The patch titled
tmpfs-implement-xattr-support-for-the-entire-security-namespace-update
has been removed from the -mm tree. Its filename was
tmpfs-implement-xattr-support-for-the-entire-security-namespace-update.patch
This patch was dropped because an updated version will be merged
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: tmpfs-implement-xattr-support-for-the-entire-security-namespace-update
From: Miklos Szeredi <miklos@xxxxxxxxxx>
new config option, suport trusted.*, support symlinks]
Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
Acked-by: Serge Hallyn <serge.hallyn@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/Kconfig | 22 ++-
mm/shmem.c | 298 +++++++++++++++++++++++++++++++++++----------------
2 files changed, 224 insertions(+), 96 deletions(-)
diff -puN fs/Kconfig~tmpfs-implement-xattr-support-for-the-entire-security-namespace-update fs/Kconfig
--- a/fs/Kconfig~tmpfs-implement-xattr-support-for-the-entire-security-namespace-update
+++ a/fs/Kconfig
@@ -121,9 +121,25 @@ config TMPFS
See <file:Documentation/filesystems/tmpfs.txt> for details.
+config TMPFS_XATTR
+ bool "Tmpfs extended attributes"
+ depends on TMPFS
+ default y
+ help
+ Extended attributes are name:value pairs associated with inodes by
+ the kernel or by users (see the attr(5) manual page, or visit
+ <http://acl.bestbits.at/> for details).
+
+ Currently this enables support for the trusted.* and
+ security.* namespaces.
+
+ If unsure, say N.
+
+ You need this for POSIX ACL support on tmpfs.
+
config TMPFS_POSIX_ACL
bool "Tmpfs POSIX Access Control Lists"
- depends on TMPFS
+ depends on TMPFS_XATTR
select GENERIC_ACL
help
POSIX Access Control Lists (ACLs) support permissions for users and
@@ -132,10 +148,6 @@ config TMPFS_POSIX_ACL
To learn more about Access Control Lists, visit the POSIX ACLs for
Linux website <http://acl.bestbits.at/>.
- Enablings this option will also enable support for the entire
- security.* xattr namespace. This is to make up for support lost
- from the VFS/LSM when a filesystem has any xattr handler.
-
If you don't know what Access Control Lists are, say N.
config HUGETLBFS
diff -puN mm/shmem.c~tmpfs-implement-xattr-support-for-the-entire-security-namespace-update mm/shmem.c
--- a/mm/shmem.c~tmpfs-implement-xattr-support-for-the-entire-security-namespace-update
+++ a/mm/shmem.c
@@ -101,7 +101,7 @@ static struct vfsmount *shm_mnt;
struct shmem_xattr {
struct list_head list; /* anchored by shmem_inode_info->xattr_list */
- char *name; /* xattr suffix */
+ char *name; /* xattr name */
size_t size;
char value[0];
};
@@ -2081,18 +2081,7 @@ static void shmem_put_link(struct dentry
}
}
-static const struct inode_operations shmem_symlink_inline_operations = {
- .readlink = generic_readlink,
- .follow_link = shmem_follow_link_inline,
-};
-
-static const struct inode_operations shmem_symlink_inode_operations = {
- .readlink = generic_readlink,
- .follow_link = shmem_follow_link,
- .put_link = shmem_put_link,
-};
-
-#ifdef CONFIG_TMPFS_POSIX_ACL
+#ifdef CONFIG_TMPFS_XATTR
/*
* Superblocks without xattr inode operations may get some security.* xattr
* support from the LSM "for free". As soon as we have any other xattrs
@@ -2100,39 +2089,8 @@ static const struct inode_operations shm
* filesystem level, though.
*/
-static size_t shmem_xattr_security_list(struct dentry *dentry, char *list,
- size_t list_len, const char *name,
- size_t name_len, int handler_flags)
-{
- struct shmem_xattr *xattr;
- struct shmem_inode_info *info;
- size_t used = 0;
-
- info = SHMEM_I(dentry->d_inode);
-
- spin_lock(&dentry->d_inode->i_lock);
- list_for_each_entry(xattr, &info->xattr_list, list) {
- used += XATTR_SECURITY_PREFIX_LEN;
- used += strlen(xattr->name) + 1;
-
- if (list) {
- if (list_len < used) {
- used = -ERANGE;
- break;
- }
- strncpy(list, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN);
- list += XATTR_SECURITY_PREFIX_LEN;
- strncpy(list, xattr->name, strlen(xattr->name) + 1);
- list += strlen(xattr->name) + 1;
- }
- }
- spin_unlock(&dentry->d_inode->i_lock);
-
- return used;
-}
-
-static int shmem_xattr_security_get(struct dentry *dentry, const char *name,
- void *buffer, size_t size, int handler_flags)
+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;
@@ -2158,46 +2116,58 @@ static int shmem_xattr_security_get(stru
return ret;
}
-/*
- * We only handle security.* but we could potentially store the prefix
- * as well as the suffix in struct shmem_xattr and support *.*
- */
-static int shmem_xattr_security_set(struct dentry *dentry, const char *name,
- const void *value, size_t size, int flags, int handler_flags)
+static int shmem_xattr_set(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags)
{
struct inode *inode = dentry->d_inode;
struct shmem_inode_info *info = SHMEM_I(inode);
struct shmem_xattr *xattr;
- struct shmem_xattr *new_xattr;
+ struct shmem_xattr *new_xattr = NULL;
size_t len;
+ int err = 0;
- /* wrap around? */
- len = sizeof(*new_xattr) + size;
- if (len <= sizeof(*new_xattr))
- return -ENOMEM;
-
- new_xattr = kmalloc(len, GFP_NOFS);
- if (!new_xattr)
- return -ENOMEM;
+ /* value == NULL means remove */
+ if (value) {
+ /* wrap around? */
+ len = sizeof(*new_xattr) + size;
+ if (len <= sizeof(*new_xattr))
+ return -ENOMEM;
+
+ new_xattr = kmalloc(len, GFP_NOFS);
+ if (!new_xattr)
+ return -ENOMEM;
+
+ new_xattr->name = kstrdup(name, GFP_NOFS);
+ if (!new_xattr->name) {
+ kfree(new_xattr);
+ return -ENOMEM;
+ }
- new_xattr->name = kstrdup(name, GFP_NOFS);
- if (!new_xattr->name) {
- kfree(new_xattr);
- return -ENOMEM;
+ new_xattr->size = size;
+ memcpy(new_xattr->value, value, size);
}
- new_xattr->size = size;
- memcpy(new_xattr->value, value, size);
-
spin_lock(&inode->i_lock);
list_for_each_entry(xattr, &info->xattr_list, list) {
if (!strcmp(name, xattr->name)) {
- list_replace(&xattr->list, &new_xattr->list);
+ 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;
}
}
- list_add(&new_xattr->list, &info->xattr_list);
- xattr = NULL;
+ if (flags & XATTR_REPLACE) {
+ xattr = new_xattr;
+ err = -ENODATA;
+ } else {
+ list_add(&new_xattr->list, &info->xattr_list);
+ xattr = NULL;
+ }
out:
spin_unlock(&inode->i_lock);
if (xattr)
@@ -2206,19 +2176,134 @@ out:
return 0;
}
-static const struct xattr_handler shmem_xattr_security_handler = {
- .prefix = XATTR_SECURITY_PREFIX,
- .list = shmem_xattr_security_list,
- .get = shmem_xattr_security_get,
- .set = shmem_xattr_security_set,
-};
static const struct xattr_handler *shmem_xattr_handlers[] = {
+#ifdef CONFIG_TMPFS_POSIX_ACL
&generic_acl_access_handler,
&generic_acl_default_handler,
- &shmem_xattr_security_handler,
+#endif
NULL
};
+
+static int shmem_xattr_validate(const char *name)
+{
+ struct { const char *prefix; size_t len; } arr[] = {
+ { XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN },
+ { XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN }
+ };
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(arr); i++) {
+ size_t preflen = arr[i].len;
+ if (strncmp(name, arr[i].prefix, preflen) == 0) {
+ if (!name[preflen])
+ return -EINVAL;
+ return 0;
+ }
+ }
+ return -EOPNOTSUPP;
+}
+
+static ssize_t shmem_getxattr(struct dentry *dentry, const char *name,
+ void *buffer, size_t size)
+{
+ int err;
+
+ /*
+ * If this is a request for a synthetic attribute in the system.*
+ * namespace use the generic infrastructure to resolve a handler
+ * for it via sb->s_xattr.
+ */
+ if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+ return generic_getxattr(dentry, name, buffer, size);
+
+ err = shmem_xattr_validate(name);
+ if (err)
+ return err;
+
+ return shmem_xattr_get(dentry, name, buffer, size);
+}
+
+static int shmem_setxattr(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags)
+{
+ int err;
+
+ /*
+ * If this is a request for a synthetic attribute in the system.*
+ * namespace use the generic infrastructure to resolve a handler
+ * for it via sb->s_xattr.
+ */
+ if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+ return generic_setxattr(dentry, name, value, size, flags);
+
+ err = shmem_xattr_validate(name);
+ if (err)
+ return err;
+
+ if (size == 0)
+ value = ""; /* empty EA, do not remove */
+
+ return shmem_xattr_set(dentry, name, value, size, flags);
+
+}
+
+static int shmem_removexattr(struct dentry *dentry, const char *name)
+{
+ int err;
+
+ /*
+ * If this is a request for a synthetic attribute in the system.*
+ * namespace use the generic infrastructure to resolve a handler
+ * for it via sb->s_xattr.
+ */
+ if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+ return generic_removexattr(dentry, name);
+
+ err = shmem_xattr_validate(name);
+ if (err)
+ return err;
+
+ return shmem_xattr_set(dentry, name, NULL, 0, XATTR_REPLACE);
+}
+
+static bool xattr_is_trusted(const char *name)
+{
+ return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
+}
+
+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(&dentry->d_inode->i_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(&dentry->d_inode->i_lock);
+
+ return used;
+}
#endif
static struct dentry *shmem_get_parent(struct dentry *child)
@@ -2499,8 +2584,10 @@ int shmem_fill_super(struct super_block
sb->s_magic = TMPFS_MAGIC;
sb->s_op = &shmem_ops;
sb->s_time_gran = 1;
-#ifdef CONFIG_TMPFS_POSIX_ACL
+#ifdef CONFIG_TMPFS_XATTR
sb->s_xattr = shmem_xattr_handlers;
+#endif
+#ifdef CONFIG_TMPFS_POSIX_ACL
sb->s_flags |= MS_POSIXACL;
#endif
@@ -2598,16 +2685,41 @@ static const struct file_operations shme
static const struct inode_operations shmem_inode_operations = {
.setattr = shmem_notify_change,
.truncate_range = shmem_truncate_range,
+#ifdef CONFIG_TMPFS_XATTR
+ .setxattr = shmem_setxattr,
+ .getxattr = shmem_getxattr,
+ .listxattr = shmem_listxattr,
+ .removexattr = shmem_removexattr,
+#endif
#ifdef CONFIG_TMPFS_POSIX_ACL
- .setxattr = generic_setxattr,
- .getxattr = generic_getxattr,
- .listxattr = generic_listxattr,
- .removexattr = generic_removexattr,
.check_acl = generic_check_acl,
#endif
};
+static const struct inode_operations shmem_symlink_inline_operations = {
+ .readlink = generic_readlink,
+ .follow_link = shmem_follow_link_inline,
+#ifdef CONFIG_TMPFS_XATTR
+ .setxattr = shmem_setxattr,
+ .getxattr = shmem_getxattr,
+ .listxattr = shmem_listxattr,
+ .removexattr = shmem_removexattr,
+#endif
+};
+
+static const struct inode_operations shmem_symlink_inode_operations = {
+ .readlink = generic_readlink,
+ .follow_link = shmem_follow_link,
+ .put_link = shmem_put_link,
+#ifdef CONFIG_TMPFS_XATTR
+ .setxattr = shmem_setxattr,
+ .getxattr = shmem_getxattr,
+ .listxattr = shmem_listxattr,
+ .removexattr = shmem_removexattr,
+#endif
+};
+
static const struct inode_operations shmem_dir_inode_operations = {
#ifdef CONFIG_TMPFS
.create = shmem_create,
@@ -2620,23 +2732,27 @@ static const struct inode_operations shm
.mknod = shmem_mknod,
.rename = shmem_rename,
#endif
+#ifdef CONFIG_TMPFS_XATTR
+ .setxattr = shmem_setxattr,
+ .getxattr = shmem_getxattr,
+ .listxattr = shmem_listxattr,
+ .removexattr = shmem_removexattr,
+#endif
#ifdef CONFIG_TMPFS_POSIX_ACL
.setattr = shmem_notify_change,
- .setxattr = generic_setxattr,
- .getxattr = generic_getxattr,
- .listxattr = generic_listxattr,
- .removexattr = generic_removexattr,
.check_acl = generic_check_acl,
#endif
};
static const struct inode_operations shmem_special_inode_operations = {
+#ifdef CONFIG_TMPFS_XATTR
+ .setxattr = shmem_setxattr,
+ .getxattr = shmem_getxattr,
+ .listxattr = shmem_listxattr,
+ .removexattr = shmem_removexattr,
+#endif
#ifdef CONFIG_TMPFS_POSIX_ACL
.setattr = shmem_notify_change,
- .setxattr = generic_setxattr,
- .getxattr = generic_getxattr,
- .listxattr = generic_listxattr,
- .removexattr = generic_removexattr,
.check_acl = generic_check_acl,
#endif
};
_
Patches currently in -mm which might be from miklos@xxxxxxxxxx are
tmpfs-implement-xattr-support-for-the-entire-security-namespace-update-fix.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
