2020-09-21 17:07:11

by Denis Efremov

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

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: [email protected]
Fixes: 818e010bf9d0 ("btrfs: replace opencoded kvzalloc with the helper")
Signed-off-by: Denis Efremov <[email protected]>
---
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

2020-09-21 17:07:16

by Denis Efremov

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

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 <[email protected]>
Signed-off-by: Denis Efremov <[email protected]>
---
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

2020-09-21 18:48:50

by David Sterba

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

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: [email protected]
> Fixes: 818e010bf9d0 ("btrfs: replace opencoded kvzalloc with the helper")
> Signed-off-by: Denis Efremov <[email protected]>

Thanks, the kvzalloc fixup got lost on the way.

2020-09-21 18:52:28

by David Sterba

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

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 <[email protected]>
> Signed-off-by: Denis Efremov <[email protected]>
> ---
> 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.