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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Nikolay Borisov <nborisov@suse.com>,
        Anand Jain <anand.jain@oracle.com>, Qu Wenruo <wqu@suse.com>,
        David Sterba <dsterba@suse.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.2 020/143] btrfs: trim: Check the range passed into to prevent overflow
Date:   Wed,  4 Sep 2019 19:52:43 +0200
Message-Id: <20190904175314.862538430@linuxfoundation.org>
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[ Upstream commit 07301df7d2fc220d3de5f7ad804dcb941400cb00 ]

Normally the range->len is set to default value (U64_MAX), but when it's
not default value, we should check if the range overflows.

And if it overflows, return -EINVAL before doing anything.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/btrfs/extent-tree.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 5faf057f6f37f..b8f4720879021 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -11226,6 +11226,7 @@ int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
 	struct btrfs_device *device;
 	struct list_head *devices;
 	u64 group_trimmed;
+	u64 range_end = U64_MAX;
 	u64 start;
 	u64 end;
 	u64 trimmed = 0;
@@ -11235,16 +11236,23 @@ int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
 	int dev_ret = 0;
 	int ret = 0;
 
+	/*
+	 * Check range overflow if range->len is set.
+	 * The default range->len is U64_MAX.
+	 */
+	if (range->len != U64_MAX &&
+	    check_add_overflow(range->start, range->len, &range_end))
+		return -EINVAL;
+
 	cache = btrfs_lookup_first_block_group(fs_info, range->start);
 	for (; cache; cache = next_block_group(cache)) {
-		if (cache->key.objectid >= (range->start + range->len)) {
+		if (cache->key.objectid >= range_end) {
 			btrfs_put_block_group(cache);
 			break;
 		}
 
 		start = max(range->start, cache->key.objectid);
-		end = min(range->start + range->len,
-				cache->key.objectid + cache->key.offset);
+		end = min(range_end, cache->key.objectid + cache->key.offset);
 
 		if (end - start >= range->minlen) {
 			if (!block_group_cache_done(cache)) {
-- 
2.20.1