From 5be196e5f925dab2309530fabce69c2e562b9791 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 9 Jan 2006 20:51:55 -0800 Subject: [PATCH] [PATCH] add vfs_* helpers for xattr operations Add vfs_getxattr, vfs_setxattr and vfs_removexattr helpers for common checks around invocation of the xattr methods. NFSD already was missing some of the checks and there will be more soon. Signed-off-by: Christoph Hellwig Cc: James Morris (James, I haven't touched selinux yet because it's doing various odd things and I'm not sure how it would interact with the security attribute fallbacks you added. Could you investigate whether it could use vfs_getxattr or if not add a __vfs_getxattr helper to share the bits it is fine with?) For NFSv4: instead of just converting it add an nfsd_getxattr helper for the code shared by NFSv2/3 and NFSv4 ACLs. In fact that code isn't even NFS-specific, but I'll wait for more users to pop up first before moving it to common code. Signed-off-by: Christoph Hellwig Acked-by: Dave Kleikamp Signed-off-by: Adrian Bunk Signed-off-by: Neil Brown Cc: Trond Myklebust Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/nfsd/vfs.c | 125 ++++++++++++++---------------------- fs/xattr.c | 146 +++++++++++++++++++++++++++--------------- include/linux/xattr.h | 4 ++ 3 files changed, 145 insertions(+), 130 deletions(-) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index bb36b4304491..eef0576a7785 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -48,8 +48,8 @@ #include #include #include -#ifdef CONFIG_NFSD_V4 #include +#ifdef CONFIG_NFSD_V4 #include #include #include @@ -365,8 +365,30 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap, goto out; } -#if defined(CONFIG_NFSD_V4) +#if defined(CONFIG_NFSD_V2_ACL) || \ + defined(CONFIG_NFSD_V3_ACL) || \ + defined(CONFIG_NFSD_V4) +static ssize_t nfsd_getxattr(struct dentry *dentry, char *key, void **buf) +{ + ssize_t buflen; + int error; + buflen = vfs_getxattr(dentry, key, NULL, 0); + if (buflen <= 0) + return buflen; + + *buf = kmalloc(buflen, GFP_KERNEL); + if (!*buf) + return -ENOMEM; + + error = vfs_getxattr(dentry, key, *buf, buflen); + if (error < 0) + return error; + return buflen; +} +#endif + +#if defined(CONFIG_NFSD_V4) static int set_nfsv4_acl_one(struct dentry *dentry, struct posix_acl *pacl, char *key) { @@ -374,7 +396,6 @@ set_nfsv4_acl_one(struct dentry *dentry, struct posix_acl *pacl, char *key) size_t buflen; char *buf = NULL; int error = 0; - struct inode *inode = dentry->d_inode; buflen = posix_acl_xattr_size(pacl->a_count); buf = kmalloc(buflen, GFP_KERNEL); @@ -388,15 +409,7 @@ set_nfsv4_acl_one(struct dentry *dentry, struct posix_acl *pacl, char *key) goto out; } - error = -EOPNOTSUPP; - if (inode->i_op && inode->i_op->setxattr) { - mutex_lock(&inode->i_mutex); - security_inode_setxattr(dentry, key, buf, len, 0); - error = inode->i_op->setxattr(dentry, key, buf, len, 0); - if (!error) - security_inode_post_setxattr(dentry, key, buf, len, 0); - mutex_unlock(&inode->i_mutex); - } + error = vfs_setxattr(dentry, key, buf, len, 0); out: kfree(buf); return error; @@ -455,44 +468,19 @@ nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp, static struct posix_acl * _get_posix_acl(struct dentry *dentry, char *key) { - struct inode *inode = dentry->d_inode; - char *buf = NULL; - int buflen, error = 0; + void *buf = NULL; struct posix_acl *pacl = NULL; + int buflen; - error = -EOPNOTSUPP; - if (inode->i_op == NULL) - goto out_err; - if (inode->i_op->getxattr == NULL) - goto out_err; - - error = security_inode_getxattr(dentry, key); - if (error) - goto out_err; - - buflen = inode->i_op->getxattr(dentry, key, NULL, 0); - if (buflen <= 0) { - error = buflen < 0 ? buflen : -ENODATA; - goto out_err; - } - - buf = kmalloc(buflen, GFP_KERNEL); - if (buf == NULL) { - error = -ENOMEM; - goto out_err; - } - - error = inode->i_op->getxattr(dentry, key, buf, buflen); - if (error < 0) - goto out_err; + buflen = nfsd_getxattr(dentry, key, &buf); + if (!buflen) + buflen = -ENODATA; + if (buflen <= 0) + return ERR_PTR(buflen); pacl = posix_acl_from_xattr(buf, buflen); - out: kfree(buf); return pacl; - out_err: - pacl = ERR_PTR(error); - goto out; } int @@ -1884,39 +1872,25 @@ nfsd_get_posix_acl(struct svc_fh *fhp, int type) ssize_t size; struct posix_acl *acl; - if (!IS_POSIXACL(inode) || !inode->i_op || !inode->i_op->getxattr) + if (!IS_POSIXACL(inode)) + return ERR_PTR(-EOPNOTSUPP); + + switch (type) { + case ACL_TYPE_ACCESS: + name = POSIX_ACL_XATTR_ACCESS; + break; + case ACL_TYPE_DEFAULT: + name = POSIX_ACL_XATTR_DEFAULT; + break; + default: return ERR_PTR(-EOPNOTSUPP); - switch(type) { - case ACL_TYPE_ACCESS: - name = POSIX_ACL_XATTR_ACCESS; - break; - case ACL_TYPE_DEFAULT: - name = POSIX_ACL_XATTR_DEFAULT; - break; - default: - return ERR_PTR(-EOPNOTSUPP); } - size = inode->i_op->getxattr(fhp->fh_dentry, name, NULL, 0); + size = nfsd_getxattr(fhp->fh_dentry, name, &value); + if (size < 0) + return ERR_PTR(size); - if (size < 0) { - acl = ERR_PTR(size); - goto getout; - } else if (size > 0) { - value = kmalloc(size, GFP_KERNEL); - if (!value) { - acl = ERR_PTR(-ENOMEM); - goto getout; - } - size = inode->i_op->getxattr(fhp->fh_dentry, name, value, size); - if (size < 0) { - acl = ERR_PTR(size); - goto getout; - } - } acl = posix_acl_from_xattr(value, size); - -getout: kfree(value); return acl; } @@ -1957,16 +1931,13 @@ nfsd_set_posix_acl(struct svc_fh *fhp, int type, struct posix_acl *acl) } else size = 0; - if (!fhp->fh_locked) - fh_lock(fhp); /* unlocking is done automatically */ if (size) - error = inode->i_op->setxattr(fhp->fh_dentry, name, - value, size, 0); + error = vfs_setxattr(fhp->fh_dentry, name, value, size, 0); else { if (!S_ISDIR(inode->i_mode) && type == ACL_TYPE_DEFAULT) error = 0; else { - error = inode->i_op->removexattr(fhp->fh_dentry, name); + error = vfs_removexattr(fhp->fh_dentry, name); if (error == -ENODATA) error = 0; } diff --git a/fs/xattr.c b/fs/xattr.c index 386a532ee5a9..fee804e69a9a 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -19,6 +19,96 @@ #include #include + +int +vfs_setxattr(struct dentry *dentry, char *name, void *value, + size_t size, int flags) +{ + struct inode *inode = dentry->d_inode; + int error; + + mutex_lock(&inode->i_mutex); + error = security_inode_setxattr(dentry, name, value, size, flags); + if (error) + goto out; + error = -EOPNOTSUPP; + if (inode->i_op->setxattr) { + error = inode->i_op->setxattr(dentry, name, value, size, flags); + if (!error) { + fsnotify_xattr(dentry); + security_inode_post_setxattr(dentry, name, value, + size, flags); + } + } else if (!strncmp(name, XATTR_SECURITY_PREFIX, + sizeof XATTR_SECURITY_PREFIX - 1)) { + const char *suffix = name + sizeof XATTR_SECURITY_PREFIX - 1; + error = security_inode_setsecurity(inode, suffix, value, + size, flags); + if (!error) + fsnotify_xattr(dentry); + } +out: + mutex_unlock(&inode->i_mutex); + return error; +} +EXPORT_SYMBOL_GPL(vfs_setxattr); + +ssize_t +vfs_getxattr(struct dentry *dentry, char *name, void *value, size_t size) +{ + struct inode *inode = dentry->d_inode; + int error; + + error = security_inode_getxattr(dentry, name); + if (error) + return error; + + if (inode->i_op->getxattr) + error = inode->i_op->getxattr(dentry, name, value, size); + else + error = -EOPNOTSUPP; + + if (!strncmp(name, XATTR_SECURITY_PREFIX, + sizeof XATTR_SECURITY_PREFIX - 1)) { + const char *suffix = name + sizeof XATTR_SECURITY_PREFIX - 1; + int ret = security_inode_getsecurity(inode, suffix, value, + size, error); + /* + * Only overwrite the return value if a security module + * is actually active. + */ + if (ret != -EOPNOTSUPP) + error = ret; + } + + return error; +} +EXPORT_SYMBOL_GPL(vfs_getxattr); + +int +vfs_removexattr(struct dentry *dentry, char *name) +{ + struct inode *inode = dentry->d_inode; + int error; + + if (!inode->i_op->removexattr) + return -EOPNOTSUPP; + + error = security_inode_removexattr(dentry, name); + if (error) + return error; + + mutex_lock(&inode->i_mutex); + error = inode->i_op->removexattr(dentry, name); + mutex_unlock(&inode->i_mutex); + + if (!error) + fsnotify_xattr(dentry); + return error; +} +EXPORT_SYMBOL_GPL(vfs_removexattr); + + /* * Extended attribute SET operations */ @@ -51,29 +141,7 @@ setxattr(struct dentry *d, char __user *name, void __user *value, } } - mutex_lock(&d->d_inode->i_mutex); - error = security_inode_setxattr(d, kname, kvalue, size, flags); - if (error) - goto out; - error = -EOPNOTSUPP; - if (d->d_inode->i_op && d->d_inode->i_op->setxattr) { - error = d->d_inode->i_op->setxattr(d, kname, kvalue, - size, flags); - if (!error) { - fsnotify_xattr(d); - security_inode_post_setxattr(d, kname, kvalue, - size, flags); - } - } else if (!strncmp(kname, XATTR_SECURITY_PREFIX, - sizeof XATTR_SECURITY_PREFIX - 1)) { - const char *suffix = kname + sizeof XATTR_SECURITY_PREFIX - 1; - error = security_inode_setsecurity(d->d_inode, suffix, kvalue, - size, flags); - if (!error) - fsnotify_xattr(d); - } -out: - mutex_unlock(&d->d_inode->i_mutex); + error = vfs_setxattr(d, kname, kvalue, size, flags); kfree(kvalue); return error; } @@ -147,22 +215,7 @@ getxattr(struct dentry *d, char __user *name, void __user *value, size_t size) return -ENOMEM; } - error = security_inode_getxattr(d, kname); - if (error) - goto out; - error = -EOPNOTSUPP; - if (d->d_inode->i_op && d->d_inode->i_op->getxattr) - error = d->d_inode->i_op->getxattr(d, kname, kvalue, size); - - if (!strncmp(kname, XATTR_SECURITY_PREFIX, - sizeof XATTR_SECURITY_PREFIX - 1)) { - const char *suffix = kname + sizeof XATTR_SECURITY_PREFIX - 1; - int rv = security_inode_getsecurity(d->d_inode, suffix, kvalue, - size, error); - /* Security module active: overwrite error value */ - if (rv != -EOPNOTSUPP) - error = rv; - } + error = vfs_getxattr(d, kname, kvalue, size); if (error > 0) { if (size && copy_to_user(value, kvalue, error)) error = -EFAULT; @@ -171,7 +224,6 @@ getxattr(struct dentry *d, char __user *name, void __user *value, size_t size) than XATTR_SIZE_MAX bytes. Not possible. */ error = -E2BIG; } -out: kfree(kvalue); return error; } @@ -318,19 +370,7 @@ removexattr(struct dentry *d, char __user *name) if (error < 0) return error; - error = -EOPNOTSUPP; - if (d->d_inode->i_op && d->d_inode->i_op->removexattr) { - error = security_inode_removexattr(d, kname); - if (error) - goto out; - mutex_lock(&d->d_inode->i_mutex); - error = d->d_inode->i_op->removexattr(d, kname); - mutex_unlock(&d->d_inode->i_mutex); - if (!error) - fsnotify_xattr(d); - } -out: - return error; + return vfs_removexattr(d, kname); } asmlinkage long diff --git a/include/linux/xattr.h b/include/linux/xattr.h index 23f9c61d9546..366f0ab4219f 100644 --- a/include/linux/xattr.h +++ b/include/linux/xattr.h @@ -25,6 +25,10 @@ struct xattr_handler { size_t size, int flags); }; +ssize_t vfs_getxattr(struct dentry *, char *, void *, size_t); +int vfs_setxattr(struct dentry *, char *, void *, size_t, int); +int vfs_removexattr(struct dentry *, char *); + ssize_t generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size); ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size); int generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags);