91 insertions, 49 deletions

diff --git a/include/mupdf/fitz/filter.h b/include/mupdf/fitz/filter.h
index 58dc3e21..2f73f02f 100644
--- a/include/mupdf/fitz/filter.h
+++ b/include/mupdf/fitz/filter.h
@@ -12,7 +12,7 @@ typedef struct fz_jbig2_globals_s fz_jbig2_globals;
 fz_stream *fz_open_copy(fz_context *ctx, fz_stream *chain);
 fz_stream *fz_open_null(fz_context *ctx, fz_stream *chain, int len, fz_off_t offset);
 fz_stream *fz_open_concat(fz_context *ctx, int max, int pad);
-void fz_concat_push(fz_context *ctx, fz_stream *concat, fz_stream *chain); /* Ownership of chain is passed in */
+void fz_concat_push_drop(fz_context *ctx, fz_stream *concat, fz_stream *chain); /* Ownership of chain is passed in */
 fz_stream *fz_open_arc4(fz_context *ctx, fz_stream *chain, unsigned char *key, unsigned keylen);
 fz_stream *fz_open_aesd(fz_context *ctx, fz_stream *chain, unsigned char *key, unsigned keylen);
 fz_stream *fz_open_a85d(fz_context *ctx, fz_stream *chain);
diff --git a/source/fitz/filter-basic.c b/source/fitz/filter-basic.c
index 5630c37b..959006f9 100644
--- a/source/fitz/filter-basic.c
+++ b/source/fitz/filter-basic.c
@@ -162,12 +162,15 @@ fz_open_concat(fz_context *ctx, int len, int pad)
 }
 
 void
-fz_concat_push(fz_context *ctx, fz_stream *concat, fz_stream *chain)
+fz_concat_push_drop(fz_context *ctx, fz_stream *concat, fz_stream *chain)
 {
 	struct concat_filter *state = (struct concat_filter *)concat->state;
 
 	if (state->count == state->max)
+	{
+		fz_drop_stream(ctx, chain);
 		fz_throw(ctx, FZ_ERROR_GENERIC, "Concat filter size exceeded");
+	}
 
 	state->chain[state->count++] = chain;
 }
diff --git a/source/pdf/pdf-crypt.c b/source/pdf/pdf-crypt.c
index e7f5f7a9..9f3b05e9 100644
--- a/source/pdf/pdf-crypt.c
+++ b/source/pdf/pdf-crypt.c
@@ -1023,12 +1023,26 @@ pdf_open_crypt(fz_context *ctx, fz_stream *chain, pdf_crypt *crypt, int num, int
 fz_stream *
 pdf_open_crypt_with_filter(fz_context *ctx, fz_stream *chain, pdf_crypt *crypt, pdf_obj *name, int num, int gen)
 {
-	if (!pdf_name_eq(ctx, name, PDF_NAME_Identity))
+	fz_var(chain);
+
+	fz_try(ctx)
+	{
+		if (!pdf_name_eq(ctx, name, PDF_NAME_Identity))
+		{
+			pdf_crypt_filter cf;
+			fz_stream *tmp;
+			pdf_parse_crypt_filter(ctx, &cf, crypt, name);
+			tmp = chain;
+			chain = NULL;
+			chain = pdf_open_crypt_imp(ctx, tmp, crypt, &cf, num, gen);
+		}
+	}
+	fz_catch(ctx)
 	{
-		pdf_crypt_filter cf;
-		pdf_parse_crypt_filter(ctx, &cf, crypt, name);
-		return pdf_open_crypt_imp(ctx, chain, crypt, &cf, num, gen);
+		fz_drop_stream(ctx, chain);
+		fz_rethrow(ctx);
 	}
+
 	return chain;
 }
 
diff --git a/source/pdf/pdf-stream.c b/source/pdf/pdf-stream.c
index 34757aa8..baf9f0a6 100644
--- a/source/pdf/pdf-stream.c
+++ b/source/pdf/pdf-stream.c
@@ -155,58 +155,82 @@ static fz_stream *
 build_filter(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_obj *f, pdf_obj *p, int num, int gen, fz_compression_params *params)
 {
 	fz_compression_params local_params;
+	fz_stream *tmp;
 
-	if (params == NULL)
-		params = &local_params;
-
-	build_compression_params(ctx, f, p, params);
-
-	/* If we were using params we were passed in, and we successfully
-	 * recognised the image type, we can use the existing filter and
-	 * shortstop here. */
-	if (params != &local_params && params->type != FZ_IMAGE_RAW)
-		return chain;
+	fz_var(chain);
 
-	if (params->type != FZ_IMAGE_RAW)
-		return fz_open_image_decomp_stream(ctx, chain, params, NULL);
+	fz_try(ctx)
+	{
+		if (params == NULL)
+			params = &local_params;
 
-	if (pdf_name_eq(ctx, f, PDF_NAME_ASCIIHexDecode) || pdf_name_eq(ctx, f, PDF_NAME_AHx))
-		return fz_open_ahxd(ctx, chain);
+		build_compression_params(ctx, f, p, params);
 
-	else if (pdf_name_eq(ctx, f, PDF_NAME_ASCII85Decode) || pdf_name_eq(ctx, f, PDF_NAME_A85))
-		return fz_open_a85d(ctx, chain);
+		/* If we were using params we were passed in, and we successfully
+		 * recognised the image type, we can use the existing filter and
+		 * shortstop here. */
+		if (params != &local_params && params->type != FZ_IMAGE_RAW)
+			break; /* nothing to do */
 
-	else if (pdf_name_eq(ctx, f, PDF_NAME_JBIG2Decode))
-	{
-		fz_jbig2_globals *globals = NULL;
-		pdf_obj *obj = pdf_dict_get(ctx, p, PDF_NAME_JBIG2Globals);
-		if (pdf_is_indirect(ctx, obj))
-			globals = pdf_load_jbig2_globals(ctx, doc, obj);
-		/* fz_open_jbig2d takes possession of globals */
-		return fz_open_jbig2d(ctx, chain, globals);
-	}
+		else if (params->type != FZ_IMAGE_RAW)
+		{
+			tmp = chain;
+			chain = NULL;
+			chain = fz_open_image_decomp_stream(ctx, tmp, params, NULL);
+		}
 
-	else if (pdf_name_eq(ctx, f, PDF_NAME_JPXDecode))
-		return chain; /* JPX decoding is special cased in the image loading code */
+		else if (pdf_name_eq(ctx, f, PDF_NAME_ASCIIHexDecode) || pdf_name_eq(ctx, f, PDF_NAME_AHx))
+		{
+			tmp = chain;
+			chain = NULL;
+			chain = fz_open_ahxd(ctx, tmp);
+		}
 
-	else if (pdf_name_eq(ctx, f, PDF_NAME_Crypt))
-	{
-		pdf_obj *name;
+		else if (pdf_name_eq(ctx, f, PDF_NAME_ASCII85Decode) || pdf_name_eq(ctx, f, PDF_NAME_A85))
+		{
+			tmp = chain;
+			chain = NULL;
+			chain = fz_open_a85d(ctx, tmp);
+		}
 
-		if (!doc->crypt)
+		else if (pdf_name_eq(ctx, f, PDF_NAME_JBIG2Decode))
 		{
-			fz_warn(ctx, "crypt filter in unencrypted document");
-			return chain;
+			fz_jbig2_globals *globals = NULL;
+			pdf_obj *obj = pdf_dict_get(ctx, p, PDF_NAME_JBIG2Globals);
+			if (pdf_is_indirect(ctx, obj))
+				globals = pdf_load_jbig2_globals(ctx, doc, obj);
+			tmp = chain;
+			chain = NULL;
+			chain = fz_open_jbig2d(ctx, tmp, globals);
 		}
 
-		name = pdf_dict_get(ctx, p, PDF_NAME_Name);
-		if (pdf_is_name(ctx, name))
-			return pdf_open_crypt_with_filter(ctx, chain, doc->crypt, name, num, gen);
+		else if (pdf_name_eq(ctx, f, PDF_NAME_JPXDecode))
+			break; /* JPX decoding is special cased in the image loading code */
 
-		return chain;
+		else if (pdf_name_eq(ctx, f, PDF_NAME_Crypt))
+		{
+			if (!doc->crypt)
+				fz_warn(ctx, "crypt filter in unencrypted document");
+			else
+			{
+				pdf_obj *name = pdf_dict_get(ctx, p, PDF_NAME_Name);
+				if (pdf_is_name(ctx, name))
+				{
+					tmp = chain;
+					chain = NULL;
+					chain = pdf_open_crypt_with_filter(ctx, tmp, doc->crypt, name, num, gen);
+				}
+			}
+		}
+		else
+			fz_warn(ctx, "unknown filter name (%s)", pdf_to_name(ctx, f));
+	}
+	fz_catch(ctx)
+	{
+		fz_drop_stream(ctx, chain);
+		fz_rethrow(ctx);
 	}
 
-	fz_warn(ctx, "unknown filter name (%s)", pdf_to_name(ctx, f));
 	return chain;
 }
 
@@ -635,14 +659,15 @@ pdf_open_object_array(fz_context *ctx, pdf_document *doc, pdf_obj *list)
 	{
 		pdf_obj *obj = pdf_array_get(ctx, list, i);
 		fz_try(ctx)
-		{
-			fz_concat_push(ctx, stm, pdf_open_stream(ctx, obj));
-		}
+			fz_concat_push_drop(ctx, stm, pdf_open_stream(ctx, obj));
 		fz_catch(ctx)
 		{
-			fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
+			if (fz_caught(ctx) == FZ_ERROR_TRYLATER)
+			{
+				fz_drop_stream(ctx, stm);
+				fz_rethrow(ctx);
+			}
 			fz_warn(ctx, "cannot load content stream part %d/%d", i + 1, n);
-			continue;
 		}
 	}