parallels: Sanity check for s->tracks (CVE-2014-0142)

[qemu.git] / block / parallels.c

diff --git a/block/parallels.c b/block/parallels.c
index efb6d4d6d413692d3984b3cc07b057fcfecba2a7..1a5bd350b3c53f54ebc4654efd5b754db62a5577 100644 (file)
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -24,8 +24,8 @@
  * THE SOFTWARE.
  */
 #include "qemu-common.h"
-#include "block_int.h"
-#include "module.h"
+#include "block/block_int.h"
+#include "qemu/module.h"
 
 /**************************************************************/
 
@@ -43,15 +43,15 @@ struct parallels_header {
     uint32_t catalog_entries;
     uint32_t nb_sectors;
     char padding[24];
-} __attribute__((packed));
+} QEMU_PACKED;
 
 typedef struct BDRVParallelsState {
-    int fd;
+    CoMutex lock;
 
     uint32_t *catalog_bitmap;
-    int catalog_size;
+    unsigned int catalog_size;
 
-    int tracks;
+    unsigned int tracks;
 } BDRVParallelsState;
 
 static int parallels_probe(const uint8_t *buf, int buf_size, const char *filename)
@@ -68,47 +68,59 @@ static int parallels_probe(const uint8_t *buf, int buf_size, const char *filenam
     return 0;
 }
 
-static int parallels_open(BlockDriverState *bs, const char *filename, int flags)
+static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
+                          Error **errp)
 {
     BDRVParallelsState *s = bs->opaque;
-    int fd, i;
+    int i;
     struct parallels_header ph;
-
-    fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
-    if (fd < 0) {
-        return -1;
-    }
+    int ret;
 
     bs->read_only = 1; // no write support yet
 
-    s->fd = fd;
-
-    if (pread(fd, &ph, sizeof(ph), 0) != sizeof(ph))
+    ret = bdrv_pread(bs->file, 0, &ph, sizeof(ph));
+    if (ret < 0) {
         goto fail;
+    }
 
     if (memcmp(ph.magic, HEADER_MAGIC, 16) ||
-       (le32_to_cpu(ph.version) != HEADER_VERSION)) {
+        (le32_to_cpu(ph.version) != HEADER_VERSION)) {
+        error_setg(errp, "Image not in Parallels format");
+        ret = -EINVAL;
         goto fail;
     }
 
     bs->total_sectors = le32_to_cpu(ph.nb_sectors);
 
     s->tracks = le32_to_cpu(ph.tracks);
+    if (s->tracks == 0) {
+        error_setg(errp, "Invalid image: Zero sectors per track");
+        ret = -EINVAL;
+        goto fail;
+    }
 
     s->catalog_size = le32_to_cpu(ph.catalog_entries);
-    s->catalog_bitmap = qemu_malloc(s->catalog_size * 4);
-    if (pread(s->fd, s->catalog_bitmap, s->catalog_size * 4, 64) !=
-       s->catalog_size * 4)
-       goto fail;
+    if (s->catalog_size > INT_MAX / 4) {
+        error_setg(errp, "Catalog too large");
+        ret = -EFBIG;
+        goto fail;
+    }
+    s->catalog_bitmap = g_malloc(s->catalog_size * 4);
+
+    ret = bdrv_pread(bs->file, 64, s->catalog_bitmap, s->catalog_size * 4);
+    if (ret < 0) {
+        goto fail;
+    }
+
     for (i = 0; i < s->catalog_size; i++)
        le32_to_cpus(&s->catalog_bitmap[i]);
 
+    qemu_co_mutex_init(&s->lock);
     return 0;
+
 fail:
-    if (s->catalog_bitmap)
-       qemu_free(s->catalog_bitmap);
-    close(fd);
-    return -1;
+    g_free(s->catalog_bitmap);
+    return ret;
 }
 
 static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
@@ -128,12 +140,10 @@ static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
 static int parallels_read(BlockDriverState *bs, int64_t sector_num,
                     uint8_t *buf, int nb_sectors)
 {
-    BDRVParallelsState *s = bs->opaque;
-
     while (nb_sectors > 0) {
         int64_t position = seek_to_sector(bs, sector_num);
         if (position >= 0) {
-            if (pread(s->fd, buf, 512, position) != 512)
+            if (bdrv_pread(bs->file, position, buf, 512) != 512)
                 return -1;
         } else {
             memset(buf, 0, 512);
@@ -145,19 +155,29 @@ static int parallels_read(BlockDriverState *bs, int64_t sector_num,
     return 0;
 }
 
+static coroutine_fn int parallels_co_read(BlockDriverState *bs, int64_t sector_num,
+                                          uint8_t *buf, int nb_sectors)
+{
+    int ret;
+    BDRVParallelsState *s = bs->opaque;
+    qemu_co_mutex_lock(&s->lock);
+    ret = parallels_read(bs, sector_num, buf, nb_sectors);
+    qemu_co_mutex_unlock(&s->lock);
+    return ret;
+}
+
 static void parallels_close(BlockDriverState *bs)
 {
     BDRVParallelsState *s = bs->opaque;
-    qemu_free(s->catalog_bitmap);
-    close(s->fd);
+    g_free(s->catalog_bitmap);
 }
 
 static BlockDriver bdrv_parallels = {
     .format_name       = "parallels",
     .instance_size     = sizeof(BDRVParallelsState),
     .bdrv_probe                = parallels_probe,
-    .bdrv_file_open    = parallels_open,
-    .bdrv_read         = parallels_read,
+    .bdrv_open         = parallels_open,
+    .bdrv_read          = parallels_co_read,
     .bdrv_close                = parallels_close,
 };