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kernel: backport and enable tmpfs xattr support for 2.6.39

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SVN-Revision: 27691
This commit is contained in:
Felix Fietkau
2011-07-19 09:00:55 +00:00
parent 9c606eb4c5
commit fee32761f3
3 changed files with 480 additions and 2 deletions
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1
target/linux/generic/config-2.6.39
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@@ -2631,6 +2631,7 @@ CONFIG_TINY_RCU=y
# CONFIG_TLAN is not set
# CONFIG_TMD_HERMES is not set
CONFIG_TMPFS=y
CONFIG_TMPFS_XATTR=y
# CONFIG_TMPFS_POSIX_ACL is not set
# CONFIG_TOUCHSCREEN_AD7877 is not set
# CONFIG_TOUCHSCREEN_AD7879 is not set

477
target/linux/generic/patches-2.6.39/040-backport_tmpfs_xattr.patch Normal file
View File

@@ -0,0 +1,477 @@
--- a/fs/Kconfig
+++ b/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 n
+ 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
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -9,6 +9,8 @@
#define SHMEM_NR_DIRECT 16
+#define SHMEM_SYMLINK_INLINE_LEN (SHMEM_NR_DIRECT * sizeof(swp_entry_t))
+
struct shmem_inode_info {
spinlock_t lock;
unsigned long flags;
@@ -17,8 +19,12 @@ struct shmem_inode_info {
unsigned long next_index; /* highest alloced index + 1 */
struct shared_policy policy; /* NUMA memory alloc policy */
struct page *i_indirect; /* top indirect blocks page */
- swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* first blocks */
+ union {
+ swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* first blocks */
+ char inline_symlink[SHMEM_SYMLINK_INLINE_LEN];
+ };
struct list_head swaplist; /* chain of maybes on swap */
+ struct list_head xattr_list; /* list of shmem_xattr */
struct inode vfs_inode;
};
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -99,6 +99,13 @@ static struct vfsmount *shm_mnt;
/* Pretend that each entry is of this size in directory's i_size */
#define BOGO_DIRENT_SIZE 20
+struct shmem_xattr {
+ struct list_head list; /* anchored by shmem_inode_info->xattr_list */
+ char *name; /* xattr name */
+ size_t size;
+ char value[0];
+};
+
/* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
enum sgp_type {
SGP_READ, /* don't exceed i_size, don't allocate page */
@@ -822,6 +829,7 @@ static int shmem_notify_change(struct de
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) {
truncate_inode_pages(inode->i_mapping, 0);
@@ -834,6 +842,11 @@ static void shmem_evict_inode(struct ino
mutex_unlock(&shmem_swaplist_mutex);
}
}
+
+ list_for_each_entry_safe(xattr, nxattr, &info->xattr_list, list) {
+ kfree(xattr->name);
+ kfree(xattr);
+ }
BUG_ON(inode->i_blocks);
shmem_free_inode(inode->i_sb);
end_writeback(inode);
@@ -1615,6 +1628,7 @@ static struct inode *shmem_get_inode(str
spin_lock_init(&info->lock);
info->flags = flags & VM_NORESERVE;
INIT_LIST_HEAD(&info->swaplist);
+ INIT_LIST_HEAD(&info->xattr_list);
cache_no_acl(inode);
switch (mode & S_IFMT) {
@@ -2014,9 +2028,9 @@ static int shmem_symlink(struct inode *d
info = SHMEM_I(inode);
inode->i_size = len-1;
- if (len <= (char *)inode - (char *)info) {
+ if (len <= SHMEM_SYMLINK_INLINE_LEN) {
/* do it inline */
- memcpy(info, symname, len);
+ memcpy(info->inline_symlink, symname, len);
inode->i_op = &shmem_symlink_inline_operations;
} else {
error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL);
@@ -2042,7 +2056,7 @@ static int shmem_symlink(struct inode *d
static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
{
- nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode));
+ nd_set_link(nd, SHMEM_I(dentry->d_inode)->inline_symlink);
return NULL;
}
@@ -2066,63 +2080,253 @@ 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 will get security.* xattr
- * support from the VFS "for free". As soon as we have any other xattrs
+ * Superblocks without xattr inode operations may get some security.* xattr
+ * support from the LSM "for free". As soon as we have any other xattrs
* like ACLs, we also need to implement the security.* handlers at
* 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)
+static int shmem_xattr_get(struct dentry *dentry, const char *name,
+ void *buffer, size_t size)
{
- return security_inode_listsecurity(dentry->d_inode, list, list_len);
-}
+ struct shmem_inode_info *info;
+ struct shmem_xattr *xattr;
+ int ret = -ENODATA;
-static int shmem_xattr_security_get(struct dentry *dentry, const char *name,
- void *buffer, size_t size, int handler_flags)
-{
- if (strcmp(name, "") == 0)
- return -EINVAL;
- return xattr_getsecurity(dentry->d_inode, name, buffer, size);
+ 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_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)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
- return security_inode_setsecurity(dentry->d_inode, name, value,
- size, flags);
+ struct inode *inode = dentry->d_inode;
+ struct shmem_inode_info *info = SHMEM_I(inode);
+ struct shmem_xattr *xattr;
+ struct shmem_xattr *new_xattr = NULL;
+ size_t len;
+ int err = 0;
+
+ /* 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_KERNEL);
+ if (!new_xattr)
+ return -ENOMEM;
+
+ new_xattr->name = kstrdup(name, GFP_KERNEL);
+ if (!new_xattr->name) {
+ kfree(new_xattr);
+ return -ENOMEM;
+ }
+
+ new_xattr->size = size;
+ memcpy(new_xattr->value, value, size);
+ }
+
+ 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_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(&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;
+}
+#endif /* CONFIG_TMPFS_XATTR */
+
+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 struct dentry *shmem_get_parent(struct dentry *child)
{
@@ -2402,8 +2606,10 @@ 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
@@ -2501,11 +2707,13 @@ 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
@@ -2523,23 +2731,27 @@ 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
};

4
target/linux/generic/patches-2.6.39/950-vm_exports.patch
View File

@@ -1,6 +1,6 @@
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2731,6 +2731,16 @@ out:
@@ -2943,6 +2943,16 @@ out:
/* common code */
@@ -17,7 +17,7 @@
/**
* shmem_file_setup - get an unlinked file living in tmpfs
* @name: name for dentry (to be seen in /proc/<pid>/maps
@@ -2808,10 +2818,7 @@ int shmem_zero_setup(struct vm_area_stru
@@ -3020,10 +3030,7 @@ int shmem_zero_setup(struct vm_area_stru
if (IS_ERR(file))
return PTR_ERR(file);