From: Chao Yu Date: Fri, 28 Feb 2020 10:08:46 +0000 (+0800) Subject: f2fs: fix to avoid use-after-free in f2fs_write_multi_pages() X-Git-Tag: v5.7-rc1~60^2~53 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=95978caa138948054e06d00bfc3432b518699f1b;p=linux-block.git f2fs: fix to avoid use-after-free in f2fs_write_multi_pages() In compress cluster, if physical block number is less than logic page number, race condition will cause use-after-free issue as described below: - f2fs_write_compressed_pages - fio.page = cic->rpages[0]; - f2fs_outplace_write_data - f2fs_compress_write_end_io - kfree(cic->rpages); - kfree(cic); - fio.page = cic->rpages[1]; f2fs_write_multi_pages+0xfd0/0x1a98 f2fs_write_data_pages+0x74c/0xb5c do_writepages+0x64/0x108 __writeback_single_inode+0xdc/0x4b8 writeback_sb_inodes+0x4d0/0xa68 __writeback_inodes_wb+0x88/0x178 wb_writeback+0x1f0/0x424 wb_workfn+0x2f4/0x574 process_one_work+0x210/0x48c worker_thread+0x2e8/0x44c kthread+0x110/0x120 ret_from_fork+0x10/0x18 Fixes: 4c8ff7095bef ("f2fs: support data compression") Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index 25bc6154c31c..411d1a5679ac 100644 --- a/fs/f2fs/compress.c +++ b/fs/f2fs/compress.c @@ -848,7 +848,7 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc, blkaddr = datablock_addr(dn.inode, dn.node_page, dn.ofs_in_node); - fio.page = cic->rpages[i]; + fio.page = cc->rpages[i]; fio.old_blkaddr = blkaddr; /* cluster header */