[f2fs-dev] [PATCH] f2fs: do not allow to decompress files have FI_COMPRESS_RELEASED

[f2fs-dev] [PATCH] f2fs: do not allow to decompress files have FI_COMPRESS_RELEASED

[Jaewook Kim]

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. $ chattr +c ./file
2. $ dd if=/dev/zero of=./file bs=4096 count=2000 oflag=append conv=notrunc
3. $ sync
4. $ do_compress ./file      ; call F2FS_IOC_COMPRESS_FILE
5. $ get_compr_blocks ./file ; call F2FS_IOC_GET_COMPRESS_BLOCKS
6. $ do_compress ./file      ; call F2FS_IOC_COMPRESS_FILE again
7. $ get_compr_blocks ./file ; call F2FS_IOC_GET_COMPRESS_BLOCKS again

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>
---
 fs/f2fs/file.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 6b1b030830ca..a4713b7e12cb 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -3945,6 +3945,11 @@ static int f2fs_ioc_decompress_file(struct file *filp, unsigned long arg)
 		goto out;
 	}
 
+	if (is_inode_flag_set(inode, FI_COMPRESS_RELEASED)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
 	if (ret)
 		goto out;
@@ -4012,6 +4017,11 @@ static int f2fs_ioc_compress_file(struct file *filp, unsigned long arg)
 		goto out;
 	}
 
+	if (is_inode_flag_set(inode, FI_COMPRESS_RELEASED)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
 	if (ret)
 		goto out;
-- 
2.17.1



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Re: [f2fs-dev] [PATCH] f2fs: do not allow to decompress files have FI_COMPRESS_RELEASED

[Sungjong Seo]

> 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. $ chattr +c ./file
> 2. $ dd if=/dev/zero of=./file bs=4096 count=2000 oflag=append
> conv=notrunc 3. $ sync
> 4. $ do_compress ./file      ; call F2FS_IOC_COMPRESS_FILE
> 5. $ get_compr_blocks ./file ; call F2FS_IOC_GET_COMPRESS_BLOCKS

Oops! Do we need to call F2FS_IOC_RELEASE_COMPRESS_BLOCKS here?
Maybe, you need to revise reproduction process and to make v2 patch.

> 6. $ do_compress ./file      ; call F2FS_IOC_COMPRESS_FILE again
> 7. $ get_compr_blocks ./file ; call F2FS_IOC_GET_COMPRESS_BLOCKS again
> 
> 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>
> ---
>  fs/f2fs/file.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index
> 6b1b030830ca..a4713b7e12cb 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -3945,6 +3945,11 @@ static int f2fs_ioc_decompress_file(struct file
> *filp, unsigned long arg)
>  		goto out;
>  	}
> 
> +	if (is_inode_flag_set(inode, FI_COMPRESS_RELEASED)) {
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
>  	ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
>  	if (ret)
>  		goto out;
> @@ -4012,6 +4017,11 @@ static int f2fs_ioc_compress_file(struct file *filp,
> unsigned long arg)
>  		goto out;
>  	}
> 
> +	if (is_inode_flag_set(inode, FI_COMPRESS_RELEASED)) {
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
>  	ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
>  	if (ret)
>  		goto out;
> --
> 2.17.1




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[f2fs-dev] [PATCH v2] f2fs: do not allow to decompress files have FI_COMPRESS_RELEASED

[Jaewook Kim]

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>
---
v2:
 - Fix reproduction process and add test enviroment

 fs/f2fs/file.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 6b1b030830ca..a4713b7e12cb 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -3945,6 +3945,11 @@ static int f2fs_ioc_decompress_file(struct file *filp, unsigned long arg)
 		goto out;
 	}
 
+	if (is_inode_flag_set(inode, FI_COMPRESS_RELEASED)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
 	if (ret)
 		goto out;
@@ -4012,6 +4017,11 @@ static int f2fs_ioc_compress_file(struct file *filp, unsigned long arg)
 		goto out;
 	}
 
+	if (is_inode_flag_set(inode, FI_COMPRESS_RELEASED)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
 	if (ret)
 		goto out;
-- 
2.17.1



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Re: [f2fs-dev] [PATCH v2] f2fs: do not allow to decompress files have FI_COMPRESS_RELEASED

[Chao Yu]

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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