2 files changed, 42 insertions, 6 deletions

diff --git a/lib/zlib_deflate/deflate.c b/lib/zlib_deflate/deflate.c
index 46a31e5f49c3..d63381e8e333 100644
--- a/lib/zlib_deflate/deflate.c
+++ b/lib/zlib_deflate/deflate.c
@@ -176,6 +176,7 @@ int zlib_deflateInit2(
     deflate_state *s;
     int noheader = 0;
     deflate_workspace *mem;
+    char *next;
 
     ush *overlay;
     /* We overlay pending_buf and d_buf+l_buf. This works since the average
@@ -199,6 +200,21 @@ int zlib_deflateInit2(
         strategy < 0 || strategy > Z_HUFFMAN_ONLY) {
         return Z_STREAM_ERROR;
     }
+
+    /*
+     * Direct the workspace's pointers to the chunks that were allocated
+     * along with the deflate_workspace struct.
+     */
+    next = (char *) mem;
+    next += sizeof(*mem);
+    mem->window_memory = (Byte *) next;
+    next += zlib_deflate_window_memsize(windowBits);
+    mem->prev_memory = (Pos *) next;
+    next += zlib_deflate_prev_memsize(windowBits);
+    mem->head_memory = (Pos *) next;
+    next += zlib_deflate_head_memsize(memLevel);
+    mem->overlay_memory = next;
+
     s = (deflate_state *) &(mem->deflate_memory);
     strm->state = (struct internal_state *)s;
     s->strm = strm;
@@ -1247,7 +1263,18 @@ static block_state deflate_slow(
     return flush == Z_FINISH ? finish_done : block_done;
 }
 
-int zlib_deflate_workspacesize(void)
+int zlib_deflate_workspacesize(int windowBits, int memLevel)
 {
-    return sizeof(deflate_workspace);
+    if (windowBits < 0) /* undocumented feature: suppress zlib header */
+        windowBits = -windowBits;
+
+    /* Since the return value is typically passed to vmalloc() unchecked... */
+    BUG_ON(memLevel < 1 || memLevel > MAX_MEM_LEVEL || windowBits < 9 ||
+                                                        windowBits > 15);
+
+    return sizeof(deflate_workspace)
+        + zlib_deflate_window_memsize(windowBits)
+        + zlib_deflate_prev_memsize(windowBits)
+        + zlib_deflate_head_memsize(memLevel)
+        + zlib_deflate_overlay_memsize(memLevel);
 }
diff --git a/lib/zlib_deflate/defutil.h b/lib/zlib_deflate/defutil.h
index 6b15a909ca3f..b640b6402e99 100644
--- a/lib/zlib_deflate/defutil.h
+++ b/lib/zlib_deflate/defutil.h
@@ -241,12 +241,21 @@ typedef struct deflate_state {
 typedef struct deflate_workspace {
     /* State memory for the deflator */
     deflate_state deflate_memory;
-    Byte window_memory[2 * (1 << MAX_WBITS)];
-    Pos prev_memory[1 << MAX_WBITS];
-    Pos head_memory[1 << (MAX_MEM_LEVEL + 7)];
-    char overlay_memory[(1 << (MAX_MEM_LEVEL + 6)) * (sizeof(ush)+2)];
+    Byte *window_memory;
+    Pos *prev_memory;
+    Pos *head_memory;
+    char *overlay_memory;
 } deflate_workspace;
 
+#define zlib_deflate_window_memsize(windowBits) \
+        (2 * (1 << (windowBits)) * sizeof(Byte))
+#define zlib_deflate_prev_memsize(windowBits) \
+        ((1 << (windowBits)) * sizeof(Pos))
+#define zlib_deflate_head_memsize(memLevel) \
+        ((1 << ((memLevel)+7)) * sizeof(Pos))
+#define zlib_deflate_overlay_memsize(memLevel) \
+        ((1 << ((memLevel)+6)) * (sizeof(ush)+2))
+
 /* Output a byte on the stream.
  * IN assertion: there is enough room in pending_buf.
  */