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From:   Denis Efremov <efremov@linux.com>
To:     David Sterba <dsterba@suse.com>
Cc:     Denis Efremov <efremov@linux.com>,
        Josef Bacik <josef@toxicpanda.com>, Chris Mason <clm@fb.com>,
        linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org,
        Kees Cook <keescook@chromium.org>
Subject: [PATCH 2/2] btrfs: check allocation size in btrfs_ioctl_send()
Date:   Mon, 21 Sep 2020 20:03:36 +0300
Message-Id: <20200921170336.82643-2-efremov@linux.com>
In-Reply-To: <20200921170336.82643-1-efremov@linux.com>
References: <20200921170336.82643-1-efremov@linux.com>
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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