Messages in this thread | | | Date | Thu, 6 May 2021 23:26:47 -0700 | From | Eric Biggers <> | Subject | Re: [f2fs-dev] [PATCH] f2fs: return -EPERM given generic mask |
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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 <jaegeuk@kernel.org> > --- > 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
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