diff options
| -rw-r--r-- | fs/xattr.c | 166 | ||||
| -rw-r--r-- | include/linux/shmem_fs.h | 3 | ||||
| -rw-r--r-- | include/linux/xattr.h | 48 | ||||
| -rw-r--r-- | mm/shmem.c | 171 |
4 files changed, 229 insertions, 159 deletions
@@ -791,3 +791,169 @@ EXPORT_SYMBOL(generic_getxattr); EXPORT_SYMBOL(generic_listxattr); EXPORT_SYMBOL(generic_setxattr); EXPORT_SYMBOL(generic_removexattr); + +/* + * 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; + if (len <= sizeof(*new_xattr)) + 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; +} + +static int __simple_xattr_set(struct simple_xattrs *xattrs, const char *name, + const void *value, size_t size, int flags) +{ + struct simple_xattr *xattr; + struct simple_xattr *new_xattr = NULL; + 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; + +} + +/* + * xattr SET operation for in-memory/pseudo filesystems + */ +int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, + const void *value, size_t size, int flags) +{ + if (size == 0) + value = ""; /* empty EA, do not remove */ + return __simple_xattr_set(xattrs, name, value, size, flags); +} + +/* + * xattr REMOVE operation for in-memory/pseudo filesystems + */ +int simple_xattr_remove(struct simple_xattrs *xattrs, const char *name) +{ + return __simple_xattr_set(xattrs, name, NULL, 0, XATTR_REPLACE); +} + +static bool xattr_is_trusted(const char *name) +{ + return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); +} + +/* + * xattr LIST operation for in-memory/pseudo filesystems + */ +ssize_t simple_xattr_list(struct simple_xattrs *xattrs, char *buffer, + size_t size) +{ + bool trusted = capable(CAP_SYS_ADMIN); + struct simple_xattr *xattr; + size_t used = 0; + + spin_lock(&xattrs->lock); + list_for_each_entry(xattr, &xattrs->head, list) { + size_t len; + + /* skip "trusted." attributes for unprivileged callers */ + if (!trusted && xattr_is_trusted(xattr->name)) + continue; + + len = strlen(xattr->name) + 1; + used += len; + if (buffer) { + if (size < used) { + used = -ERANGE; + break; + } + memcpy(buffer, xattr->name, len); + buffer += len; + } + } + spin_unlock(&xattrs->lock); + + return used; +} + +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); +} diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index bef2cf0..30aa0dc 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -5,6 +5,7 @@ #include <linux/mempolicy.h> #include <linux/pagemap.h> #include <linux/percpu_counter.h> +#include <linux/xattr.h> /* inode in-kernel data */ @@ -18,7 +19,7 @@ struct shmem_inode_info { }; struct shared_policy policy; /* NUMA memory alloc policy */ struct list_head swaplist; /* chain of maybes on swap */ - struct list_head xattr_list; /* list of shmem_xattr */ + struct simple_xattrs xattrs; /* list of xattrs */ struct inode vfs_inode; }; diff --git a/include/linux/xattr.h b/include/linux/xattr.h index e5d1220..2ace7a6 100644 --- a/include/linux/xattr.h +++ b/include/linux/xattr.h @@ -59,7 +59,9 @@ #ifdef __KERNEL__ +#include <linux/slab.h> #include <linux/types.h> +#include <linux/spinlock.h> struct inode; struct dentry; @@ -96,6 +98,52 @@ ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value, size_t size, gfp_t flags); int vfs_xattr_cmp(struct dentry *dentry, const char *xattr_name, const char *value, size_t size, gfp_t flags); + +struct simple_xattrs { + struct list_head head; + spinlock_t lock; +}; + +struct simple_xattr { + struct list_head list; + char *name; + size_t size; + char value[0]; +}; + +/* + * initialize the simple_xattrs structure + */ +static inline void simple_xattrs_init(struct simple_xattrs *xattrs) +{ + INIT_LIST_HEAD(&xattrs->head); + spin_lock_init(&xattrs->lock); +} + +/* + * free all the xattrs + */ +static inline void simple_xattrs_free(struct simple_xattrs *xattrs) +{ + struct simple_xattr *xattr, *node; + + list_for_each_entry_safe(xattr, node, &xattrs->head, list) { + kfree(xattr->name); + kfree(xattr); + } +} + +struct simple_xattr *simple_xattr_alloc(const void *value, size_t size); +int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, + void *buffer, size_t size); +int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, + const void *value, size_t size, int flags); +int simple_xattr_remove(struct simple_xattrs *xattrs, const char *name); +ssize_t simple_xattr_list(struct simple_xattrs *xattrs, char *buffer, + size_t size); +void simple_xattr_list_add(struct simple_xattrs *xattrs, + struct simple_xattr *new_xattr); + #endif /* __KERNEL__ */ #endif /* _LINUX_XATTR_H */ @@ -77,13 +77,6 @@ static struct vfsmount *shm_mnt; /* Symlink up to this size is kmalloc'ed instead of using a swappable page */ #define SHORT_SYMLINK_LEN 128 -struct shmem_xattr { - struct list_head list; /* anchored by shmem_inode_info->xattr_list */ - char *name; /* xattr name */ - size_t size; - char value[0]; -}; - /* * shmem_fallocate and shmem_writepage communicate via inode->i_private * (with i_mutex making sure that it has only one user at a time): @@ -636,7 +629,6 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr) static void shmem_evict_inode(struct inode *inode) { struct shmem_inode_info *info = SHMEM_I(inode); - struct shmem_xattr *xattr, *nxattr; if (inode->i_mapping->a_ops == &shmem_aops) { shmem_unacct_size(info->flags, inode->i_size); @@ -650,10 +642,7 @@ static void shmem_evict_inode(struct inode *inode) } else kfree(info->symlink); - list_for_each_entry_safe(xattr, nxattr, &info->xattr_list, list) { - kfree(xattr->name); - kfree(xattr); - } + simple_xattrs_free(&info->xattrs); BUG_ON(inode->i_blocks); shmem_free_inode(inode->i_sb); clear_inode(inode); @@ -1377,7 +1366,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode spin_lock_init(&info->lock); info->flags = flags & VM_NORESERVE; INIT_LIST_HEAD(&info->swaplist); - INIT_LIST_HEAD(&info->xattr_list); + simple_xattrs_init(&info->xattrs); cache_no_acl(inode); switch (mode & S_IFMT) { @@ -2060,28 +2049,6 @@ static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *co */ /* - * Allocate new xattr and copy in the value; but leave the name to callers. - */ -static struct shmem_xattr *shmem_xattr_alloc(const void *value, size_t size) -{ - struct shmem_xattr *new_xattr; - size_t len; - - /* wrap around? */ - len = sizeof(*new_xattr) + size; - if (len <= sizeof(*new_xattr)) - 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; -} - -/* * Callback for security_inode_init_security() for acquiring xattrs. */ static int shmem_initxattrs(struct inode *inode, @@ -2090,11 +2057,11 @@ static int shmem_initxattrs(struct inode *inode, { struct shmem_inode_info *info = SHMEM_I(inode); const struct xattr *xattr; - struct shmem_xattr *new_xattr; + struct simple_xattr *new_xattr; size_t len; for (xattr = xattr_array; xattr->name != NULL; xattr++) { - new_xattr = shmem_xattr_alloc(xattr->value, xattr->value_len); + new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len); if (!new_xattr) return -ENOMEM; @@ -2111,91 +2078,12 @@ static int shmem_initxattrs(struct inode *inode, memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN, xattr->name, len); - spin_lock(&info->lock); - list_add(&new_xattr->list, &info->xattr_list); - spin_unlock(&info->lock); + simple_xattr_list_add(&info->xattrs, new_xattr); } return 0; } -static int shmem_xattr_get(struct dentry *dentry, const char *name, - void *buffer, size_t size) -{ - struct shmem_inode_info *info; - struct shmem_xattr *xattr; - int ret = -ENODATA; - - info = SHMEM_I(dentry->d_inode); - - spin_lock(&info->lock); - list_for_each_entry(xattr, &info->xattr_list, 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(&info->lock); - return ret; -} - -static int shmem_xattr_set(struct inode *inode, const char *name, - const void *value, size_t size, int flags) -{ - struct shmem_inode_info *info = SHMEM_I(inode); - struct shmem_xattr *xattr; - struct shmem_xattr *new_xattr = NULL; - int err = 0; - - /* value == NULL means remove */ - if (value) { - new_xattr = shmem_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(&info->lock); - list_for_each_entry(xattr, &info->xattr_list, 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, &info->xattr_list); - xattr = NULL; - } -out: - spin_unlock(&info->lock); - if (xattr) - kfree(xattr->name); - kfree(xattr); - return err; -} - static const struct xattr_handler *shmem_xattr_handlers[] = { #ifdef CONFIG_TMPFS_POSIX_ACL &generic_acl_access_handler, @@ -2226,6 +2114,7 @@ static int shmem_xattr_validate(const char *name) static ssize_t shmem_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size) { + struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); int err; /* @@ -2240,12 +2129,13 @@ static ssize_t shmem_getxattr(struct dentry *dentry, const char *name, if (err) return err; - return shmem_xattr_get(dentry, name, buffer, size); + return simple_xattr_get(&info->xattrs, name, buffer, size); } static int shmem_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { + struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); int err; /* @@ -2260,15 +2150,12 @@ static int shmem_setxattr(struct dentry *dentry, const char *name, if (err) return err; - if (size == 0) - value = ""; /* empty EA, do not remove */ - - return shmem_xattr_set(dentry->d_inode, name, value, size, flags); - + return simple_xattr_set(&info->xattrs, name, value, size, flags); } static int shmem_removexattr(struct dentry *dentry, const char *name) { + struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); int err; /* @@ -2283,45 +2170,13 @@ static int shmem_removexattr(struct dentry *dentry, const char *name) if (err) return err; - return shmem_xattr_set(dentry->d_inode, name, NULL, 0, XATTR_REPLACE); -} - -static bool xattr_is_trusted(const char *name) -{ - return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); + return simple_xattr_remove(&info->xattrs, name); } static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) { - bool trusted = capable(CAP_SYS_ADMIN); - struct shmem_xattr *xattr; - struct shmem_inode_info *info; - size_t used = 0; - - info = SHMEM_I(dentry->d_inode); - - spin_lock(&info->lock); - list_for_each_entry(xattr, &info->xattr_list, list) { - size_t len; - - /* skip "trusted." attributes for unprivileged callers */ - if (!trusted && xattr_is_trusted(xattr->name)) - continue; - - len = strlen(xattr->name) + 1; - used += len; - if (buffer) { - if (size < used) { - used = -ERANGE; - break; - } - memcpy(buffer, xattr->name, len); - buffer += len; - } - } - spin_unlock(&info->lock); - - return used; + struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); + return simple_xattr_list(&info->xattrs, buffer, size); } #endif /* CONFIG_TMPFS_XATTR */ |
