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fs/xattr.c
23.5 KB
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// SPDX-License-Identifier: GPL-2.0-only |
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/* File: fs/xattr.c Extended attribute handling. Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org> Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com> Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> */ #include <linux/fs.h> #include <linux/slab.h> |
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#include <linux/file.h> #include <linux/xattr.h> |
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#include <linux/mount.h> |
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#include <linux/namei.h> #include <linux/security.h> |
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#include <linux/evm.h> |
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#include <linux/syscalls.h> |
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#include <linux/export.h> |
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#include <linux/fsnotify.h> |
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#include <linux/audit.h> |
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#include <linux/vmalloc.h> |
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#include <linux/posix_acl_xattr.h> |
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#include <linux/uaccess.h> |
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static const char * strcmp_prefix(const char *a, const char *a_prefix) { while (*a_prefix && *a == *a_prefix) { a++; a_prefix++; } return *a_prefix ? NULL : a; } /* * In order to implement different sets of xattr operations for each xattr |
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* prefix, a filesystem should create a null-terminated array of struct * xattr_handler (one for each prefix) and hang a pointer to it off of the * s_xattr field of the superblock. |
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*/ #define for_each_xattr_handler(handlers, handler) \ if (handlers) \ for ((handler) = *(handlers)++; \ (handler) != NULL; \ (handler) = *(handlers)++) /* * Find the xattr_handler with the matching prefix. */ static const struct xattr_handler * |
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xattr_resolve_name(struct inode *inode, const char **name) |
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{ |
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const struct xattr_handler **handlers = inode->i_sb->s_xattr; |
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const struct xattr_handler *handler; |
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if (!(inode->i_opflags & IOP_XATTR)) { if (unlikely(is_bad_inode(inode))) return ERR_PTR(-EIO); |
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return ERR_PTR(-EOPNOTSUPP); |
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} |
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for_each_xattr_handler(handlers, handler) { const char *n; n = strcmp_prefix(*name, xattr_prefix(handler)); if (n) { if (!handler->prefix ^ !*n) { if (*n) continue; return ERR_PTR(-EINVAL); } *name = n; return handler; } } return ERR_PTR(-EOPNOTSUPP); } |
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/* * Check permissions for extended attribute access. This is a bit complicated * because different namespaces have very different rules. */ static int xattr_permission(struct inode *inode, const char *name, int mask) { /* * We can never set or remove an extended attribute on a read-only * filesystem or on an immutable / append-only inode. */ if (mask & MAY_WRITE) { |
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if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) return -EPERM; |
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/* * Updating an xattr will likely cause i_uid and i_gid * to be writen back improperly if their true value is * unknown to the vfs. */ if (HAS_UNMAPPED_ID(inode)) return -EPERM; |
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} /* * No restriction for security.* and system.* from the VFS. Decision * on these is left to the underlying filesystem / security module. */ if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) || !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) return 0; /* |
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* The trusted.* namespace can only be accessed by privileged users. |
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*/ |
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if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) { if (!capable(CAP_SYS_ADMIN)) return (mask & MAY_WRITE) ? -EPERM : -ENODATA; return 0; } |
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/* * In the user.* namespace, only regular files and directories can have |
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* extended attributes. For sticky directories, only the owner and |
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* privileged users can write attributes. |
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*/ |
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if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { |
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if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) |
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return (mask & MAY_WRITE) ? -EPERM : -ENODATA; |
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if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && |
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(mask & MAY_WRITE) && !inode_owner_or_capable(inode)) |
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return -EPERM; } |
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return inode_permission(inode, mask); |
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} |
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int __vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name, const void *value, size_t size, int flags) { |
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const struct xattr_handler *handler; handler = xattr_resolve_name(inode, &name); if (IS_ERR(handler)) return PTR_ERR(handler); if (!handler->set) |
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return -EOPNOTSUPP; |
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if (size == 0) value = ""; /* empty EA, do not remove */ return handler->set(handler, dentry, inode, name, value, size, flags); |
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} EXPORT_SYMBOL(__vfs_setxattr); |
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/** * __vfs_setxattr_noperm - perform setxattr operation without performing * permission checks. * * @dentry - object to perform setxattr on * @name - xattr name to set * @value - value to set @name to * @size - size of @value * @flags - flags to pass into filesystem operations * * returns the result of the internal setxattr or setsecurity operations. * * This function requires the caller to lock the inode's i_mutex before it * is executed. It also assumes that the caller will make the appropriate * permission checks. */ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) |
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{ struct inode *inode = dentry->d_inode; |
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int error = -EAGAIN; |
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int issec = !strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN); |
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if (issec) inode->i_flags &= ~S_NOSEC; |
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if (inode->i_opflags & IOP_XATTR) { |
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error = __vfs_setxattr(dentry, inode, name, value, size, flags); |
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if (!error) { fsnotify_xattr(dentry); security_inode_post_setxattr(dentry, name, value, size, flags); } |
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} else { |
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if (unlikely(is_bad_inode(inode))) return -EIO; |
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} if (error == -EAGAIN) { error = -EOPNOTSUPP; if (issec) { const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; error = security_inode_setsecurity(inode, suffix, value, size, flags); if (!error) fsnotify_xattr(dentry); } |
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} |
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return error; } int vfs_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { struct inode *inode = dentry->d_inode; int error; error = xattr_permission(inode, name, MAY_WRITE); if (error) return error; |
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inode_lock(inode); |
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error = security_inode_setxattr(dentry, name, value, size, flags); if (error) goto out; error = __vfs_setxattr_noperm(dentry, name, value, size, flags); |
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out: |
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inode_unlock(inode); |
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return error; } EXPORT_SYMBOL_GPL(vfs_setxattr); |
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static ssize_t |
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xattr_getsecurity(struct inode *inode, const char *name, void *value, size_t size) { void *buffer = NULL; ssize_t len; if (!value || !size) { len = security_inode_getsecurity(inode, name, &buffer, false); goto out_noalloc; } len = security_inode_getsecurity(inode, name, &buffer, true); if (len < 0) return len; if (size < len) { len = -ERANGE; goto out; } memcpy(value, buffer, len); out: |
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kfree(buffer); |
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out_noalloc: return len; } |
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/* * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr * * Allocate memory, if not already allocated, or re-allocate correct size, * before retrieving the extended attribute. * * Returns the result of alloc, if failed, or the getxattr operation. */ ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value, size_t xattr_size, gfp_t flags) { |
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const struct xattr_handler *handler; |
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struct inode *inode = dentry->d_inode; char *value = *xattr_value; int error; error = xattr_permission(inode, name, MAY_READ); if (error) return error; |
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handler = xattr_resolve_name(inode, &name); if (IS_ERR(handler)) return PTR_ERR(handler); if (!handler->get) |
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return -EOPNOTSUPP; |
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error = handler->get(handler, dentry, inode, name, NULL, 0); |
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if (error < 0) return error; if (!value || (error > xattr_size)) { value = krealloc(*xattr_value, error + 1, flags); if (!value) return -ENOMEM; memset(value, 0, error + 1); } |
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error = handler->get(handler, dentry, inode, name, value, error); |
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*xattr_value = value; return error; } |
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ssize_t |
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__vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name, void *value, size_t size) { |
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const struct xattr_handler *handler; handler = xattr_resolve_name(inode, &name); if (IS_ERR(handler)) return PTR_ERR(handler); if (!handler->get) |
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return -EOPNOTSUPP; |
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return handler->get(handler, dentry, inode, name, value, size); |
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} EXPORT_SYMBOL(__vfs_getxattr); ssize_t |
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vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) |
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{ struct inode *inode = dentry->d_inode; int error; |
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error = xattr_permission(inode, name, MAY_READ); if (error) return error; |
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error = security_inode_getxattr(dentry, name); if (error) return error; |
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if (!strncmp(name, XATTR_SECURITY_PREFIX, |
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XATTR_SECURITY_PREFIX_LEN)) { const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; |
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int ret = xattr_getsecurity(inode, suffix, value, size); |
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/* * Only overwrite the return value if a security module * is actually active. */ |
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if (ret == -EOPNOTSUPP) goto nolsm; return ret; |
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} |
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nolsm: |
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return __vfs_getxattr(dentry, inode, name, value, size); |
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} EXPORT_SYMBOL_GPL(vfs_getxattr); |
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ssize_t |
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vfs_listxattr(struct dentry *dentry, char *list, size_t size) |
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{ |
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struct inode *inode = d_inode(dentry); |
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ssize_t error; |
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error = security_inode_listxattr(dentry); |
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if (error) return error; |
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if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) { |
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error = inode->i_op->listxattr(dentry, list, size); |
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} else { |
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error = security_inode_listsecurity(inode, list, size); |
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if (size && error > size) error = -ERANGE; } return error; } EXPORT_SYMBOL_GPL(vfs_listxattr); |
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int |
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__vfs_removexattr(struct dentry *dentry, const char *name) |
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{ |
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struct inode *inode = d_inode(dentry); const struct xattr_handler *handler; |
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handler = xattr_resolve_name(inode, &name); if (IS_ERR(handler)) return PTR_ERR(handler); if (!handler->set) |
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return -EOPNOTSUPP; |
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return handler->set(handler, dentry, inode, name, NULL, 0, XATTR_REPLACE); |
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} EXPORT_SYMBOL(__vfs_removexattr); int vfs_removexattr(struct dentry *dentry, const char *name) { struct inode *inode = dentry->d_inode; int error; |
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error = xattr_permission(inode, name, MAY_WRITE); if (error) return error; |
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inode_lock(inode); |
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error = security_inode_removexattr(dentry, name); |
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if (error) goto out; |
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error = __vfs_removexattr(dentry, name); |
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if (!error) { |
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fsnotify_xattr(dentry); |
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evm_inode_post_removexattr(dentry, name); } |
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out: |
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inode_unlock(inode); |
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return error; } EXPORT_SYMBOL_GPL(vfs_removexattr); |
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/* * Extended attribute SET operations */ static long |
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setxattr(struct dentry *d, const char __user *name, const void __user *value, |
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size_t size, int flags) { int error; void *kvalue = NULL; char kname[XATTR_NAME_MAX + 1]; if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) return -EINVAL; error = strncpy_from_user(kname, name, sizeof(kname)); if (error == 0 || error == sizeof(kname)) error = -ERANGE; if (error < 0) return error; if (size) { if (size > XATTR_SIZE_MAX) return -E2BIG; |
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kvalue = kvmalloc(size, GFP_KERNEL); if (!kvalue) return -ENOMEM; |
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if (copy_from_user(kvalue, value, size)) { error = -EFAULT; goto out; } |
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if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) posix_acl_fix_xattr_from_user(kvalue, size); |
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else if (strcmp(kname, XATTR_NAME_CAPS) == 0) { error = cap_convert_nscap(d, &kvalue, size); if (error < 0) goto out; size = error; } |
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} |
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error = vfs_setxattr(d, kname, kvalue, size, flags); |
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out: |
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kvfree(kvalue); |
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return error; } |
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static int path_setxattr(const char __user *pathname, const char __user *name, const void __user *value, size_t size, int flags, unsigned int lookup_flags) |
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{ |
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struct path path; |
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int error; |
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retry: error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); |
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if (error) return error; |
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error = mnt_want_write(path.mnt); |
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if (!error) { |
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error = setxattr(path.dentry, name, value, size, flags); mnt_drop_write(path.mnt); |
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} |
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path_put(&path); |
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if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; goto retry; } |
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return error; } |
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SYSCALL_DEFINE5(setxattr, const char __user *, pathname, const char __user *, name, const void __user *, value, size_t, size, int, flags) { return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW); } |
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SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname, const char __user *, name, const void __user *, value, size_t, size, int, flags) |
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{ |
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return path_setxattr(pathname, name, value, size, flags, 0); |
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} |
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SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, const void __user *,value, size_t, size, int, flags) |
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{ |
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struct fd f = fdget(fd); |
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int error = -EBADF; |
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if (!f.file) |
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return error; |
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audit_file(f.file); |
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error = mnt_want_write_file(f.file); |
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if (!error) { |
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error = setxattr(f.file->f_path.dentry, name, value, size, flags); |
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mnt_drop_write_file(f.file); |
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} |
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fdput(f); |
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return error; } /* * Extended attribute GET operations */ static ssize_t |
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getxattr(struct dentry *d, const char __user *name, void __user *value, size_t size) |
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{ ssize_t error; void *kvalue = NULL; char kname[XATTR_NAME_MAX + 1]; error = strncpy_from_user(kname, name, sizeof(kname)); if (error == 0 || error == sizeof(kname)) error = -ERANGE; if (error < 0) return error; if (size) { if (size > XATTR_SIZE_MAX) size = XATTR_SIZE_MAX; |
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kvalue = kvzalloc(size, GFP_KERNEL); if (!kvalue) return -ENOMEM; |
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} |
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error = vfs_getxattr(d, kname, kvalue, size); |
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if (error > 0) { |
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if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) |
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posix_acl_fix_xattr_to_user(kvalue, error); |
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if (size && copy_to_user(value, kvalue, error)) error = -EFAULT; } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { /* The file system tried to returned a value bigger than XATTR_SIZE_MAX bytes. Not possible. */ error = -E2BIG; |
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} |
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kvfree(kvalue); |
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return error; } |
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static ssize_t path_getxattr(const char __user *pathname, const char __user *name, void __user *value, size_t size, unsigned int lookup_flags) |
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{ |
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struct path path; |
1da177e4c
|
531 |
ssize_t error; |
60e66b48c
|
532 533 |
retry: error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); |
1da177e4c
|
534 535 |
if (error) return error; |
2d8f30380
|
536 537 |
error = getxattr(path.dentry, name, value, size); path_put(&path); |
60e66b48c
|
538 539 540 541 |
if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; goto retry; } |
1da177e4c
|
542 543 |
return error; } |
8cc431165
|
544 545 546 547 548 |
SYSCALL_DEFINE4(getxattr, const char __user *, pathname, const char __user *, name, void __user *, value, size_t, size) { return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW); } |
64fd1de3d
|
549 550 |
SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname, const char __user *, name, void __user *, value, size_t, size) |
1da177e4c
|
551 |
{ |
8cc431165
|
552 |
return path_getxattr(pathname, name, value, size, 0); |
1da177e4c
|
553 |
} |
64fd1de3d
|
554 555 |
SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, void __user *, value, size_t, size) |
1da177e4c
|
556 |
{ |
2903ff019
|
557 |
struct fd f = fdget(fd); |
1da177e4c
|
558 |
ssize_t error = -EBADF; |
2903ff019
|
559 |
if (!f.file) |
1da177e4c
|
560 |
return error; |
9f45f5bf3
|
561 |
audit_file(f.file); |
2903ff019
|
562 563 |
error = getxattr(f.file->f_path.dentry, name, value, size); fdput(f); |
1da177e4c
|
564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 |
return error; } /* * Extended attribute LIST operations */ static ssize_t listxattr(struct dentry *d, char __user *list, size_t size) { ssize_t error; char *klist = NULL; if (size) { if (size > XATTR_LIST_MAX) size = XATTR_LIST_MAX; |
752ade68c
|
579 580 581 |
klist = kvmalloc(size, GFP_KERNEL); if (!klist) return -ENOMEM; |
1da177e4c
|
582 |
} |
659564c8a
|
583 |
error = vfs_listxattr(d, klist, size); |
f549d6c18
|
584 585 586 587 588 589 590 |
if (error > 0) { if (size && copy_to_user(list, klist, error)) error = -EFAULT; } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { /* The file system tried to returned a list bigger than XATTR_LIST_MAX bytes. Not possible. */ error = -E2BIG; |
1da177e4c
|
591 |
} |
0b2a6f231
|
592 593 |
kvfree(klist); |
1da177e4c
|
594 595 |
return error; } |
8cc431165
|
596 597 |
static ssize_t path_listxattr(const char __user *pathname, char __user *list, size_t size, unsigned int lookup_flags) |
1da177e4c
|
598 |
{ |
2d8f30380
|
599 |
struct path path; |
1da177e4c
|
600 |
ssize_t error; |
10a90cf36
|
601 602 |
retry: error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); |
1da177e4c
|
603 604 |
if (error) return error; |
2d8f30380
|
605 606 |
error = listxattr(path.dentry, list, size); path_put(&path); |
10a90cf36
|
607 608 609 610 |
if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; goto retry; } |
1da177e4c
|
611 612 |
return error; } |
8cc431165
|
613 614 615 616 617 |
SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list, size_t, size) { return path_listxattr(pathname, list, size, LOOKUP_FOLLOW); } |
64fd1de3d
|
618 619 |
SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list, size_t, size) |
1da177e4c
|
620 |
{ |
8cc431165
|
621 |
return path_listxattr(pathname, list, size, 0); |
1da177e4c
|
622 |
} |
64fd1de3d
|
623 |
SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) |
1da177e4c
|
624 |
{ |
2903ff019
|
625 |
struct fd f = fdget(fd); |
1da177e4c
|
626 |
ssize_t error = -EBADF; |
2903ff019
|
627 |
if (!f.file) |
1da177e4c
|
628 |
return error; |
9f45f5bf3
|
629 |
audit_file(f.file); |
2903ff019
|
630 631 |
error = listxattr(f.file->f_path.dentry, list, size); fdput(f); |
1da177e4c
|
632 633 634 635 636 637 638 |
return error; } /* * Extended attribute REMOVE operations */ static long |
8f0cfa52a
|
639 |
removexattr(struct dentry *d, const char __user *name) |
1da177e4c
|
640 641 642 643 644 645 646 647 648 |
{ int error; char kname[XATTR_NAME_MAX + 1]; error = strncpy_from_user(kname, name, sizeof(kname)); if (error == 0 || error == sizeof(kname)) error = -ERANGE; if (error < 0) return error; |
5be196e5f
|
649 |
return vfs_removexattr(d, kname); |
1da177e4c
|
650 |
} |
8cc431165
|
651 652 |
static int path_removexattr(const char __user *pathname, const char __user *name, unsigned int lookup_flags) |
1da177e4c
|
653 |
{ |
2d8f30380
|
654 |
struct path path; |
1da177e4c
|
655 |
int error; |
12f062129
|
656 657 |
retry: error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); |
1da177e4c
|
658 659 |
if (error) return error; |
2d8f30380
|
660 |
error = mnt_want_write(path.mnt); |
18f335aff
|
661 |
if (!error) { |
2d8f30380
|
662 663 |
error = removexattr(path.dentry, name); mnt_drop_write(path.mnt); |
18f335aff
|
664 |
} |
2d8f30380
|
665 |
path_put(&path); |
12f062129
|
666 667 668 669 |
if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; goto retry; } |
1da177e4c
|
670 671 |
return error; } |
8cc431165
|
672 673 674 675 676 |
SYSCALL_DEFINE2(removexattr, const char __user *, pathname, const char __user *, name) { return path_removexattr(pathname, name, LOOKUP_FOLLOW); } |
6a6160a7b
|
677 678 |
SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, const char __user *, name) |
1da177e4c
|
679 |
{ |
8cc431165
|
680 |
return path_removexattr(pathname, name, 0); |
1da177e4c
|
681 |
} |
6a6160a7b
|
682 |
SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) |
1da177e4c
|
683 |
{ |
2903ff019
|
684 |
struct fd f = fdget(fd); |
1da177e4c
|
685 |
int error = -EBADF; |
2903ff019
|
686 |
if (!f.file) |
1da177e4c
|
687 |
return error; |
9f45f5bf3
|
688 |
audit_file(f.file); |
6742cee04
|
689 |
error = mnt_want_write_file(f.file); |
18f335aff
|
690 |
if (!error) { |
9f45f5bf3
|
691 |
error = removexattr(f.file->f_path.dentry, name); |
6742cee04
|
692 |
mnt_drop_write_file(f.file); |
18f335aff
|
693 |
} |
2903ff019
|
694 |
fdput(f); |
1da177e4c
|
695 696 |
return error; } |
1da177e4c
|
697 |
/* |
1da177e4c
|
698 699 700 701 702 703 |
* Combine the results of the list() operation from every xattr_handler in the * list. */ ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) { |
bb4354538
|
704 |
const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr; |
1da177e4c
|
705 706 707 |
unsigned int size = 0; if (!buffer) { |
431547b3c
|
708 |
for_each_xattr_handler(handlers, handler) { |
764a5c6b1
|
709 710 |
if (!handler->name || (handler->list && !handler->list(dentry))) |
c4803c497
|
711 |
continue; |
764a5c6b1
|
712 |
size += strlen(handler->name) + 1; |
431547b3c
|
713 |
} |
1da177e4c
|
714 715 |
} else { char *buf = buffer; |
764a5c6b1
|
716 |
size_t len; |
1da177e4c
|
717 718 |
for_each_xattr_handler(handlers, handler) { |
764a5c6b1
|
719 720 |
if (!handler->name || (handler->list && !handler->list(dentry))) |
c4803c497
|
721 |
continue; |
764a5c6b1
|
722 723 |
len = strlen(handler->name); if (len + 1 > buffer_size) |
1da177e4c
|
724 |
return -ERANGE; |
764a5c6b1
|
725 726 727 |
memcpy(buf, handler->name, len + 1); buf += len + 1; buffer_size -= len + 1; |
1da177e4c
|
728 729 730 731 732 |
} size = buf - buffer; } return size; } |
1da177e4c
|
733 |
EXPORT_SYMBOL(generic_listxattr); |
38f386574
|
734 |
|
e409de992
|
735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 |
/** * xattr_full_name - Compute full attribute name from suffix * * @handler: handler of the xattr_handler operation * @name: name passed to the xattr_handler operation * * The get and set xattr handler operations are called with the remainder of * the attribute name after skipping the handler's prefix: for example, "foo" * is passed to the get operation of a handler with prefix "user." to get * attribute "user.foo". The full name is still "there" in the name though. * * Note: the list xattr handler operation when called from the vfs is passed a * NULL name; some file systems use this operation internally, with varying * semantics. */ const char *xattr_full_name(const struct xattr_handler *handler, const char *name) { |
98e9cb571
|
753 |
size_t prefix_len = strlen(xattr_prefix(handler)); |
e409de992
|
754 755 756 757 |
return name - prefix_len; } EXPORT_SYMBOL(xattr_full_name); |
38f386574
|
758 759 760 761 762 763 764 765 766 767 |
/* * Allocate new xattr and copy in the value; but leave the name to callers. */ struct simple_xattr *simple_xattr_alloc(const void *value, size_t size) { struct simple_xattr *new_xattr; size_t len; /* wrap around? */ len = sizeof(*new_xattr) + size; |
4e66d445d
|
768 |
if (len < sizeof(*new_xattr)) |
38f386574
|
769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 |
return NULL; new_xattr = kmalloc(len, GFP_KERNEL); if (!new_xattr) return NULL; new_xattr->size = size; memcpy(new_xattr->value, value, size); return new_xattr; } /* * xattr GET operation for in-memory/pseudo filesystems */ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, void *buffer, size_t size) { struct simple_xattr *xattr; int ret = -ENODATA; spin_lock(&xattrs->lock); list_for_each_entry(xattr, &xattrs->head, list) { if (strcmp(name, xattr->name)) continue; ret = xattr->size; if (buffer) { if (size < xattr->size) ret = -ERANGE; else memcpy(buffer, xattr->value, xattr->size); } break; } spin_unlock(&xattrs->lock); return ret; } |
aa7c5241c
|
806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 |
/** * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems * @xattrs: target simple_xattr list * @name: name of the extended attribute * @value: value of the xattr. If %NULL, will remove the attribute. * @size: size of the new xattr * @flags: %XATTR_{CREATE|REPLACE} * * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist; * otherwise, fails with -ENODATA. * * Returns 0 on success, -errno on failure. */ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, const void *value, size_t size, int flags) |
38f386574
|
822 823 |
{ struct simple_xattr *xattr; |
433858469
|
824 |
struct simple_xattr *new_xattr = NULL; |
38f386574
|
825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 |
int err = 0; /* value == NULL means remove */ if (value) { new_xattr = simple_xattr_alloc(value, size); if (!new_xattr) return -ENOMEM; new_xattr->name = kstrdup(name, GFP_KERNEL); if (!new_xattr->name) { kfree(new_xattr); return -ENOMEM; } } spin_lock(&xattrs->lock); list_for_each_entry(xattr, &xattrs->head, list) { if (!strcmp(name, xattr->name)) { if (flags & XATTR_CREATE) { xattr = new_xattr; err = -EEXIST; } else if (new_xattr) { list_replace(&xattr->list, &new_xattr->list); } else { list_del(&xattr->list); } goto out; } } if (flags & XATTR_REPLACE) { xattr = new_xattr; err = -ENODATA; } else { list_add(&new_xattr->list, &xattrs->head); xattr = NULL; } out: spin_unlock(&xattrs->lock); if (xattr) { kfree(xattr->name); kfree(xattr); } return err; } |
38f386574
|
870 871 872 873 |
static bool xattr_is_trusted(const char *name) { return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); } |
786534b92
|
874 875 876 877 878 879 880 881 882 883 884 885 886 |
static int xattr_list_one(char **buffer, ssize_t *remaining_size, const char *name) { size_t len = strlen(name) + 1; if (*buffer) { if (*remaining_size < len) return -ERANGE; memcpy(*buffer, name, len); *buffer += len; } *remaining_size -= len; return 0; } |
38f386574
|
887 888 889 |
/* * xattr LIST operation for in-memory/pseudo filesystems */ |
786534b92
|
890 891 |
ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, char *buffer, size_t size) |
38f386574
|
892 893 894 |
{ bool trusted = capable(CAP_SYS_ADMIN); struct simple_xattr *xattr; |
786534b92
|
895 |
ssize_t remaining_size = size; |
0e9a7da51
|
896 |
int err = 0; |
786534b92
|
897 898 |
#ifdef CONFIG_FS_POSIX_ACL |
ffc4c9222
|
899 900 901 902 903 904 905 906 907 908 909 910 911 |
if (IS_POSIXACL(inode)) { if (inode->i_acl) { err = xattr_list_one(&buffer, &remaining_size, XATTR_NAME_POSIX_ACL_ACCESS); if (err) return err; } if (inode->i_default_acl) { err = xattr_list_one(&buffer, &remaining_size, XATTR_NAME_POSIX_ACL_DEFAULT); if (err) return err; } |
786534b92
|
912 913 |
} #endif |
38f386574
|
914 915 916 |
spin_lock(&xattrs->lock); list_for_each_entry(xattr, &xattrs->head, list) { |
38f386574
|
917 918 919 |
/* skip "trusted." attributes for unprivileged callers */ if (!trusted && xattr_is_trusted(xattr->name)) continue; |
786534b92
|
920 921 |
err = xattr_list_one(&buffer, &remaining_size, xattr->name); if (err) |
0e9a7da51
|
922 |
break; |
38f386574
|
923 924 |
} spin_unlock(&xattrs->lock); |
0e9a7da51
|
925 |
return err ? err : size - remaining_size; |
38f386574
|
926 |
} |
4895768b6
|
927 928 929 |
/* * Adds an extended attribute to the list */ |
38f386574
|
930 931 932 933 934 935 936 |
void simple_xattr_list_add(struct simple_xattrs *xattrs, struct simple_xattr *new_xattr) { spin_lock(&xattrs->lock); list_add(&new_xattr->list, &xattrs->head); spin_unlock(&xattrs->lock); } |