| Submitter | Eric W. Biederman |
|---|---|
| Date | 2009-11-03 11:57:02 |
| Message ID | <1257249429-12384-6-git-send-email-ebiederm@xmission.com> |
| Download | mbox | patch |
| Permalink | /patch/57282/ |
| State | New |
| Headers | show |
Comments
Quoting Eric W. Biederman (ebiederm@xmission.com): > From: Eric W. Biederman <ebiederm@xmission.com> > > Cleanly separate the work that is specific to setting the > attributes of a sysfs_dirent from what is needed to update > the attributes of a vfs inode. > > Additionally grab the sysfs_mutex to keep any nasties from > surprising us when updating the sysfs_dirent. > > Acked-by: Tejun Heo <tj@kernel.org> > Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com> > --- > fs/sysfs/inode.c | 52 ++++++++++++++++++++++++++++++++-------------------- > fs/sysfs/sysfs.h | 1 + > 2 files changed, 33 insertions(+), 20 deletions(-) > > diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c > index fed7a74..fccfb55 100644 > --- a/fs/sysfs/inode.c > +++ b/fs/sysfs/inode.c > @@ -64,30 +64,15 @@ struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd) > > return attrs; > } > -int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) > + > +int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr * iattr) > { > - struct inode * inode = dentry->d_inode; > - struct sysfs_dirent * sd = dentry->d_fsdata; > struct sysfs_inode_attrs *sd_attrs; > struct iattr *iattrs; > unsigned int ia_valid = iattr->ia_valid; > - int error; > - > - if (!sd) > - return -EINVAL; > > sd_attrs = sd->s_iattr; > > - error = inode_change_ok(inode, iattr); > - if (error) > - return error; > - > - iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */ > - > - error = inode_setattr(inode, iattr); > - if (error) > - return error; > - > if (!sd_attrs) { > /* setting attributes for the first time, allocate now */ > sd_attrs = sysfs_init_inode_attrs(sd); > @@ -110,12 +95,39 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) > iattrs->ia_ctime = iattr->ia_ctime; > if (ia_valid & ATTR_MODE) { > umode_t mode = iattr->ia_mode; > - > - if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) > - mode &= ~S_ISGID; > iattrs->ia_mode = sd->s_mode = mode; > } > } > + return 0; > +} > + > +int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) > +{ > + struct inode * inode = dentry->d_inode; > + struct sysfs_dirent * sd = dentry->d_fsdata; > + int error; > + > + if (!sd) > + return -EINVAL; > + > + error = inode_change_ok(inode, iattr); > + if (error) > + return error; > + > + iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */ > + if (iattr->ia_valid & ATTR_MODE) { > + if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) > + iattr->ia_mode &= ~S_ISGID; > + } Was it a bug that before this patch this wasn't cleared before the actual inode_setattr()? Since the S_ISGID will be set for the *new* gid, that is, iattr->ia_gid, shouldn't the user be required to be in_group_p(iattr->i_gid)? Note you haven't done the inode_setattr() yet. > + > + error = inode_setattr(inode, iattr); > + if (error) > + return error; > + > + mutex_lock(&sysfs_mutex); > + error = sysfs_sd_setattr(sd, iattr); > + mutex_unlock(&sysfs_mutex); > + > return error; > } > > diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h > index af4c4e7..a96d967 100644 > --- a/fs/sysfs/sysfs.h > +++ b/fs/sysfs/sysfs.h > @@ -155,6 +155,7 @@ static inline void __sysfs_put(struct sysfs_dirent *sd) > */ > struct inode *sysfs_get_inode(struct sysfs_dirent *sd); > void sysfs_delete_inode(struct inode *inode); > +int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr *iattr); > int sysfs_setattr(struct dentry *dentry, struct iattr *iattr); > int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value, > size_t size, int flags); > -- > 1.6.5.2.143.g8cc62 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
"Serge E. Hallyn" <serue@us.ibm.com> writes: > Quoting Eric W. Biederman (ebiederm@xmission.com): >> From: Eric W. Biederman <ebiederm@xmission.com> >> >> Cleanly separate the work that is specific to setting the >> attributes of a sysfs_dirent from what is needed to update >> the attributes of a vfs inode. >> >> Additionally grab the sysfs_mutex to keep any nasties from >> surprising us when updating the sysfs_dirent. >> >> Acked-by: Tejun Heo <tj@kernel.org> >> Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com> >> --- >> fs/sysfs/inode.c | 52 ++++++++++++++++++++++++++++++++-------------------- >> fs/sysfs/sysfs.h | 1 + >> 2 files changed, 33 insertions(+), 20 deletions(-) >> >> diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c >> index fed7a74..fccfb55 100644 >> --- a/fs/sysfs/inode.c >> +++ b/fs/sysfs/inode.c >> @@ -64,30 +64,15 @@ struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd) >> >> return attrs; >> } >> -int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) >> + >> +int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr * iattr) >> { >> - struct inode * inode = dentry->d_inode; >> - struct sysfs_dirent * sd = dentry->d_fsdata; >> struct sysfs_inode_attrs *sd_attrs; >> struct iattr *iattrs; >> unsigned int ia_valid = iattr->ia_valid; >> - int error; >> - >> - if (!sd) >> - return -EINVAL; >> >> sd_attrs = sd->s_iattr; >> >> - error = inode_change_ok(inode, iattr); >> - if (error) >> - return error; >> - >> - iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */ >> - >> - error = inode_setattr(inode, iattr); >> - if (error) >> - return error; >> - >> if (!sd_attrs) { >> /* setting attributes for the first time, allocate now */ >> sd_attrs = sysfs_init_inode_attrs(sd); >> @@ -110,12 +95,39 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) >> iattrs->ia_ctime = iattr->ia_ctime; >> if (ia_valid & ATTR_MODE) { >> umode_t mode = iattr->ia_mode; >> - >> - if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) >> - mode &= ~S_ISGID; >> iattrs->ia_mode = sd->s_mode = mode; >> } >> } >> + return 0; >> +} >> + >> +int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) >> +{ >> + struct inode * inode = dentry->d_inode; >> + struct sysfs_dirent * sd = dentry->d_fsdata; >> + int error; >> + >> + if (!sd) >> + return -EINVAL; >> + >> + error = inode_change_ok(inode, iattr); >> + if (error) >> + return error; >> + >> + iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */ >> + if (iattr->ia_valid & ATTR_MODE) { >> + if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) >> + iattr->ia_mode &= ~S_ISGID; >> + } > > Was it a bug that before this patch this wasn't cleared before the > actual inode_setattr()? Not strictly as inode_setattr performs the exact same check. > Since the S_ISGID will be set for the *new* gid, that is, > iattr->ia_gid, shouldn't the user be required to be > in_group_p(iattr->i_gid)? Note you haven't done the > inode_setattr() yet. Interesting point, yes I am potentially testing the wrong gid there. The dangers of moving code around. Thank you for catching that. !#@#!# Eric -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
ebiederm@xmission.com (Eric W. Biederman) writes: > "Serge E. Hallyn" <serue@us.ibm.com> writes: > >> Quoting Eric W. Biederman (ebiederm@xmission.com): >>> From: Eric W. Biederman <ebiederm@xmission.com> >>> >>> Cleanly separate the work that is specific to setting the >>> attributes of a sysfs_dirent from what is needed to update >>> the attributes of a vfs inode. >>> >>> Additionally grab the sysfs_mutex to keep any nasties from >>> surprising us when updating the sysfs_dirent. >>> >>> Acked-by: Tejun Heo <tj@kernel.org> >>> Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com> >>> --- >>> fs/sysfs/inode.c | 52 ++++++++++++++++++++++++++++++++-------------------- >>> fs/sysfs/sysfs.h | 1 + >>> 2 files changed, 33 insertions(+), 20 deletions(-) >>> >>> diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c >>> index fed7a74..fccfb55 100644 >>> --- a/fs/sysfs/inode.c >>> +++ b/fs/sysfs/inode.c >>> @@ -64,30 +64,15 @@ struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd) >>> >>> return attrs; >>> } >>> -int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) >>> + >>> +int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr * iattr) >>> { >>> - struct inode * inode = dentry->d_inode; >>> - struct sysfs_dirent * sd = dentry->d_fsdata; >>> struct sysfs_inode_attrs *sd_attrs; >>> struct iattr *iattrs; >>> unsigned int ia_valid = iattr->ia_valid; >>> - int error; >>> - >>> - if (!sd) >>> - return -EINVAL; >>> >>> sd_attrs = sd->s_iattr; >>> >>> - error = inode_change_ok(inode, iattr); >>> - if (error) >>> - return error; >>> - >>> - iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */ >>> - >>> - error = inode_setattr(inode, iattr); >>> - if (error) >>> - return error; >>> - >>> if (!sd_attrs) { >>> /* setting attributes for the first time, allocate now */ >>> sd_attrs = sysfs_init_inode_attrs(sd); >>> @@ -110,12 +95,39 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) >>> iattrs->ia_ctime = iattr->ia_ctime; >>> if (ia_valid & ATTR_MODE) { >>> umode_t mode = iattr->ia_mode; >>> - >>> - if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) >>> - mode &= ~S_ISGID; >>> iattrs->ia_mode = sd->s_mode = mode; >>> } >>> } >>> + return 0; >>> +} >>> + >>> +int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) >>> +{ >>> + struct inode * inode = dentry->d_inode; >>> + struct sysfs_dirent * sd = dentry->d_fsdata; >>> + int error; >>> + >>> + if (!sd) >>> + return -EINVAL; >>> + >>> + error = inode_change_ok(inode, iattr); >>> + if (error) >>> + return error; >>> + >>> + iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */ >>> + if (iattr->ia_valid & ATTR_MODE) { >>> + if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) >>> + iattr->ia_mode &= ~S_ISGID; >>> + } >> >> Was it a bug that before this patch this wasn't cleared before the >> actual inode_setattr()? > > Not strictly as inode_setattr performs the exact same check. > >> Since the S_ISGID will be set for the *new* gid, that is, >> iattr->ia_gid, shouldn't the user be required to be >> in_group_p(iattr->i_gid)? Note you haven't done the >> inode_setattr() yet. > > Interesting point, yes I am potentially testing the wrong gid > there. The dangers of moving code around. > > Thank you for catching that. !#@#!# Turns out it wasn't as bad as it looks because inode_change_ok already does what I am trying to do properly. Although come to think of it, SGID on a sysfs file is completely bogus. We don't exec files and we don't allow users to create anything. I have already sent the follow up patch to remove those few lines of code. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Patch
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c index fed7a74..fccfb55 100644 --- a/fs/sysfs/inode.c +++ b/fs/sysfs/inode.c @@ -64,30 +64,15 @@ struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd) return attrs; } -int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) + +int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr * iattr) { - struct inode * inode = dentry->d_inode; - struct sysfs_dirent * sd = dentry->d_fsdata; struct sysfs_inode_attrs *sd_attrs; struct iattr *iattrs; unsigned int ia_valid = iattr->ia_valid; - int error; - - if (!sd) - return -EINVAL; sd_attrs = sd->s_iattr; - error = inode_change_ok(inode, iattr); - if (error) - return error; - - iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */ - - error = inode_setattr(inode, iattr); - if (error) - return error; - if (!sd_attrs) { /* setting attributes for the first time, allocate now */ sd_attrs = sysfs_init_inode_attrs(sd); @@ -110,12 +95,39 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) iattrs->ia_ctime = iattr->ia_ctime; if (ia_valid & ATTR_MODE) { umode_t mode = iattr->ia_mode; - - if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) - mode &= ~S_ISGID; iattrs->ia_mode = sd->s_mode = mode; } } + return 0; +} + +int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) +{ + struct inode * inode = dentry->d_inode; + struct sysfs_dirent * sd = dentry->d_fsdata; + int error; + + if (!sd) + return -EINVAL; + + error = inode_change_ok(inode, iattr); + if (error) + return error; + + iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */ + if (iattr->ia_valid & ATTR_MODE) { + if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) + iattr->ia_mode &= ~S_ISGID; + } + + error = inode_setattr(inode, iattr); + if (error) + return error; + + mutex_lock(&sysfs_mutex); + error = sysfs_sd_setattr(sd, iattr); + mutex_unlock(&sysfs_mutex); + return error; } diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index af4c4e7..a96d967 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -155,6 +155,7 @@ static inline void __sysfs_put(struct sysfs_dirent *sd) */ struct inode *sysfs_get_inode(struct sysfs_dirent *sd); void sysfs_delete_inode(struct inode *inode); +int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr *iattr); int sysfs_setattr(struct dentry *dentry, struct iattr *iattr); int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags);