3 files changed, 20 insertions, 12 deletions
diff --git a/src/liblzma/common/alone_decoder.c b/src/liblzma/common/alone_decoder.c
index fa7fb839..039b4285 100644
--- a/src/liblzma/common/alone_decoder.c
+++ b/src/liblzma/common/alone_decoder.c
@@ -173,12 +173,15 @@ static lzma_ret
 alone_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
 		uint64_t *old_memlimit, uint64_t new_memlimit)
 {
-	if (new_memlimit != 0 && new_memlimit < coder->memusage)
-		return LZMA_MEMLIMIT_ERROR;
-
 	*memusage = coder->memusage;
 	*old_memlimit = coder->memlimit;
-	coder->memlimit = new_memlimit;
+
+	if (new_memlimit != 0) {
+		if (new_memlimit < coder->memusage)
+			return LZMA_MEMLIMIT_ERROR;
+
+		coder->memlimit = new_memlimit;
+	}
 
 	return LZMA_OK;
 }
diff --git a/src/liblzma/common/index_decoder.c b/src/liblzma/common/index_decoder.c
index a3ea791f..86a22971 100644
--- a/src/liblzma/common/index_decoder.c
+++ b/src/liblzma/common/index_decoder.c
@@ -219,12 +219,14 @@ index_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
 		uint64_t *old_memlimit, uint64_t new_memlimit)
 {
 	*memusage = lzma_index_memusage(1, coder->count);
+	*old_memlimit = coder->memlimit;
 
-	if (new_memlimit != 0 && new_memlimit < *memusage)
-		return LZMA_MEMLIMIT_ERROR;
+	if (new_memlimit != 0) {
+		if (new_memlimit < *memusage)
+			return LZMA_MEMLIMIT_ERROR;
 
-	*old_memlimit = coder->memlimit;
-	coder->memlimit = new_memlimit;
+		coder->memlimit = new_memlimit;
+	}
 
 	return LZMA_OK;
 }
diff --git a/src/liblzma/common/stream_decoder.c b/src/liblzma/common/stream_decoder.c
index 680fc53e..60cc8247 100644
--- a/src/liblzma/common/stream_decoder.c
+++ b/src/liblzma/common/stream_decoder.c
@@ -383,12 +383,15 @@ static lzma_ret
 stream_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
 		uint64_t *old_memlimit, uint64_t new_memlimit)
 {
-	if (new_memlimit != 0 && new_memlimit < coder->memusage)
-		return LZMA_MEMLIMIT_ERROR;
-
 	*memusage = coder->memusage;
 	*old_memlimit = coder->memlimit;
-	coder->memlimit = new_memlimit;
+
+	if (new_memlimit != 0) {
+		if (new_memlimit < coder->memusage)
+			return LZMA_MEMLIMIT_ERROR;
+
+		coder->memlimit = new_memlimit;
+	}
 
 	return LZMA_OK;
 }