[pve-devel] [PATCH qemu] fix #4726: avoid superfluous check in vma code

[pve-devel] [PATCH qemu] fix #4726: avoid superfluous check in vma code

[Fiona Ebner]

The 'status' pointer is dereferenced after the NULL check. Since all
callers pass in the address of a struct on the stack, the pointer can
never be NULL. Remove the superfluous check and add an assert instead.

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
 ...VE-Backup-add-vma-backup-format-code.patch | 23 +++++++++----------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/debian/patches/pve/0027-PVE-Backup-add-vma-backup-format-code.patch b/debian/patches/pve/0027-PVE-Backup-add-vma-backup-format-code.patch
index ee40ab8..d6d7767 100644
--- a/debian/patches/pve/0027-PVE-Backup-add-vma-backup-format-code.patch
+++ b/debian/patches/pve/0027-PVE-Backup-add-vma-backup-format-code.patch
@@ -16,10 +16,10 @@ Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
  block/meson.build |   2 +
  meson.build       |   5 +
  vma-reader.c      | 870 ++++++++++++++++++++++++++++++++++++++++++++
- vma-writer.c      | 818 +++++++++++++++++++++++++++++++++++++++++
+ vma-writer.c      | 817 +++++++++++++++++++++++++++++++++++++++++
  vma.c             | 901 ++++++++++++++++++++++++++++++++++++++++++++++
  vma.h             | 150 ++++++++
- 6 files changed, 2746 insertions(+)
+ 6 files changed, 2745 insertions(+)
  create mode 100644 vma-reader.c
  create mode 100644 vma-writer.c
  create mode 100644 vma.c
@@ -939,10 +939,10 @@ index 0000000000..d0b6721812
 +
 diff --git a/vma-writer.c b/vma-writer.c
 new file mode 100644
-index 0000000000..126b296647
+index 0000000000..a466652a5d
 --- /dev/null
 +++ b/vma-writer.c
-@@ -0,0 +1,818 @@
+@@ -0,0 +1,817 @@
 +/*
 + * VMA: Virtual Machine Archive
 + *
@@ -1517,17 +1517,16 @@ index 0000000000..126b296647
 +    int i;
 +
 +    g_assert(vmaw != NULL);
++    g_assert(status != NULL);
 +
-+    if (status) {
-+        status->status = vmaw->status;
-+        g_strlcpy(status->errmsg, vmaw->errmsg, sizeof(status->errmsg));
-+        for (i = 0; i <= 255; i++) {
-+            status->stream_info[i] = vmaw->stream_info[i];
-+        }
-+
-+        uuid_unparse_lower(vmaw->uuid, status->uuid_str);
++    status->status = vmaw->status;
++    g_strlcpy(status->errmsg, vmaw->errmsg, sizeof(status->errmsg));
++    for (i = 0; i <= 255; i++) {
++        status->stream_info[i] = vmaw->stream_info[i];
 +    }
 +
++    uuid_unparse_lower(vmaw->uuid, status->uuid_str);
++
 +    status->closed = vmaw->closed;
 +
 +    return vmaw->status;
-- 
2.39.2



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Re: [pve-devel] [PATCH qemu] fix #4726: avoid superfluous check in vma code

[Fabian Grünbichler]

On June 14, 2024 12:50 pm, Fiona Ebner wrote:
> The 'status' pointer is dereferenced after the NULL check. Since all
> callers pass in the address of a struct on the stack, the pointer can
> never be NULL. Remove the superfluous check and add an assert instead.
> 
> Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>

Reviewed-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>

> ---
>  ...VE-Backup-add-vma-backup-format-code.patch | 23 +++++++++----------
>  1 file changed, 11 insertions(+), 12 deletions(-)
> 
> diff --git a/debian/patches/pve/0027-PVE-Backup-add-vma-backup-format-code.patch b/debian/patches/pve/0027-PVE-Backup-add-vma-backup-format-code.patch
> index ee40ab8..d6d7767 100644
> --- a/debian/patches/pve/0027-PVE-Backup-add-vma-backup-format-code.patch
> +++ b/debian/patches/pve/0027-PVE-Backup-add-vma-backup-format-code.patch
> @@ -16,10 +16,10 @@ Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
>   block/meson.build |   2 +
>   meson.build       |   5 +
>   vma-reader.c      | 870 ++++++++++++++++++++++++++++++++++++++++++++
> - vma-writer.c      | 818 +++++++++++++++++++++++++++++++++++++++++
> + vma-writer.c      | 817 +++++++++++++++++++++++++++++++++++++++++
>   vma.c             | 901 ++++++++++++++++++++++++++++++++++++++++++++++
>   vma.h             | 150 ++++++++
> - 6 files changed, 2746 insertions(+)
> + 6 files changed, 2745 insertions(+)
>   create mode 100644 vma-reader.c
>   create mode 100644 vma-writer.c
>   create mode 100644 vma.c
> @@ -939,10 +939,10 @@ index 0000000000..d0b6721812
>  +
>  diff --git a/vma-writer.c b/vma-writer.c
>  new file mode 100644
> -index 0000000000..126b296647
> +index 0000000000..a466652a5d
>  --- /dev/null
>  +++ b/vma-writer.c
> -@@ -0,0 +1,818 @@
> +@@ -0,0 +1,817 @@
>  +/*
>  + * VMA: Virtual Machine Archive
>  + *
> @@ -1517,17 +1517,16 @@ index 0000000000..126b296647
>  +    int i;
>  +
>  +    g_assert(vmaw != NULL);
> ++    g_assert(status != NULL);
>  +
> -+    if (status) {
> -+        status->status = vmaw->status;
> -+        g_strlcpy(status->errmsg, vmaw->errmsg, sizeof(status->errmsg));
> -+        for (i = 0; i <= 255; i++) {
> -+            status->stream_info[i] = vmaw->stream_info[i];
> -+        }
> -+
> -+        uuid_unparse_lower(vmaw->uuid, status->uuid_str);
> ++    status->status = vmaw->status;
> ++    g_strlcpy(status->errmsg, vmaw->errmsg, sizeof(status->errmsg));
> ++    for (i = 0; i <= 255; i++) {
> ++        status->stream_info[i] = vmaw->stream_info[i];
>  +    }
>  +
> ++    uuid_unparse_lower(vmaw->uuid, status->uuid_str);
> ++
>  +    status->closed = vmaw->closed;
>  +
>  +    return vmaw->status;
> -- 
> 2.39.2
> 
> 
> 
> _______________________________________________
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> pve-devel@lists.proxmox.com
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> 
> 
> 


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