Messages in this thread Patch in this message | | | From | (Eric W. Biederman) | Date | Thu, 03 Jul 2008 18:11:40 -0700 | Subject | [PATCH 06/15] Introduce sysfs_sd_setattr and fix sysfs_chmod |
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Currently sysfs_chmod calls sys_setattr which in turn calls inode_change_ok which checks to see if it is ok for the current user space process to change tha attributes. Since sysfs_chmod_file has only kernel mode clients denying them permission if user space is the problem is completely inappropriate.
Therefore factor out sysfs_sd_setattr which does not call inode_change_ok and modify sysfs_chmod_file to call it.
In addition setting victim_sd->s_mode explicitly in sysfs_chmod_file is redundant so remove that as well.
Thanks to Tejun Heo <htejun@gmail.com>, and Daniel Lezcano <dlezcano@fr.ibm.com> for working on this and spotting this case.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> --- fs/sysfs/file.c | 5 +---- fs/sysfs/inode.c | 23 ++++++++++++++++------- fs/sysfs/sysfs.h | 1 + 3 files changed, 18 insertions(+), 11 deletions(-)
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index cb5dd3f..1304b3a 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -600,13 +600,10 @@ int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode) newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; newattrs.ia_ctime = current_fs_time(inode->i_sb); - rc = sysfs_setattr(victim, &newattrs); + rc = sysfs_sd_setattr(victim_sd, inode, &newattrs); if (rc == 0) { fsnotify_change(victim, newattrs.ia_valid); - mutex_lock(&sysfs_mutex); - victim_sd->s_mode = newattrs.ia_mode; - mutex_unlock(&sysfs_mutex); } mutex_unlock(&inode->i_mutex); diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c index eb53c63..80f8fd4 100644 --- a/fs/sysfs/inode.c +++ b/fs/sysfs/inode.c @@ -42,10 +42,9 @@ int __init sysfs_inode_init(void) return bdi_init(&sysfs_backing_dev_info); } -int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) +int sysfs_sd_setattr(struct sysfs_dirent *sd, struct inode *inode, + struct iattr * iattr) { - struct inode * inode = dentry->d_inode; - struct sysfs_dirent * sd = dentry->d_fsdata; struct iattr * sd_iattr; unsigned int ia_valid = iattr->ia_valid; int error; @@ -55,10 +54,6 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) sd_iattr = 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); @@ -104,6 +99,20 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) return error; } +int sysfs_setattr(struct dentry *dentry, struct iattr *iattr) +{ + struct inode * inode = dentry->d_inode; + struct sysfs_dirent * sd = dentry->d_fsdata; + int error; + + error = inode_change_ok(inode, iattr); + if (error) + return error; + + return sysfs_sd_setattr(sd, inode, iattr); +} + + static inline void set_default_inode_attr(struct inode * inode, mode_t mode) { inode->i_mode = mode; diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index b1bdc6e..5ee5d0a 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -154,6 +154,7 @@ static inline void sysfs_put(struct sysfs_dirent *sd) * inode.c */ struct inode *sysfs_get_inode(struct sysfs_dirent *sd); +int sysfs_sd_setattr(struct sysfs_dirent *sd, struct inode *inode, struct iattr *iattr); int sysfs_setattr(struct dentry *dentry, struct iattr *iattr); int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name); int sysfs_inode_init(void); -- 1.5.3.rc6.17.g1911
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