diff options
Diffstat (limited to 'fs/xattr.c')
| -rw-r--r-- | fs/xattr.c | 773 |
1 files changed, 595 insertions, 178 deletions
diff --git a/fs/xattr.c b/fs/xattr.c index 80eca7d3d69..c69e6d43a0d 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -9,16 +9,20 @@ */ #include <linux/fs.h> #include <linux/slab.h> -#include <linux/smp_lock.h> #include <linux/file.h> #include <linux/xattr.h> +#include <linux/mount.h> #include <linux/namei.h> #include <linux/security.h> +#include <linux/evm.h> #include <linux/syscalls.h> -#include <linux/module.h> +#include <linux/export.h> #include <linux/fsnotify.h> -#include <asm/uaccess.h> +#include <linux/audit.h> +#include <linux/vmalloc.h> +#include <linux/posix_acl_xattr.h> +#include <asm/uaccess.h> /* * Check permissions for extended attribute access. This is a bit complicated @@ -32,8 +36,6 @@ xattr_permission(struct inode *inode, const char *name, int mask) * filesystem or on an immutable / append-only inode. */ if (mask & MAY_WRITE) { - if (IS_RDONLY(inode)) - return -EROFS; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) return -EPERM; } @@ -47,36 +49,56 @@ xattr_permission(struct inode *inode, const char *name, int mask) return 0; /* - * The trusted.* namespace can only accessed by a privilegued user. + * The trusted.* namespace can only be accessed by privileged users. */ - if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) - return (capable(CAP_SYS_ADMIN) ? 0 : -EPERM); + if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) { + if (!capable(CAP_SYS_ADMIN)) + return (mask & MAY_WRITE) ? -EPERM : -ENODATA; + return 0; + } + /* + * In the user.* namespace, only regular files and directories can have + * extended attributes. For sticky directories, only the owner and + * privileged users can write attributes. + */ if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { - if (!S_ISREG(inode->i_mode) && - (!S_ISDIR(inode->i_mode) || inode->i_mode & S_ISVTX)) + if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) + return (mask & MAY_WRITE) ? -EPERM : -ENODATA; + if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && + (mask & MAY_WRITE) && !inode_owner_or_capable(inode)) return -EPERM; } - return permission(inode, mask, NULL); + return inode_permission(inode, mask); } -int -vfs_setxattr(struct dentry *dentry, char *name, void *value, - size_t size, int flags) +/** + * __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) { struct inode *inode = dentry->d_inode; - int error; - - error = xattr_permission(inode, name, MAY_WRITE); - if (error) - return error; + int error = -EOPNOTSUPP; + int issec = !strncmp(name, XATTR_SECURITY_PREFIX, + XATTR_SECURITY_PREFIX_LEN); - mutex_lock(&inode->i_mutex); - error = security_inode_setxattr(dentry, name, value, size, flags); - if (error) - goto out; - error = -EOPNOTSUPP; + if (issec) + inode->i_flags &= ~S_NOSEC; if (inode->i_op->setxattr) { error = inode->i_op->setxattr(dentry, name, value, size, flags); if (!error) { @@ -84,14 +106,36 @@ vfs_setxattr(struct dentry *dentry, char *name, void *value, security_inode_post_setxattr(dentry, name, value, size, flags); } - } else if (!strncmp(name, XATTR_SECURITY_PREFIX, - XATTR_SECURITY_PREFIX_LEN)) { + } else if (issec) { const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; error = security_inode_setsecurity(inode, suffix, value, size, flags); if (!error) fsnotify_xattr(dentry); } + + 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; + + mutex_lock(&inode->i_mutex); + error = security_inode_setxattr(dentry, name, value, size, flags); + if (error) + goto out; + + error = __vfs_setxattr_noperm(dentry, name, value, size, flags); + out: mutex_unlock(&inode->i_mutex); return error; @@ -99,43 +143,148 @@ out: EXPORT_SYMBOL_GPL(vfs_setxattr); ssize_t -vfs_getxattr(struct dentry *dentry, char *name, void *value, size_t size) +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: + security_release_secctx(buffer, len); +out_noalloc: + return len; +} +EXPORT_SYMBOL_GPL(xattr_getsecurity); + +/* + * 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) { struct inode *inode = dentry->d_inode; + char *value = *xattr_value; int error; error = xattr_permission(inode, name, MAY_READ); if (error) return error; - error = security_inode_getxattr(dentry, name); - if (error) + if (!inode->i_op->getxattr) + return -EOPNOTSUPP; + + error = inode->i_op->getxattr(dentry, name, NULL, 0); + if (error < 0) return error; - if (inode->i_op->getxattr) - error = inode->i_op->getxattr(dentry, name, value, size); + if (!value || (error > xattr_size)) { + value = krealloc(*xattr_value, error + 1, flags); + if (!value) + return -ENOMEM; + memset(value, 0, error + 1); + } + + error = inode->i_op->getxattr(dentry, name, value, error); + *xattr_value = value; + return error; +} + +/* Compare an extended attribute value with the given value */ +int vfs_xattr_cmp(struct dentry *dentry, const char *xattr_name, + const char *value, size_t size, gfp_t flags) +{ + char *xattr_value = NULL; + int rc; + + rc = vfs_getxattr_alloc(dentry, xattr_name, &xattr_value, 0, flags); + if (rc < 0) + return rc; + + if ((rc != size) || (memcmp(xattr_value, value, rc) != 0)) + rc = -EINVAL; else - error = -EOPNOTSUPP; + rc = 0; + kfree(xattr_value); + return rc; +} + +ssize_t +vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) +{ + struct inode *inode = dentry->d_inode; + int error; + + error = xattr_permission(inode, name, MAY_READ); + if (error) + return error; + + error = security_inode_getxattr(dentry, name); + if (error) + return error; if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) { const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; - int ret = security_inode_getsecurity(inode, suffix, value, - size, error); + int ret = xattr_getsecurity(inode, suffix, value, size); /* * Only overwrite the return value if a security module * is actually active. */ - if (ret != -EOPNOTSUPP) - error = ret; + if (ret == -EOPNOTSUPP) + goto nolsm; + return ret; } +nolsm: + if (inode->i_op->getxattr) + error = inode->i_op->getxattr(dentry, name, value, size); + else + error = -EOPNOTSUPP; return error; } EXPORT_SYMBOL_GPL(vfs_getxattr); +ssize_t +vfs_listxattr(struct dentry *d, char *list, size_t size) +{ + ssize_t error; + + error = security_inode_listxattr(d); + if (error) + return error; + error = -EOPNOTSUPP; + if (d->d_inode->i_op->listxattr) { + error = d->d_inode->i_op->listxattr(d, list, size); + } else { + error = security_inode_listsecurity(d->d_inode, list, size); + if (size && error > size) + error = -ERANGE; + } + return error; +} +EXPORT_SYMBOL_GPL(vfs_listxattr); + int -vfs_removexattr(struct dentry *dentry, char *name) +vfs_removexattr(struct dentry *dentry, const char *name) { struct inode *inode = dentry->d_inode; int error; @@ -147,16 +296,20 @@ vfs_removexattr(struct dentry *dentry, char *name) if (error) return error; + mutex_lock(&inode->i_mutex); error = security_inode_removexattr(dentry, name); - if (error) + if (error) { + mutex_unlock(&inode->i_mutex); return error; + } - mutex_lock(&inode->i_mutex); error = inode->i_op->removexattr(dentry, name); mutex_unlock(&inode->i_mutex); - if (!error) + if (!error) { fsnotify_xattr(dentry); + evm_inode_post_removexattr(dentry, name); + } return error; } EXPORT_SYMBOL_GPL(vfs_removexattr); @@ -166,11 +319,12 @@ EXPORT_SYMBOL_GPL(vfs_removexattr); * Extended attribute SET operations */ static long -setxattr(struct dentry *d, char __user *name, void __user *value, +setxattr(struct dentry *d, const char __user *name, const void __user *value, size_t size, int flags) { int error; void *kvalue = NULL; + void *vvalue = NULL; /* If non-NULL, we used vmalloc() */ char kname[XATTR_NAME_MAX + 1]; if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) @@ -185,62 +339,96 @@ setxattr(struct dentry *d, char __user *name, void __user *value, if (size) { if (size > XATTR_SIZE_MAX) return -E2BIG; - kvalue = kmalloc(size, GFP_KERNEL); - if (!kvalue) - return -ENOMEM; + kvalue = kmalloc(size, GFP_KERNEL | __GFP_NOWARN); + if (!kvalue) { + vvalue = vmalloc(size); + if (!vvalue) + return -ENOMEM; + kvalue = vvalue; + } if (copy_from_user(kvalue, value, size)) { - kfree(kvalue); - return -EFAULT; + error = -EFAULT; + goto out; } + 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); } error = vfs_setxattr(d, kname, kvalue, size, flags); - kfree(kvalue); +out: + if (vvalue) + vfree(vvalue); + else + kfree(kvalue); return error; } -asmlinkage long -sys_setxattr(char __user *path, char __user *name, void __user *value, - size_t size, int flags) +SYSCALL_DEFINE5(setxattr, const char __user *, pathname, + const char __user *, name, const void __user *, value, + size_t, size, int, flags) { - struct nameidata nd; + struct path path; int error; - - error = user_path_walk(path, &nd); + unsigned int lookup_flags = LOOKUP_FOLLOW; +retry: + error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); if (error) return error; - error = setxattr(nd.dentry, name, value, size, flags); - path_release(&nd); + error = mnt_want_write(path.mnt); + if (!error) { + error = setxattr(path.dentry, name, value, size, flags); + mnt_drop_write(path.mnt); + } + path_put(&path); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } return error; } -asmlinkage long -sys_lsetxattr(char __user *path, char __user *name, void __user *value, - size_t size, int flags) +SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname, + const char __user *, name, const void __user *, value, + size_t, size, int, flags) { - struct nameidata nd; + struct path path; int error; - - error = user_path_walk_link(path, &nd); + unsigned int lookup_flags = 0; +retry: + error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); if (error) return error; - error = setxattr(nd.dentry, name, value, size, flags); - path_release(&nd); + error = mnt_want_write(path.mnt); + if (!error) { + error = setxattr(path.dentry, name, value, size, flags); + mnt_drop_write(path.mnt); + } + path_put(&path); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } return error; } -asmlinkage long -sys_fsetxattr(int fd, char __user *name, void __user *value, - size_t size, int flags) +SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, + const void __user *,value, size_t, size, int, flags) { - struct file *f; + struct fd f = fdget(fd); + struct dentry *dentry; int error = -EBADF; - f = fget(fd); - if (!f) + if (!f.file) return error; - error = setxattr(f->f_dentry, name, value, size, flags); - fput(f); + dentry = f.file->f_path.dentry; + audit_inode(NULL, dentry, 0); + error = mnt_want_write_file(f.file); + if (!error) { + error = setxattr(dentry, name, value, size, flags); + mnt_drop_write_file(f.file); + } + fdput(f); return error; } @@ -248,10 +436,12 @@ sys_fsetxattr(int fd, char __user *name, void __user *value, * Extended attribute GET operations */ static ssize_t -getxattr(struct dentry *d, char __user *name, void __user *value, size_t size) +getxattr(struct dentry *d, const char __user *name, void __user *value, + size_t size) { ssize_t error; void *kvalue = NULL; + void *vvalue = NULL; char kname[XATTR_NAME_MAX + 1]; error = strncpy_from_user(kname, name, sizeof(kname)); @@ -263,13 +453,20 @@ getxattr(struct dentry *d, char __user *name, void __user *value, size_t size) if (size) { if (size > XATTR_SIZE_MAX) size = XATTR_SIZE_MAX; - kvalue = kzalloc(size, GFP_KERNEL); - if (!kvalue) - return -ENOMEM; + kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); + if (!kvalue) { + vvalue = vmalloc(size); + if (!vvalue) + return -ENOMEM; + kvalue = vvalue; + } } error = vfs_getxattr(d, kname, kvalue, size); if (error > 0) { + if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || + (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) + posix_acl_fix_xattr_to_user(kvalue, size); if (size && copy_to_user(value, kvalue, error)) error = -EFAULT; } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { @@ -277,51 +474,62 @@ getxattr(struct dentry *d, char __user *name, void __user *value, size_t size) than XATTR_SIZE_MAX bytes. Not possible. */ error = -E2BIG; } - kfree(kvalue); + if (vvalue) + vfree(vvalue); + else + kfree(kvalue); return error; } -asmlinkage ssize_t -sys_getxattr(char __user *path, char __user *name, void __user *value, - size_t size) +SYSCALL_DEFINE4(getxattr, const char __user *, pathname, + const char __user *, name, void __user *, value, size_t, size) { - struct nameidata nd; + struct path path; ssize_t error; - - error = user_path_walk(path, &nd); + unsigned int lookup_flags = LOOKUP_FOLLOW; +retry: + error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); if (error) return error; - error = getxattr(nd.dentry, name, value, size); - path_release(&nd); + error = getxattr(path.dentry, name, value, size); + path_put(&path); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } return error; } -asmlinkage ssize_t -sys_lgetxattr(char __user *path, char __user *name, void __user *value, - size_t size) +SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname, + const char __user *, name, void __user *, value, size_t, size) { - struct nameidata nd; + struct path path; ssize_t error; - - error = user_path_walk_link(path, &nd); + unsigned int lookup_flags = 0; +retry: + error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); if (error) return error; - error = getxattr(nd.dentry, name, value, size); - path_release(&nd); + error = getxattr(path.dentry, name, value, size); + path_put(&path); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } return error; } -asmlinkage ssize_t -sys_fgetxattr(int fd, char __user *name, void __user *value, size_t size) +SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, + void __user *, value, size_t, size) { - struct file *f; + struct fd f = fdget(fd); ssize_t error = -EBADF; - f = fget(fd); - if (!f) + if (!f.file) return error; - error = getxattr(f->f_dentry, name, value, size); - fput(f); + audit_inode(NULL, f.file->f_path.dentry, 0); + error = getxattr(f.file->f_path.dentry, name, value, size); + fdput(f); return error; } @@ -333,26 +541,21 @@ listxattr(struct dentry *d, char __user *list, size_t size) { ssize_t error; char *klist = NULL; + char *vlist = NULL; /* If non-NULL, we used vmalloc() */ if (size) { if (size > XATTR_LIST_MAX) size = XATTR_LIST_MAX; - klist = kmalloc(size, GFP_KERNEL); - if (!klist) - return -ENOMEM; + klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL); + if (!klist) { + vlist = vmalloc(size); + if (!vlist) + return -ENOMEM; + klist = vlist; + } } - error = security_inode_listxattr(d); - if (error) - goto out; - error = -EOPNOTSUPP; - if (d->d_inode->i_op && d->d_inode->i_op->listxattr) { - error = d->d_inode->i_op->listxattr(d, klist, size); - } else { - error = security_inode_listsecurity(d->d_inode, klist, size); - if (size && error > size) - error = -ERANGE; - } + error = vfs_listxattr(d, klist, size); if (error > 0) { if (size && copy_to_user(list, klist, error)) error = -EFAULT; @@ -361,50 +564,61 @@ listxattr(struct dentry *d, char __user *list, size_t size) than XATTR_LIST_MAX bytes. Not possible. */ error = -E2BIG; } -out: - kfree(klist); + if (vlist) + vfree(vlist); + else + kfree(klist); return error; } -asmlinkage ssize_t -sys_listxattr(char __user *path, char __user *list, size_t size) +SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list, + size_t, size) { - struct nameidata nd; + struct path path; ssize_t error; - - error = user_path_walk(path, &nd); + unsigned int lookup_flags = LOOKUP_FOLLOW; +retry: + error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); if (error) return error; - error = listxattr(nd.dentry, list, size); - path_release(&nd); + error = listxattr(path.dentry, list, size); + path_put(&path); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } return error; } -asmlinkage ssize_t -sys_llistxattr(char __user *path, char __user *list, size_t size) +SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list, + size_t, size) { - struct nameidata nd; + struct path path; ssize_t error; - - error = user_path_walk_link(path, &nd); + unsigned int lookup_flags = 0; +retry: + error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); if (error) return error; - error = listxattr(nd.dentry, list, size); - path_release(&nd); + error = listxattr(path.dentry, list, size); + path_put(&path); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } return error; } -asmlinkage ssize_t -sys_flistxattr(int fd, char __user *list, size_t size) +SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) { - struct file *f; + struct fd f = fdget(fd); ssize_t error = -EBADF; - f = fget(fd); - if (!f) + if (!f.file) return error; - error = listxattr(f->f_dentry, list, size); - fput(f); + audit_inode(NULL, f.file->f_path.dentry, 0); + error = listxattr(f.file->f_path.dentry, list, size); + fdput(f); return error; } @@ -412,7 +626,7 @@ sys_flistxattr(int fd, char __user *list, size_t size) * Extended attribute REMOVE operations */ static long -removexattr(struct dentry *d, char __user *name) +removexattr(struct dentry *d, const char __user *name) { int error; char kname[XATTR_NAME_MAX + 1]; @@ -426,45 +640,68 @@ removexattr(struct dentry *d, char __user *name) return vfs_removexattr(d, kname); } -asmlinkage long -sys_removexattr(char __user *path, char __user *name) +SYSCALL_DEFINE2(removexattr, const char __user *, pathname, + const char __user *, name) { - struct nameidata nd; + struct path path; int error; - - error = user_path_walk(path, &nd); + unsigned int lookup_flags = LOOKUP_FOLLOW; +retry: + error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); if (error) return error; - error = removexattr(nd.dentry, name); - path_release(&nd); + error = mnt_want_write(path.mnt); + if (!error) { + error = removexattr(path.dentry, name); + mnt_drop_write(path.mnt); + } + path_put(&path); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } return error; } -asmlinkage long -sys_lremovexattr(char __user *path, char __user *name) +SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, + const char __user *, name) { - struct nameidata nd; + struct path path; int error; - - error = user_path_walk_link(path, &nd); + unsigned int lookup_flags = 0; +retry: + error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); if (error) return error; - error = removexattr(nd.dentry, name); - path_release(&nd); + error = mnt_want_write(path.mnt); + if (!error) { + error = removexattr(path.dentry, name); + mnt_drop_write(path.mnt); + } + path_put(&path); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } return error; } -asmlinkage long -sys_fremovexattr(int fd, char __user *name) +SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) { - struct file *f; + struct fd f = fdget(fd); + struct dentry *dentry; int error = -EBADF; - f = fget(fd); - if (!f) + if (!f.file) return error; - error = removexattr(f->f_dentry, name); - fput(f); + dentry = f.file->f_path.dentry; + audit_inode(NULL, dentry, 0); + error = mnt_want_write_file(f.file); + if (!error) { + error = removexattr(dentry, name); + mnt_drop_write_file(f.file); + } + fdput(f); return error; } @@ -496,10 +733,10 @@ strcmp_prefix(const char *a, const char *a_prefix) /* * Find the xattr_handler with the matching prefix. */ -static struct xattr_handler * -xattr_resolve_name(struct xattr_handler **handlers, const char **name) +static const struct xattr_handler * +xattr_resolve_name(const struct xattr_handler **handlers, const char **name) { - struct xattr_handler *handler; + const struct xattr_handler *handler; if (!*name) return NULL; @@ -520,13 +757,12 @@ xattr_resolve_name(struct xattr_handler **handlers, const char **name) ssize_t generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size) { - struct xattr_handler *handler; - struct inode *inode = dentry->d_inode; + const struct xattr_handler *handler; - handler = xattr_resolve_name(inode->i_sb->s_xattr, &name); + handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); if (!handler) return -EOPNOTSUPP; - return handler->get(inode, name, buffer, size); + return handler->get(dentry, name, buffer, size, handler->flags); } /* @@ -536,18 +772,20 @@ generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t s ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) { - struct inode *inode = dentry->d_inode; - struct xattr_handler *handler, **handlers = inode->i_sb->s_xattr; + const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr; unsigned int size = 0; if (!buffer) { - for_each_xattr_handler(handlers, handler) - size += handler->list(inode, NULL, 0, NULL, 0); + for_each_xattr_handler(handlers, handler) { + size += handler->list(dentry, NULL, 0, NULL, 0, + handler->flags); + } } else { char *buf = buffer; for_each_xattr_handler(handlers, handler) { - size = handler->list(inode, buf, buffer_size, NULL, 0); + size = handler->list(dentry, buf, buffer_size, + NULL, 0, handler->flags); if (size > buffer_size) return -ERANGE; buf += size; @@ -564,15 +802,14 @@ 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) { - struct xattr_handler *handler; - struct inode *inode = dentry->d_inode; + const struct xattr_handler *handler; if (size == 0) value = ""; /* empty EA, do not remove */ - handler = xattr_resolve_name(inode->i_sb->s_xattr, &name); + handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); if (!handler) return -EOPNOTSUPP; - return handler->set(inode, name, value, size, flags); + return handler->set(dentry, name, value, size, flags, handler->flags); } /* @@ -582,16 +819,196 @@ generic_setxattr(struct dentry *dentry, const char *name, const void *value, siz int generic_removexattr(struct dentry *dentry, const char *name) { - struct xattr_handler *handler; - struct inode *inode = dentry->d_inode; + const struct xattr_handler *handler; - handler = xattr_resolve_name(inode->i_sb->s_xattr, &name); + handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); if (!handler) return -EOPNOTSUPP; - return handler->set(inode, name, NULL, 0, XATTR_REPLACE); + return handler->set(dentry, name, NULL, 0, + XATTR_REPLACE, handler->flags); } 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; + +} + +/** + * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems + * @xattrs: target simple_xattr list + * @name: name of the new extended attribute + * @value: value of the new 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) +{ + 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; +} + +/* + * Adds an extended attribute to the list + */ +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); +} |