From 2322392b020badfe49730f1529b9c1a15248c387 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 23 Nov 2013 17:40:02 -0500 Subject: [PATCH] kernfs: implement "trusted.*" xattr support kernfs inherited "security.*" xattr support from sysfs. This patch extends xattr support to "trusted.*" using simple_xattr_*(). As trusted xattrs are restricted to CAP_SYS_ADMIN, simple_xattr_*() which uses kernel memory for storage shouldn't be problematic. Note that the existing "security.*" support doesn't implement get/remove/list and the this patch only implements those ops for "trusted.*". We probably want to extend those ops to include support for "security.*". This patch will allow using kernfs from cgroup which requires "trusted.*" xattr support. Signed-off-by: Tejun Heo Cc: David P. Quigley Signed-off-by: Greg Kroah-Hartman --- fs/kernfs/dir.c | 12 +++++-- fs/kernfs/inode.c | 63 ++++++++++++++++++++++++++++++++----- fs/kernfs/kernfs-internal.h | 7 +++++ fs/kernfs/symlink.c | 3 ++ 4 files changed, 74 insertions(+), 11 deletions(-) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index f51e0625e666..a441e3be8052 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -243,9 +243,12 @@ void kernfs_put(struct sysfs_dirent *sd) kernfs_put(sd->s_symlink.target_sd); if (sysfs_type(sd) & SYSFS_COPY_NAME) kfree(sd->s_name); - if (sd->s_iattr && sd->s_iattr->ia_secdata) - security_release_secctx(sd->s_iattr->ia_secdata, - sd->s_iattr->ia_secdata_len); + if (sd->s_iattr) { + if (sd->s_iattr->ia_secdata) + security_release_secctx(sd->s_iattr->ia_secdata, + sd->s_iattr->ia_secdata_len); + simple_xattrs_free(&sd->s_iattr->xattrs); + } kfree(sd->s_iattr); ida_simple_remove(&root->ino_ida, sd->s_ino); kmem_cache_free(sysfs_dir_cachep, sd); @@ -718,6 +721,9 @@ const struct inode_operations sysfs_dir_inode_operations = { .setattr = sysfs_setattr, .getattr = sysfs_getattr, .setxattr = sysfs_setxattr, + .removexattr = sysfs_removexattr, + .getxattr = sysfs_getxattr, + .listxattr = sysfs_listxattr, }; static struct sysfs_dirent *sysfs_leftmost_descendant(struct sysfs_dirent *pos) diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c index a1f83825afca..18ad431e8c2a 100644 --- a/fs/kernfs/inode.c +++ b/fs/kernfs/inode.c @@ -35,6 +35,9 @@ static const struct inode_operations sysfs_inode_operations = { .setattr = sysfs_setattr, .getattr = sysfs_getattr, .setxattr = sysfs_setxattr, + .removexattr = sysfs_removexattr, + .getxattr = sysfs_getxattr, + .listxattr = sysfs_listxattr, }; void __init sysfs_inode_init(void) @@ -61,6 +64,8 @@ static struct sysfs_inode_attrs *sysfs_inode_attrs(struct sysfs_dirent *sd) iattrs->ia_gid = GLOBAL_ROOT_GID; iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME; + simple_xattrs_init(&sd->s_iattr->xattrs); + return sd->s_iattr; } @@ -162,23 +167,25 @@ int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { struct sysfs_dirent *sd = dentry->d_fsdata; + struct sysfs_inode_attrs *attrs; void *secdata; int error; u32 secdata_len = 0; - if (!sd) - return -EINVAL; + attrs = sysfs_inode_attrs(sd); + if (!attrs) + return -ENOMEM; if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) { const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; error = security_inode_setsecurity(dentry->d_inode, suffix, value, size, flags); if (error) - goto out; + return error; error = security_inode_getsecctx(dentry->d_inode, &secdata, &secdata_len); if (error) - goto out; + return error; mutex_lock(&sysfs_mutex); error = sysfs_sd_setsecdata(sd, &secdata, &secdata_len); @@ -186,10 +193,50 @@ int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value, if (secdata) security_release_secctx(secdata, secdata_len); - } else - return -EINVAL; -out: - return error; + return error; + } else if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) { + return simple_xattr_set(&attrs->xattrs, name, value, size, + flags); + } + + return -EINVAL; +} + +int sysfs_removexattr(struct dentry *dentry, const char *name) +{ + struct sysfs_dirent *sd = dentry->d_fsdata; + struct sysfs_inode_attrs *attrs; + + attrs = sysfs_inode_attrs(sd); + if (!attrs) + return -ENOMEM; + + return simple_xattr_remove(&attrs->xattrs, name); +} + +ssize_t sysfs_getxattr(struct dentry *dentry, const char *name, void *buf, + size_t size) +{ + struct sysfs_dirent *sd = dentry->d_fsdata; + struct sysfs_inode_attrs *attrs; + + attrs = sysfs_inode_attrs(sd); + if (!attrs) + return -ENOMEM; + + return simple_xattr_get(&attrs->xattrs, name, buf, size); +} + +ssize_t sysfs_listxattr(struct dentry *dentry, char *buf, size_t size) +{ + struct sysfs_dirent *sd = dentry->d_fsdata; + struct sysfs_inode_attrs *attrs; + + attrs = sysfs_inode_attrs(sd); + if (!attrs) + return -ENOMEM; + + return simple_xattr_list(&attrs->xattrs, buf, size); } static inline void set_default_inode_attr(struct inode *inode, umode_t mode) diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index f25b3548bcca..910e485b7333 100644 --- a/fs/kernfs/kernfs-internal.h +++ b/fs/kernfs/kernfs-internal.h @@ -14,6 +14,7 @@ #include #include #include +#include #include @@ -21,6 +22,8 @@ struct sysfs_inode_attrs { struct iattr ia_iattr; void *ia_secdata; u32 ia_secdata_len; + + struct simple_xattrs xattrs; }; #define SD_DEACTIVATED_BIAS INT_MIN @@ -81,6 +84,10 @@ int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat); int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags); +int sysfs_removexattr(struct dentry *dentry, const char *name); +ssize_t sysfs_getxattr(struct dentry *dentry, const char *name, void *buf, + size_t size); +ssize_t sysfs_listxattr(struct dentry *dentry, char *buf, size_t size); void sysfs_inode_init(void); /* diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c index 12569a738837..adf28755b0ee 100644 --- a/fs/kernfs/symlink.c +++ b/fs/kernfs/symlink.c @@ -140,6 +140,9 @@ static void sysfs_put_link(struct dentry *dentry, struct nameidata *nd, const struct inode_operations sysfs_symlink_inode_operations = { .setxattr = sysfs_setxattr, + .removexattr = sysfs_removexattr, + .getxattr = sysfs_getxattr, + .listxattr = sysfs_listxattr, .readlink = generic_readlink, .follow_link = sysfs_follow_link, .put_link = sysfs_put_link, -- GitLab