linux-kernel - [PATCH] erofs: fix double free of 'copied'

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Date:   Wed, 25 Aug 2021 20:07:57 +0800
From:   Gao Xiang <hsiangkao@...ux.alibaba.com>
To:     linux-erofs@...ts.ozlabs.org, Chao Yu <chao@...nel.org>,
        Liu Bo <bo.liu@...ux.alibaba.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Gao Xiang <hsiangkao@...ux.alibaba.com>,
        kernel test robot <lkp@...el.com>,
        Dan Carpenter <dan.carpenter@...cle.com>
Subject: [PATCH] erofs: fix double free of 'copied'

Dan reported a new smatch warning [1]
"fs/erofs/inode.c:210 erofs_read_inode() error: double free of 'copied'"

Due to new chunk-based format handling logic, the error path can be
called after kfree(copied).

Set "copied = NULL" after kfree(copied) to fix this.

[1] https://lore.kernel.org/r/202108251030.bELQozR7-lkp@intel.com
Fixes: c5aa903a59db ("erofs: support reading chunk-based uncompressed files")
Reported-by: kernel test robot <lkp@...el.com>
Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Gao Xiang <hsiangkao@...ux.alibaba.com>
---
 fs/erofs/inode.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 4408929bd6f5..31ac3a73b390 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -127,6 +127,7 @@ static struct page *erofs_read_inode(struct inode *inode,
 			/* fill chunked inode summary info */
 			vi->chunkformat = le16_to_cpu(die->i_u.c.format);
 		kfree(copied);
+		copied = NULL;
 		break;
 	case EROFS_INODE_LAYOUT_COMPACT:
 		vi->inode_isize = sizeof(struct erofs_inode_compact);
-- 
2.24.4