[Qemu-devel] [PATCH v4 0/6] vmdk: A few small fixes

[Qemu-devel] [PATCH v4 0/6] vmdk: A few small fixes

[Fam Zheng]

v4: Add Don's and Max's rev-by in 1, 3, 5, 6.
    2/6: Add VMFSSPARSE (Max)
    4/6: Don't set errno, and add a comment.

Fam Zheng (6):
  vmdk: Use g_random_int to generate CID
  vmdk: Fix comment to match code of extent lines
  vmdk: Clean up descriptor file reading
  vmdk: Check descriptor file length when reading it
  vmdk: Remove unnecessary initialization
  vmdk: Set errp on failures in vmdk_open_vmdk4

 block/vmdk.c | 29 ++++++++++++++++++++++-------
 1 file changed, 22 insertions(+), 7 deletions(-)

-- 
1.9.3

[Qemu-devel] [PATCH v4 1/6] vmdk: Use g_random_int to generate CID

[Fam Zheng]

This replaces two "time(NULL)" invocations with "g_random_int()".
According to VMDK spec, CID "is a random 32‐bit value updated the first
time the content of the virtual disk is modified after the virtual disk
is opened". Using "seconds since epoch" is just a "lame way" to generate
it, and not completely safe because of the low precision.

Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Don Koch <dkoch@verizon.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block/vmdk.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/block/vmdk.c b/block/vmdk.c
index 2cbfd3e..ebb4b70 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -28,6 +28,7 @@
 #include "qemu/module.h"
 #include "migration/migration.h"
 #include <zlib.h>
+#include <glib.h>
 
 #define VMDK3_MAGIC (('C' << 24) | ('O' << 16) | ('W' << 8) | 'D')
 #define VMDK4_MAGIC (('K' << 24) | ('D' << 16) | ('M' << 8) | 'V')
@@ -1538,7 +1539,7 @@ static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
         /* update CID on the first write every time the virtual disk is
          * opened */
         if (!s->cid_updated) {
-            ret = vmdk_write_cid(bs, time(NULL));
+            ret = vmdk_write_cid(bs, g_random_int());
             if (ret < 0) {
                 return ret;
             }
@@ -1922,7 +1923,7 @@ static int vmdk_create(const char *filename, QemuOpts *opts, Error **errp)
     }
     /* generate descriptor file */
     desc = g_strdup_printf(desc_template,
-                           (uint32_t)time(NULL),
+                           g_random_int(),
                            parent_cid,
                            fmt,
                            parent_desc_line,
-- 
1.9.3

[Qemu-devel] [PATCH v4 2/6] vmdk: Fix comment to match code of extent lines

[Fam Zheng]

commit 04d542c8b (vmdk: support vmfs files) added support of VMFS extent
type but the comment above the changed code is left out. Update the
comment so they are consistent.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block/vmdk.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/block/vmdk.c b/block/vmdk.c
index ebb4b70..4ee0aed 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -785,10 +785,12 @@ static int vmdk_parse_extents(const char *desc, BlockDriverState *bs,
     VmdkExtent *extent;
 
     while (*p) {
-        /* parse extent line:
+        /* parse extent line in one of below formats:
+         *
          * RW [size in sectors] FLAT "file-name.vmdk" OFFSET
-         * or
          * RW [size in sectors] SPARSE "file-name.vmdk"
+         * RW [size in sectors] VMFS "file-name.vmdk"
+         * RW [size in sectors] VMFSSPARSE "file-name.vmdk"
          */
         flat_offset = -1;
         ret = sscanf(p, "%10s %" SCNd64 " %10s \"%511[^\n\r\"]\" %" SCNd64,
-- 
1.9.3

[Qemu-devel] [PATCH v4 3/6] vmdk: Clean up descriptor file reading

[Fam Zheng]

Zeroing a buffer that will be filled right after is not necessary, and
allocating a power of two + 1 is naughty.

Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Don Koch <dkoch@verizon.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block/vmdk.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/block/vmdk.c b/block/vmdk.c
index 4ee0aed..5f43226 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -557,8 +557,8 @@ static char *vmdk_read_desc(BlockDriverState *file, uint64_t desc_offset,
         return NULL;
     }
 
-    size = MIN(size, 1 << 20);  /* avoid unbounded allocation */
-    buf = g_malloc0(size + 1);
+    size = MIN(size, (1 << 20) - 1);  /* avoid unbounded allocation */
+    buf = g_malloc(size + 1);
 
     ret = bdrv_pread(file, desc_offset, buf, size);
     if (ret < 0) {
@@ -566,6 +566,7 @@ static char *vmdk_read_desc(BlockDriverState *file, uint64_t desc_offset,
         g_free(buf);
         return NULL;
     }
+    buf[ret] = 0;
 
     return buf;
 }
-- 
1.9.3

[Qemu-devel] [PATCH v4 4/6] vmdk: Check descriptor file length when reading it

[Fam Zheng]

Since a too small file cannot be a valid VMDK image, and also since the
buffer's first 4 bytes will be unconditionally examined by
vmdk_open_sparse, let's error out the small file case to be clear.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block/vmdk.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/block/vmdk.c b/block/vmdk.c
index 5f43226..b703395 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -557,6 +557,14 @@ static char *vmdk_read_desc(BlockDriverState *file, uint64_t desc_offset,
         return NULL;
     }
 
+    if (size < 4) {
+        /* Both descriptor file and sparse image must be much larger than 4
+         * bytes, also callers of vmdk_read_desc want to compare the first 4
+         * bytes with VMDK4_MAGIC, let's error out if less is read. */
+        error_setg(errp, "File is too small, not a valid image");
+        return NULL;
+    }
+
     size = MIN(size, (1 << 20) - 1);  /* avoid unbounded allocation */
     buf = g_malloc(size + 1);
 
-- 
1.9.3

[Qemu-devel] [PATCH v4 5/6] vmdk: Remove unnecessary initialization

[Fam Zheng]

It will be assigned to the return value of vmdk_read_desc.

Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Don Koch <dkoch@verizon.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block/vmdk.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/vmdk.c b/block/vmdk.c
index b703395..da2d323 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -914,7 +914,7 @@ exit:
 static int vmdk_open(BlockDriverState *bs, QDict *options, int flags,
                      Error **errp)
 {
-    char *buf = NULL;
+    char *buf;
     int ret;
     BDRVVmdkState *s = bs->opaque;
     uint32_t magic;
-- 
1.9.3

[Qemu-devel] [PATCH v4 6/6] vmdk: Set errp on failures in vmdk_open_vmdk4

[Fam Zheng]

Reported-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Don Koch <dkoch@verizon.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block/vmdk.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/vmdk.c b/block/vmdk.c
index da2d323..65af414 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -645,6 +645,7 @@ static int vmdk_open_vmdk4(BlockDriverState *bs,
             bs->file->total_sectors * 512 - 1536,
             &footer, sizeof(footer));
         if (ret < 0) {
+            error_setg_errno(errp, -ret, "Failed to read footer");
             return ret;
         }
 
@@ -656,6 +657,7 @@ static int vmdk_open_vmdk4(BlockDriverState *bs,
             le32_to_cpu(footer.eos_marker.size) != 0  ||
             le32_to_cpu(footer.eos_marker.type) != MARKER_END_OF_STREAM)
         {
+            error_setg(errp, "Invalid footer");
             return -EINVAL;
         }
 
@@ -686,6 +688,7 @@ static int vmdk_open_vmdk4(BlockDriverState *bs,
     l1_entry_sectors = le32_to_cpu(header.num_gtes_per_gt)
                         * le64_to_cpu(header.granularity);
     if (l1_entry_sectors == 0) {
+        error_setg(errp, "L1 entry size is invalid");
         return -EINVAL;
     }
     l1_size = (le64_to_cpu(header.capacity) + l1_entry_sectors - 1)
-- 
1.9.3

Re: [Qemu-devel] [PATCH v4 2/6] vmdk: Fix comment to match code of extent lines

[Max Reitz]

On 2014-12-04 at 00:28, Fam Zheng wrote:
> commit 04d542c8b (vmdk: support vmfs files) added support of VMFS extent
> type but the comment above the changed code is left out. Update the
> comment so they are consistent.
>
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>   block/vmdk.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
>

Reviewed-by: Max Reitz <mreitz@redhat.com>

Re: [Qemu-devel] [PATCH v4 4/6] vmdk: Check descriptor file length when reading it

[Max Reitz]

On 2014-12-04 at 00:28, Fam Zheng wrote:
> Since a too small file cannot be a valid VMDK image, and also since the
> buffer's first 4 bytes will be unconditionally examined by
> vmdk_open_sparse, let's error out the small file case to be clear.
>
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>   block/vmdk.c | 8 ++++++++
>   1 file changed, 8 insertions(+)

Reviewed-by: Max Reitz <mreitz@redhat.com>

Re: [Qemu-devel] [PATCH v4 4/6] vmdk: Check descriptor file length when reading it

[Markus Armbruster]

Fam Zheng <famz@redhat.com> writes:

> Since a too small file cannot be a valid VMDK image, and also since the
> buffer's first 4 bytes will be unconditionally examined by
> vmdk_open_sparse, let's error out the small file case to be clear.
>
> Signed-off-by: Fam Zheng <famz@redhat.com>

Reviewed-by: Markus Armbruster <armbru@redhat.com>

Re: [Qemu-devel] [PATCH v4 2/6] vmdk: Fix comment to match code of extent lines

[Markus Armbruster]

Fam Zheng <famz@redhat.com> writes:

> commit 04d542c8b (vmdk: support vmfs files) added support of VMFS extent
> type but the comment above the changed code is left out. Update the
> comment so they are consistent.
>
> Signed-off-by: Fam Zheng <famz@redhat.com>

Reviewed-by: Markus Armbruster <armbru@redhat.com>

Re: [Qemu-devel] [PATCH v4 2/6] vmdk: Fix comment to match code of extent lines

[Don Koch]

On Thu, 4 Dec 2014 07:28:30 +0800
Fam Zheng <famz@redhat.com> wrote:

> commit 04d542c8b (vmdk: support vmfs files) added support of VMFS extent
> type but the comment above the changed code is left out. Update the
> comment so they are consistent.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---

Reviewed-by: Don Koch <dkoch@verizon.com>

>  block/vmdk.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/block/vmdk.c b/block/vmdk.c
> index ebb4b70..4ee0aed 100644
> --- a/block/vmdk.c
> +++ b/block/vmdk.c
> @@ -785,10 +785,12 @@ static int vmdk_parse_extents(const char *desc, BlockDriverState *bs,
>      VmdkExtent *extent;
>  
>      while (*p) {
> -        /* parse extent line:
> +        /* parse extent line in one of below formats:
> +         *
>           * RW [size in sectors] FLAT "file-name.vmdk" OFFSET
> -         * or
>           * RW [size in sectors] SPARSE "file-name.vmdk"
> +         * RW [size in sectors] VMFS "file-name.vmdk"
> +         * RW [size in sectors] VMFSSPARSE "file-name.vmdk"
>           */
>          flat_offset = -1;
>          ret = sscanf(p, "%10s %" SCNd64 " %10s \"%511[^\n\r\"]\" %" SCNd64,
> -- 
> 1.9.3
> 

Re: [Qemu-devel] [PATCH v4 4/6] vmdk: Check descriptor file length when reading it

[Don Koch]

On Thu, 4 Dec 2014 07:28:32 +0800
Fam Zheng <famz@redhat.com> wrote:

> Since a too small file cannot be a valid VMDK image, and also since the
> buffer's first 4 bytes will be unconditionally examined by
> vmdk_open_sparse, let's error out the small file case to be clear.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---

Reviewed-by: Don Koch <dkoch@verizon.com>

Re: [Qemu-devel] [PATCH v4 0/6] vmdk: A few small fixes

[Max Reitz]

On 2014-12-04 at 00:28, Fam Zheng wrote:
> v4: Add Don's and Max's rev-by in 1, 3, 5, 6.
>      2/6: Add VMFSSPARSE (Max)
>      4/6: Don't set errno, and add a comment.
>
> Fam Zheng (6):
>    vmdk: Use g_random_int to generate CID
>    vmdk: Fix comment to match code of extent lines
>    vmdk: Clean up descriptor file reading
>    vmdk: Check descriptor file length when reading it
>    vmdk: Remove unnecessary initialization
>    vmdk: Set errp on failures in vmdk_open_vmdk4
>
>   block/vmdk.c | 29 ++++++++++++++++++++++-------
>   1 file changed, 22 insertions(+), 7 deletions(-)

Thanks, applied to my block-next tree:

https://github.com/XanClic/qemu/commits/block-next