[PATCH 1/2] btrfs: use kvzalloc() to allocate clone_roots in btrfs_ioctl_send()

[PATCH 1/2] btrfs: use kvzalloc() to allocate clone_roots in btrfs_ioctl_send()

[Denis Efremov]

btrfs_ioctl_send() used open-coded kvzalloc implementation earlier.
The code was accidentally replaced with kzalloc() call [1]. Restore
the original code by using kvzalloc() to allocate sctx->clone_roots.

[1] https://patchwork.kernel.org/patch/9757891/#20529627

Cc: stable@vger.kernel.org
Fixes: 818e010bf9d0 ("btrfs: replace opencoded kvzalloc with the helper")
Signed-off-by: Denis Efremov <efremov@linux.com>
---
 fs/btrfs/send.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index d9813a5b075a..c874ddda6252 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -7181,7 +7181,7 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
 
 	alloc_size = sizeof(struct clone_root) * (arg->clone_sources_count + 1);
 
-	sctx->clone_roots = kzalloc(alloc_size, GFP_KERNEL);
+	sctx->clone_roots = kvzalloc(alloc_size, GFP_KERNEL);
 	if (!sctx->clone_roots) {
 		ret = -ENOMEM;
 		goto out;
-- 
2.26.2

[PATCH 2/2] btrfs: check allocation size in btrfs_ioctl_send()

[Denis Efremov]

Replace kvzalloc() call with kvcalloc() that checks
the size internally. Use array_size() helper to compute
the memory size for clone_sources_tmp.

Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Denis Efremov <efremov@linux.com>
---
 fs/btrfs/send.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index c874ddda6252..9e02aba30651 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -7087,7 +7087,7 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
 	u32 i;
 	u64 *clone_sources_tmp = NULL;
 	int clone_sources_to_rollback = 0;
-	unsigned alloc_size;
+	size_t alloc_size;
 	int sort_clone_roots = 0;
 
 	if (!capable(CAP_SYS_ADMIN))
@@ -7179,15 +7179,16 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
 	sctx->waiting_dir_moves = RB_ROOT;
 	sctx->orphan_dirs = RB_ROOT;
 
-	alloc_size = sizeof(struct clone_root) * (arg->clone_sources_count + 1);
-
-	sctx->clone_roots = kvzalloc(alloc_size, GFP_KERNEL);
+	sctx->clone_roots = kvcalloc(sizeof(*sctx->clone_roots),
+				     arg->clone_sources_count + 1,
+				     GFP_KERNEL);
 	if (!sctx->clone_roots) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
-	alloc_size = arg->clone_sources_count * sizeof(*arg->clone_sources);
+	alloc_size = array_size(sizeof(*arg->clone_sources),
+				arg->clone_sources_count);
 
 	if (arg->clone_sources_count) {
 		clone_sources_tmp = kvmalloc(alloc_size, GFP_KERNEL);
-- 
2.26.2

Re: [PATCH 2/2] btrfs: check allocation size in btrfs_ioctl_send()

[David Sterba]

On Mon, Sep 21, 2020 at 08:03:36PM +0300, Denis Efremov wrote:
> Replace kvzalloc() call with kvcalloc() that checks
> the size internally. Use array_size() helper to compute
> the memory size for clone_sources_tmp.
> 
> Cc: Kees Cook <keescook@chromium.org>
> Signed-off-by: Denis Efremov <efremov@linux.com>
> ---
>  fs/btrfs/send.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
> index c874ddda6252..9e02aba30651 100644
> --- a/fs/btrfs/send.c
> +++ b/fs/btrfs/send.c
> @@ -7087,7 +7087,7 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
>  	u32 i;
>  	u64 *clone_sources_tmp = NULL;
>  	int clone_sources_to_rollback = 0;
> -	unsigned alloc_size;
> +	size_t alloc_size;
>  	int sort_clone_roots = 0;
>  
>  	if (!capable(CAP_SYS_ADMIN))
> @@ -7179,15 +7179,16 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
>  	sctx->waiting_dir_moves = RB_ROOT;
>  	sctx->orphan_dirs = RB_ROOT;
>  
> -	alloc_size = sizeof(struct clone_root) * (arg->clone_sources_count + 1);
> -
> -	sctx->clone_roots = kvzalloc(alloc_size, GFP_KERNEL);
> +	sctx->clone_roots = kvcalloc(sizeof(*sctx->clone_roots),
> +				     arg->clone_sources_count + 1,
> +				     GFP_KERNEL);

There is an overflow check in btrfs_ioctl_send a few lines above, it
won't overflow at the allocation so this more like a cleanup than adding
a missing check, as the subject suggests.

Patches added to misc-next, thanks.

Re: [PATCH 1/2] btrfs: use kvzalloc() to allocate clone_roots in btrfs_ioctl_send()

[David Sterba]

On Mon, Sep 21, 2020 at 08:03:35PM +0300, Denis Efremov wrote:
> btrfs_ioctl_send() used open-coded kvzalloc implementation earlier.
> The code was accidentally replaced with kzalloc() call [1]. Restore
> the original code by using kvzalloc() to allocate sctx->clone_roots.
> 
> [1] https://patchwork.kernel.org/patch/9757891/#20529627
> 
> Cc: stable@vger.kernel.org
> Fixes: 818e010bf9d0 ("btrfs: replace opencoded kvzalloc with the helper")
> Signed-off-by: Denis Efremov <efremov@linux.com>

Thanks, the kvzalloc fixup got lost on the way.