2021-05-06 19:56:26

by Jaegeuk Kim

Subject: [PATCH] f2fs: return -EPERM given generic mask

In f2fs_fileattr_set(),

if (!fa->flags_valid)
mask &= FS_COMMON_FL;

In this case, we should not allow to set FS_COMPR_FL, instead of BUG_ON.

/* Flags shared betwen flags/xflags */
(FS_SYNC_FL | FS_IMMUTABLE_FL | FS_APPEND_FL | \
FS_NODUMP_FL | FS_NOATIME_FL | FS_DAX_FL | \
FS_PROJINHERIT_FL)

Fixes: 4c5b47997521 ("vfs: add fileattr ops")
Signed-off-by: Jaegeuk Kim <[email protected]>
---
fs/f2fs/file.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index e01ce802cf10..38015ef84893 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1817,7 +1817,9 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask)
struct f2fs_inode_info *fi = F2FS_I(inode);
u32 masked_flags = fi->i_flags & mask;

- f2fs_bug_on(F2FS_I_SB(inode), (iflags & ~mask));
+ /* mask can be shrunk by flags_valid selector */
+ if (iflags & ~mask)
+ return -EPERM;

/* Is it quota file? Do not allow user to mess with it */
if (IS_NOQUOTA(inode))
--
2.31.1.607.g51e8a6a459-goog

2021-05-07 06:48:49

by Eric Biggers

Subject: Re: [f2fs-dev] [PATCH] f2fs: return -EPERM given generic mask

On Thu, May 06, 2021 at 12:13:47PM -0700, Jaegeuk Kim wrote:
> In f2fs_fileattr_set(),
>
> if (!fa->flags_valid)
> mask &= FS_COMMON_FL;
>
> In this case, we should not allow to set FS_COMPR_FL, instead of BUG_ON.
>
> /* Flags shared betwen flags/xflags */
> (FS_SYNC_FL | FS_IMMUTABLE_FL | FS_APPEND_FL | \
> FS_NODUMP_FL | FS_NOATIME_FL | FS_DAX_FL | \
> FS_PROJINHERIT_FL)
>
> Fixes: 4c5b47997521 ("vfs: add fileattr ops")
> Signed-off-by: Jaegeuk Kim <[email protected]>
> ---
> fs/f2fs/file.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index e01ce802cf10..38015ef84893 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -1817,7 +1817,9 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask)
> struct f2fs_inode_info *fi = F2FS_I(inode);
> u32 masked_flags = fi->i_flags & mask;
>
> - f2fs_bug_on(F2FS_I_SB(inode), (iflags & ~mask));
> + /* mask can be shrunk by flags_valid selector */
> + if (iflags & ~mask)
> + return -EPERM;
>
> /* Is it quota file? Do not allow user to mess with it */
> if (IS_NOQUOTA(inode))
> --
> 2.31.1.607.g51e8a6a459-goog

This looks like the wrong fix. AFAICS, 'mask' is the set of inode flags that
the specific ioctl (FS_IOC_SETFLAGS or FS_IOC_FSSETXATTR) can potentially
modify, while 'iflags' is the new set of inode flags among the set that either
ioctl can potentially modify. So this change will stop FS_IOC_FSSETXATTR from
working on files that have already flags set which are only modifiable by
FS_IOC_SETFLAGS, e.g. the compression flag.

I think the correct fix would be to just do something like 'iflags &= mask'.

- Eric

2021-05-10 14:43:10

by Jaegeuk Kim

Subject: Re: [f2fs-dev] [PATCH] f2fs: return -EPERM given generic mask

On 05/06, Eric Biggers wrote:
> On Thu, May 06, 2021 at 12:13:47PM -0700, Jaegeuk Kim wrote:
> > In f2fs_fileattr_set(),
> >
> > if (!fa->flags_valid)
> > mask &= FS_COMMON_FL;
> >
> > In this case, we should not allow to set FS_COMPR_FL, instead of BUG_ON.
> >
> > /* Flags shared betwen flags/xflags */
> > (FS_SYNC_FL | FS_IMMUTABLE_FL | FS_APPEND_FL | \
> > FS_NODUMP_FL | FS_NOATIME_FL | FS_DAX_FL | \
> > FS_PROJINHERIT_FL)
> >
> > Fixes: 4c5b47997521 ("vfs: add fileattr ops")
> > Signed-off-by: Jaegeuk Kim <[email protected]>
> > ---
> > fs/f2fs/file.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index e01ce802cf10..38015ef84893 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -1817,7 +1817,9 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask)
> > struct f2fs_inode_info *fi = F2FS_I(inode);
> > u32 masked_flags = fi->i_flags & mask;
> >
> > - f2fs_bug_on(F2FS_I_SB(inode), (iflags & ~mask));
> > + /* mask can be shrunk by flags_valid selector */
> > + if (iflags & ~mask)
> > + return -EPERM;
> >
> > /* Is it quota file? Do not allow user to mess with it */
> > if (IS_NOQUOTA(inode))
> > --
> > 2.31.1.607.g51e8a6a459-goog
>
> This looks like the wrong fix. AFAICS, 'mask' is the set of inode flags that
> the specific ioctl (FS_IOC_SETFLAGS or FS_IOC_FSSETXATTR) can potentially
> modify, while 'iflags' is the new set of inode flags among the set that either
> ioctl can potentially modify. So this change will stop FS_IOC_FSSETXATTR from
> working on files that have already flags set which are only modifiable by
> FS_IOC_SETFLAGS, e.g. the compression flag.
>
> I think the correct fix would be to just do something like 'iflags &= mask'.

Thanks. Let me send v2.

>
> - Eric

2021-05-10 14:47:52

by Jaegeuk Kim

Subject: Re: [PATCH v2] f2fs: support iflag change given the mask

In f2fs_fileattr_set(),

if (!fa->flags_valid)
mask &= FS_COMMON_FL;

In this case, we can set supported flags by mask only instead of BUG_ON.

/* Flags shared betwen flags/xflags */
(FS_SYNC_FL | FS_IMMUTABLE_FL | FS_APPEND_FL | \
FS_NODUMP_FL | FS_NOATIME_FL | FS_DAX_FL | \
FS_PROJINHERIT_FL)

Fixes: 4c5b47997521 ("vfs: add fileattr ops")
Signed-off-by: Jaegeuk Kim <[email protected]>
---
fs/f2fs/file.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 44a4650aea7b..ceb575f99048 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1817,7 +1817,8 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask)
struct f2fs_inode_info *fi = F2FS_I(inode);
u32 masked_flags = fi->i_flags & mask;

- f2fs_bug_on(F2FS_I_SB(inode), (iflags & ~mask));
+ /* mask can be shrunk by flags_valid selector */
+ iflags &= mask;

/* Is it quota file? Do not allow user to mess with it */
if (IS_NOQUOTA(inode))
--
2.31.1.607.g51e8a6a459-goog

2021-05-10 22:32:18

by Eric Biggers

Subject: Re: [f2fs-dev] [PATCH v2] f2fs: support iflag change given the mask

On Mon, May 10, 2021 at 07:42:27AM -0700, Jaegeuk Kim wrote:
> In f2fs_fileattr_set(),
>
> if (!fa->flags_valid)
> mask &= FS_COMMON_FL;
>
> In this case, we can set supported flags by mask only instead of BUG_ON.
>
> /* Flags shared betwen flags/xflags */
> (FS_SYNC_FL | FS_IMMUTABLE_FL | FS_APPEND_FL | \
> FS_NODUMP_FL | FS_NOATIME_FL | FS_DAX_FL | \
> FS_PROJINHERIT_FL)
>
> Fixes: 4c5b47997521 ("vfs: add fileattr ops")

Shouldn't it be:

Fixes: 9b1bb01c8ae7 ("f2fs: convert to fileattr")

2021-05-11 00:23:30

by Jaegeuk Kim

Subject: Re: [f2fs-dev] [PATCH v2] f2fs: support iflag change given the mask

On 05/10, Eric Biggers wrote:
> On Mon, May 10, 2021 at 07:42:27AM -0700, Jaegeuk Kim wrote:
> > In f2fs_fileattr_set(),
> >
> > if (!fa->flags_valid)
> > mask &= FS_COMMON_FL;
> >
> > In this case, we can set supported flags by mask only instead of BUG_ON.
> >
> > /* Flags shared betwen flags/xflags */
> > (FS_SYNC_FL | FS_IMMUTABLE_FL | FS_APPEND_FL | \
> > FS_NODUMP_FL | FS_NOATIME_FL | FS_DAX_FL | \
> > FS_PROJINHERIT_FL)
> >
> > Fixes: 4c5b47997521 ("vfs: add fileattr ops")
>
> Shouldn't it be:
>
> Fixes: 9b1bb01c8ae7 ("f2fs: convert to fileattr")

Heh, thank you. I applied this change in the git. :)

2021-05-11 01:47:10

by Chao Yu

Subject: Re: [f2fs-dev] [PATCH v2] f2fs: support iflag change given the mask

On 2021/5/10 22:42, Jaegeuk Kim wrote:
> In f2fs_fileattr_set(),
>
> if (!fa->flags_valid)
> mask &= FS_COMMON_FL;
>
> In this case, we can set supported flags by mask only instead of BUG_ON.
>
> /* Flags shared betwen flags/xflags */
> (FS_SYNC_FL | FS_IMMUTABLE_FL | FS_APPEND_FL | \
> FS_NODUMP_FL | FS_NOATIME_FL | FS_DAX_FL | \
> FS_PROJINHERIT_FL)
>
> Fixes: 4c5b47997521 ("vfs: add fileattr ops")
> Signed-off-by: Jaegeuk Kim <[email protected]>

Except fixes line issue pointed out by Eric, other part looks good
to me.

Reviewed-by: Chao Yu <[email protected]>

Thanks,