Messages in this thread | | | Date | Thu, 4 Aug 2022 21:32:54 +0800 | Subject | Re: [PATCH v2] f2fs: do not allow to decompress files have FI_COMPRESS_RELEASED | From | Chao Yu <> |
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On 2022/8/3 16:53, Jaewook Kim wrote: > If a file has FI_COMPRESS_RELEASED, all writes for it should not be > allowed. However, as of now, in case of compress_mode=user, writes > triggered by IOCTLs like F2FS_IOC_DE/COMPRESS_FILE are allowed unexpectly, > which could crash that file. > To fix it, let's do not allow F2FS_IOC_DE/COMPRESS_IOCTL if a file already > has FI_COMPRESS_RELEASED flag. > > This is the reproduction process: > 1. $ touch ./file > 2. $ chattr +c ./file > 3. $ dd if=/dev/random of=./file bs=4096 count=30 conv=notrunc > 4. $ dd if=/dev/zero of=./file bs=4096 count=34 seek=30 conv=notrunc > 5. $ sync > 6. $ do_compress ./file ; call F2FS_IOC_COMPRESS_FILE > 7. $ get_compr_blocks ./file ; call F2FS_IOC_GET_COMPRESS_BLOCKS > 8. $ release ./file ; call F2FS_IOC_RELEASE_COMPRESS_BLOCKS > 9. $ do_compress ./file ; call F2FS_IOC_COMPRESS_FILE again > 10. $ get_compr_blocks ./file ; call F2FS_IOC_GET_COMPRESS_BLOCKS again > > This reproduction process is tested in 128kb cluster size. > You can find compr_blocks has a negative value. > > Fixes: 5fdb322ff2c2b ("f2fs: add F2FS_IOC_DECOMPRESS_FILE and F2FS_IOC_COMPRESS_FILE") > > Signed-off-by: Junbeom Yeom <junbeom.yeom@samsung.com> > Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com> > Signed-off-by: Youngjin Gil <youngjin.gil@samsung.com> > Signed-off-by: Jaewook Kim <jw5454.kim@samsung.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Thanks,
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