diff options
Diffstat (limited to 'fs/xattr.c')
-rw-r--r-- | fs/xattr.c | 407 |
1 files changed, 302 insertions, 105 deletions
diff --git a/fs/xattr.c b/fs/xattr.c index 90dd78f0eb27..61107b6bbed2 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -25,6 +25,8 @@ #include <linux/uaccess.h> +#include "internal.h" + static const char * strcmp_prefix(const char *a, const char *a_prefix) { @@ -83,7 +85,8 @@ xattr_resolve_name(struct inode *inode, const char **name) * because different namespaces have very different rules. */ static int -xattr_permission(struct inode *inode, const char *name, int mask) +xattr_permission(struct user_namespace *mnt_userns, struct inode *inode, + const char *name, int mask) { /* * We can never set or remove an extended attribute on a read-only @@ -97,7 +100,7 @@ xattr_permission(struct inode *inode, const char *name, int mask) * to be writen back improperly if their true value is * unknown to the vfs. */ - if (HAS_UNMAPPED_ID(inode)) + if (HAS_UNMAPPED_ID(mnt_userns, inode)) return -EPERM; } @@ -127,16 +130,45 @@ xattr_permission(struct inode *inode, const char *name, int mask) 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)) + (mask & MAY_WRITE) && + !inode_owner_or_capable(mnt_userns, inode)) return -EPERM; } - return inode_permission(inode, mask); + return inode_permission(mnt_userns, inode, mask); +} + +/* + * Look for any handler that deals with the specified namespace. + */ +int +xattr_supported_namespace(struct inode *inode, const char *prefix) +{ + const struct xattr_handler **handlers = inode->i_sb->s_xattr; + const struct xattr_handler *handler; + size_t preflen; + + if (!(inode->i_opflags & IOP_XATTR)) { + if (unlikely(is_bad_inode(inode))) + return -EIO; + return -EOPNOTSUPP; + } + + preflen = strlen(prefix); + + for_each_xattr_handler(handlers, handler) { + if (!strncmp(xattr_prefix(handler), prefix, preflen)) + return 0; + } + + return -EOPNOTSUPP; } +EXPORT_SYMBOL(xattr_supported_namespace); int -__vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name, - const void *value, size_t size, int flags) +__vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, + struct inode *inode, const char *name, const void *value, + size_t size, int flags) { const struct xattr_handler *handler; @@ -147,7 +179,8 @@ __vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name, return -EOPNOTSUPP; if (size == 0) value = ""; /* empty EA, do not remove */ - return handler->set(handler, dentry, inode, name, value, size, flags); + return handler->set(handler, mnt_userns, dentry, inode, name, value, + size, flags); } EXPORT_SYMBOL(__vfs_setxattr); @@ -155,11 +188,12 @@ EXPORT_SYMBOL(__vfs_setxattr); * __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 + * @mnt_userns: user namespace of the mount the inode was found from + * @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. * @@ -167,8 +201,9 @@ EXPORT_SYMBOL(__vfs_setxattr); * 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) +int __vfs_setxattr_noperm(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *name, + const void *value, size_t size, int flags) { struct inode *inode = dentry->d_inode; int error = -EAGAIN; @@ -178,7 +213,8 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, if (issec) inode->i_flags &= ~S_NOSEC; if (inode->i_opflags & IOP_XATTR) { - error = __vfs_setxattr(dentry, inode, name, value, size, flags); + error = __vfs_setxattr(mnt_userns, dentry, inode, name, value, + size, flags); if (!error) { fsnotify_xattr(dentry); security_inode_post_setxattr(dentry, name, value, @@ -204,44 +240,103 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, return error; } - +/** + * __vfs_setxattr_locked - set an extended attribute while holding the inode + * lock + * + * @mnt_userns: user namespace of the mount of the target inode + * @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 + * @delegated_inode: on return, will contain an inode pointer that + * a delegation was broken on, NULL if none. + */ int -vfs_setxattr(struct dentry *dentry, const char *name, const void *value, - size_t size, int flags) +__vfs_setxattr_locked(struct user_namespace *mnt_userns, struct dentry *dentry, + const char *name, const void *value, size_t size, + int flags, struct inode **delegated_inode) { struct inode *inode = dentry->d_inode; int error; - error = xattr_permission(inode, name, MAY_WRITE); + error = xattr_permission(mnt_userns, inode, name, MAY_WRITE); if (error) return error; - inode_lock(inode); - error = security_inode_setxattr(dentry, name, value, size, flags); + error = security_inode_setxattr(mnt_userns, dentry, name, value, size, + flags); if (error) goto out; - error = __vfs_setxattr_noperm(dentry, name, value, size, flags); + error = try_break_deleg(inode, delegated_inode); + if (error) + goto out; + + error = __vfs_setxattr_noperm(mnt_userns, dentry, name, value, + size, flags); out: + return error; +} +EXPORT_SYMBOL_GPL(__vfs_setxattr_locked); + +static inline bool is_posix_acl_xattr(const char *name) +{ + return (strcmp(name, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || + (strcmp(name, XATTR_NAME_POSIX_ACL_DEFAULT) == 0); +} + +int +vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, + const char *name, const void *value, size_t size, int flags) +{ + struct inode *inode = dentry->d_inode; + struct inode *delegated_inode = NULL; + const void *orig_value = value; + int error; + + if (size && strcmp(name, XATTR_NAME_CAPS) == 0) { + error = cap_convert_nscap(mnt_userns, dentry, &value, size); + if (error < 0) + return error; + size = error; + } + +retry_deleg: + inode_lock(inode); + error = __vfs_setxattr_locked(mnt_userns, dentry, name, value, size, + flags, &delegated_inode); inode_unlock(inode); + + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } + if (value != orig_value) + kfree(value); + return error; } EXPORT_SYMBOL_GPL(vfs_setxattr); static ssize_t -xattr_getsecurity(struct inode *inode, const char *name, void *value, - size_t size) +xattr_getsecurity(struct user_namespace *mnt_userns, 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); + len = security_inode_getsecurity(mnt_userns, inode, name, + &buffer, false); goto out_noalloc; } - len = security_inode_getsecurity(inode, name, &buffer, true); + len = security_inode_getsecurity(mnt_userns, inode, name, &buffer, + true); if (len < 0) return len; if (size < len) { @@ -264,15 +359,16 @@ out_noalloc: * 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) +vfs_getxattr_alloc(struct user_namespace *mnt_userns, struct dentry *dentry, + const char *name, char **xattr_value, size_t xattr_size, + gfp_t flags) { const struct xattr_handler *handler; struct inode *inode = dentry->d_inode; char *value = *xattr_value; int error; - error = xattr_permission(inode, name, MAY_READ); + error = xattr_permission(mnt_userns, inode, name, MAY_READ); if (error) return error; @@ -313,12 +409,13 @@ __vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name, EXPORT_SYMBOL(__vfs_getxattr); ssize_t -vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) +vfs_getxattr(struct user_namespace *mnt_userns, 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); + error = xattr_permission(mnt_userns, inode, name, MAY_READ); if (error) return error; @@ -329,7 +426,8 @@ vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) { const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; - int ret = xattr_getsecurity(inode, suffix, value, size); + int ret = xattr_getsecurity(mnt_userns, inode, suffix, value, + size); /* * Only overwrite the return value if a security module * is actually active. @@ -339,7 +437,10 @@ vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) return ret; } nolsm: - return __vfs_getxattr(dentry, inode, name, value, size); + error = __vfs_getxattr(dentry, inode, name, value, size); + if (error > 0 && is_posix_acl_xattr(name)) + posix_acl_getxattr_idmapped_mnt(mnt_userns, inode, value, size); + return error; } EXPORT_SYMBOL_GPL(vfs_getxattr); @@ -364,7 +465,8 @@ vfs_listxattr(struct dentry *dentry, char *list, size_t size) EXPORT_SYMBOL_GPL(vfs_listxattr); int -__vfs_removexattr(struct dentry *dentry, const char *name) +__vfs_removexattr(struct user_namespace *mnt_userns, struct dentry *dentry, + const char *name) { struct inode *inode = d_inode(dentry); const struct xattr_handler *handler; @@ -374,26 +476,42 @@ __vfs_removexattr(struct dentry *dentry, const char *name) return PTR_ERR(handler); if (!handler->set) return -EOPNOTSUPP; - return handler->set(handler, dentry, inode, name, NULL, 0, XATTR_REPLACE); + return handler->set(handler, mnt_userns, dentry, inode, name, NULL, 0, + XATTR_REPLACE); } EXPORT_SYMBOL(__vfs_removexattr); +/** + * __vfs_removexattr_locked - set an extended attribute while holding the inode + * lock + * + * @mnt_userns: user namespace of the mount of the target inode + * @dentry: object to perform setxattr on + * @name: name of xattr to remove + * @delegated_inode: on return, will contain an inode pointer that + * a delegation was broken on, NULL if none. + */ int -vfs_removexattr(struct dentry *dentry, const char *name) +__vfs_removexattr_locked(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *name, + struct inode **delegated_inode) { struct inode *inode = dentry->d_inode; int error; - error = xattr_permission(inode, name, MAY_WRITE); + error = xattr_permission(mnt_userns, inode, name, MAY_WRITE); if (error) return error; - inode_lock(inode); - error = security_inode_removexattr(dentry, name); + error = security_inode_removexattr(mnt_userns, dentry, name); + if (error) + goto out; + + error = try_break_deleg(inode, delegated_inode); if (error) goto out; - error = __vfs_removexattr(dentry, name); + error = __vfs_removexattr(mnt_userns, dentry, name); if (!error) { fsnotify_xattr(dentry); @@ -401,57 +519,104 @@ vfs_removexattr(struct dentry *dentry, const char *name) } out: + return error; +} +EXPORT_SYMBOL_GPL(__vfs_removexattr_locked); + +int +vfs_removexattr(struct user_namespace *mnt_userns, struct dentry *dentry, + const char *name) +{ + struct inode *inode = dentry->d_inode; + struct inode *delegated_inode = NULL; + int error; + +retry_deleg: + inode_lock(inode); + error = __vfs_removexattr_locked(mnt_userns, dentry, + name, &delegated_inode); inode_unlock(inode); + + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } + return error; } EXPORT_SYMBOL_GPL(vfs_removexattr); - /* * Extended attribute SET operations */ -static long -setxattr(struct dentry *d, const char __user *name, const void __user *value, - size_t size, int flags) + +int setxattr_copy(const char __user *name, struct xattr_ctx *ctx) { int error; - void *kvalue = NULL; - char kname[XATTR_NAME_MAX + 1]; - if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) + if (ctx->flags & ~(XATTR_CREATE|XATTR_REPLACE)) return -EINVAL; - error = strncpy_from_user(kname, name, sizeof(kname)); - if (error == 0 || error == sizeof(kname)) - error = -ERANGE; + error = strncpy_from_user(ctx->kname->name, name, + sizeof(ctx->kname->name)); + if (error == 0 || error == sizeof(ctx->kname->name)) + return -ERANGE; if (error < 0) return error; - if (size) { - if (size > XATTR_SIZE_MAX) + error = 0; + if (ctx->size) { + if (ctx->size > XATTR_SIZE_MAX) return -E2BIG; - kvalue = kvmalloc(size, GFP_KERNEL); - if (!kvalue) - return -ENOMEM; - if (copy_from_user(kvalue, value, size)) { - 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); - else if (strcmp(kname, XATTR_NAME_CAPS) == 0) { - error = cap_convert_nscap(d, &kvalue, size); - if (error < 0) - goto out; - size = error; + + ctx->kvalue = vmemdup_user(ctx->cvalue, ctx->size); + if (IS_ERR(ctx->kvalue)) { + error = PTR_ERR(ctx->kvalue); + ctx->kvalue = NULL; } } - error = vfs_setxattr(d, kname, kvalue, size, flags); -out: - kvfree(kvalue); + return error; +} + +static void setxattr_convert(struct user_namespace *mnt_userns, + struct dentry *d, struct xattr_ctx *ctx) +{ + if (ctx->size && is_posix_acl_xattr(ctx->kname->name)) + posix_acl_fix_xattr_from_user(ctx->kvalue, ctx->size); +} + +int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, + struct xattr_ctx *ctx) +{ + setxattr_convert(mnt_userns, dentry, ctx); + return vfs_setxattr(mnt_userns, dentry, ctx->kname->name, + ctx->kvalue, ctx->size, ctx->flags); +} + +static long +setxattr(struct user_namespace *mnt_userns, struct dentry *d, + const char __user *name, const void __user *value, size_t size, + int flags) +{ + struct xattr_name kname; + struct xattr_ctx ctx = { + .cvalue = value, + .kvalue = NULL, + .size = size, + .kname = &kname, + .flags = flags, + }; + int error; + + error = setxattr_copy(name, &ctx); + if (error) + return error; + error = do_setxattr(mnt_userns, d, &ctx); + + kvfree(ctx.kvalue); return error; } @@ -461,13 +626,15 @@ static int path_setxattr(const char __user *pathname, { struct path path; int error; + retry: error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); if (error) return error; error = mnt_want_write(path.mnt); if (!error) { - error = setxattr(path.dentry, name, value, size, flags); + error = setxattr(mnt_user_ns(path.mnt), path.dentry, name, + value, size, flags); mnt_drop_write(path.mnt); } path_put(&path); @@ -503,7 +670,9 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, audit_file(f.file); error = mnt_want_write_file(f.file); if (!error) { - error = setxattr(f.file->f_path.dentry, name, value, size, flags); + error = setxattr(file_mnt_user_ns(f.file), + f.file->f_path.dentry, name, + value, size, flags); mnt_drop_write_file(f.file); } fdput(f); @@ -513,43 +682,59 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, /* * Extended attribute GET operations */ -static ssize_t -getxattr(struct dentry *d, const char __user *name, void __user *value, - size_t size) +ssize_t +do_getxattr(struct user_namespace *mnt_userns, struct dentry *d, + struct xattr_ctx *ctx) { ssize_t error; - void *kvalue = NULL; - char kname[XATTR_NAME_MAX + 1]; + char *kname = ctx->kname->name; - 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; - kvalue = kvzalloc(size, GFP_KERNEL); - if (!kvalue) + if (ctx->size) { + if (ctx->size > XATTR_SIZE_MAX) + ctx->size = XATTR_SIZE_MAX; + ctx->kvalue = kvzalloc(ctx->size, GFP_KERNEL); + if (!ctx->kvalue) return -ENOMEM; } - error = vfs_getxattr(d, kname, kvalue, size); + error = vfs_getxattr(mnt_userns, d, kname, ctx->kvalue, ctx->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, error); - if (size && copy_to_user(value, kvalue, error)) + if (is_posix_acl_xattr(kname)) + posix_acl_fix_xattr_to_user(ctx->kvalue, error); + if (ctx->size && copy_to_user(ctx->value, ctx->kvalue, error)) error = -EFAULT; - } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { + } else if (error == -ERANGE && ctx->size >= XATTR_SIZE_MAX) { /* The file system tried to returned a value bigger than XATTR_SIZE_MAX bytes. Not possible. */ error = -E2BIG; } - kvfree(kvalue); + return error; +} + +static ssize_t +getxattr(struct user_namespace *mnt_userns, struct dentry *d, + const char __user *name, void __user *value, size_t size) +{ + ssize_t error; + struct xattr_name kname; + struct xattr_ctx ctx = { + .value = value, + .kvalue = NULL, + .size = size, + .kname = &kname, + .flags = 0, + }; + + error = strncpy_from_user(kname.name, name, sizeof(kname.name)); + if (error == 0 || error == sizeof(kname.name)) + error = -ERANGE; + if (error < 0) + return error; + + error = do_getxattr(mnt_userns, d, &ctx); + kvfree(ctx.kvalue); return error; } @@ -563,7 +748,7 @@ retry: error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); if (error) return error; - error = getxattr(path.dentry, name, value, size); + error = getxattr(mnt_user_ns(path.mnt), path.dentry, name, value, size); path_put(&path); if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; @@ -593,7 +778,8 @@ SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, if (!f.file) return error; audit_file(f.file); - error = getxattr(f.file->f_path.dentry, name, value, size); + error = getxattr(file_mnt_user_ns(f.file), f.file->f_path.dentry, + name, value, size); fdput(f); return error; } @@ -677,7 +863,8 @@ SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) * Extended attribute REMOVE operations */ static long -removexattr(struct dentry *d, const char __user *name) +removexattr(struct user_namespace *mnt_userns, struct dentry *d, + const char __user *name) { int error; char kname[XATTR_NAME_MAX + 1]; @@ -688,7 +875,7 @@ removexattr(struct dentry *d, const char __user *name) if (error < 0) return error; - return vfs_removexattr(d, kname); + return vfs_removexattr(mnt_userns, d, kname); } static int path_removexattr(const char __user *pathname, @@ -702,7 +889,7 @@ retry: return error; error = mnt_want_write(path.mnt); if (!error) { - error = removexattr(path.dentry, name); + error = removexattr(mnt_user_ns(path.mnt), path.dentry, name); mnt_drop_write(path.mnt); } path_put(&path); @@ -735,7 +922,8 @@ SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) audit_file(f.file); error = mnt_want_write_file(f.file); if (!error) { - error = removexattr(f.file->f_path.dentry, name); + error = removexattr(file_mnt_user_ns(f.file), + f.file->f_path.dentry, name); mnt_drop_write_file(f.file); } fdput(f); @@ -817,7 +1005,7 @@ struct simple_xattr *simple_xattr_alloc(const void *value, size_t size) if (len < sizeof(*new_xattr)) return NULL; - new_xattr = kmalloc(len, GFP_KERNEL); + new_xattr = kvmalloc(len, GFP_KERNEL); if (!new_xattr) return NULL; @@ -860,6 +1048,7 @@ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, * @value: value of the xattr. If %NULL, will remove the attribute. * @size: size of the new xattr * @flags: %XATTR_{CREATE|REPLACE} + * @removed_size: returns size of the removed xattr, -1 if none removed * * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist; @@ -868,12 +1057,16 @@ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, * 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) + const void *value, size_t size, int flags, + ssize_t *removed_size) { struct simple_xattr *xattr; struct simple_xattr *new_xattr = NULL; int err = 0; + if (removed_size) + *removed_size = -1; + /* value == NULL means remove */ if (value) { new_xattr = simple_xattr_alloc(value, size); @@ -882,7 +1075,7 @@ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, new_xattr->name = kstrdup(name, GFP_KERNEL); if (!new_xattr->name) { - kfree(new_xattr); + kvfree(new_xattr); return -ENOMEM; } } @@ -895,8 +1088,12 @@ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, err = -EEXIST; } else if (new_xattr) { list_replace(&xattr->list, &new_xattr->list); + if (removed_size) + *removed_size = xattr->size; } else { list_del(&xattr->list); + if (removed_size) + *removed_size = xattr->size; } goto out; } @@ -912,7 +1109,7 @@ out: spin_unlock(&xattrs->lock); if (xattr) { kfree(xattr->name); - kfree(xattr); + kvfree(xattr); } return err; |