When using the per-superblock xattr handlers permission checking is
done by the generic code. hfsplus just needs to check for the magic
osx attribute not to leak into protected namespaces.
Also given that the code was obviously copied from JFS the proper
attribution was missing.
Signed-off-by: Christoph Hellwig <[email protected]>
---
fs/hfsplus/xattr.c | 87 ++--------------------------------------------------
1 file changed, 3 insertions(+), 84 deletions(-)
diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
index bf88baa..0b4a5c9 100644
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -52,82 +52,6 @@ static inline int is_known_namespace(const char *name)
return true;
}
-static int can_set_system_xattr(struct inode *inode, const char *name,
- const void *value, size_t size)
-{
-#ifdef CONFIG_HFSPLUS_FS_POSIX_ACL
- struct posix_acl *acl;
- int err;
-
- if (!inode_owner_or_capable(inode))
- return -EPERM;
-
- /*
- * POSIX_ACL_XATTR_ACCESS is tied to i_mode
- */
- if (strcmp(name, POSIX_ACL_XATTR_ACCESS) == 0) {
- acl = posix_acl_from_xattr(&init_user_ns, value, size);
- if (IS_ERR(acl))
- return PTR_ERR(acl);
- if (acl) {
- err = posix_acl_equiv_mode(acl, &inode->i_mode);
- posix_acl_release(acl);
- if (err < 0)
- return err;
- mark_inode_dirty(inode);
- }
- /*
- * We're changing the ACL. Get rid of the cached one
- */
- forget_cached_acl(inode, ACL_TYPE_ACCESS);
-
- return 0;
- } else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0) {
- acl = posix_acl_from_xattr(&init_user_ns, value, size);
- if (IS_ERR(acl))
- return PTR_ERR(acl);
- posix_acl_release(acl);
-
- /*
- * We're changing the default ACL. Get rid of the cached one
- */
- forget_cached_acl(inode, ACL_TYPE_DEFAULT);
-
- return 0;
- }
-#endif /* CONFIG_HFSPLUS_FS_POSIX_ACL */
- return -EOPNOTSUPP;
-}
-
-static int can_set_xattr(struct inode *inode, const char *name,
- const void *value, size_t value_len)
-{
- if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
- return can_set_system_xattr(inode, name, value, value_len);
-
- if (!strncmp(name, XATTR_MAC_OSX_PREFIX, XATTR_MAC_OSX_PREFIX_LEN)) {
- /*
- * This makes sure that we aren't trying to set an
- * attribute in a different namespace by prefixing it
- * with "osx."
- */
- if (is_known_namespace(name + XATTR_MAC_OSX_PREFIX_LEN))
- return -EOPNOTSUPP;
-
- return 0;
- }
-
- /*
- * Don't allow setting an attribute in an unknown namespace.
- */
- if (strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) &&
- strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
- strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
- return -EOPNOTSUPP;
-
- return 0;
-}
-
static void hfsplus_init_header_node(struct inode *attr_file,
u32 clump_size,
char *buf, u16 node_size)
@@ -350,10 +274,6 @@ int __hfsplus_setxattr(struct inode *inode, const char *name,
HFSPLUS_IS_RSRC(inode))
return -EOPNOTSUPP;
- err = can_set_xattr(inode, name, value, size);
- if (err)
- return err;
-
if (strncmp(name, XATTR_MAC_OSX_PREFIX,
XATTR_MAC_OSX_PREFIX_LEN) == 0)
name += XATTR_MAC_OSX_PREFIX_LEN;
@@ -841,10 +761,6 @@ int hfsplus_removexattr(struct dentry *dentry, const char *name)
if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
return -EOPNOTSUPP;
- err = can_set_xattr(inode, name, NULL, 0);
- if (err)
- return err;
-
if (strncmp(name, XATTR_MAC_OSX_PREFIX,
XATTR_MAC_OSX_PREFIX_LEN) == 0)
name += XATTR_MAC_OSX_PREFIX_LEN;
@@ -941,6 +857,9 @@ static int hfsplus_osx_setxattr(struct dentry *dentry, const char *name,
if (len > HFSPLUS_ATTR_MAX_STRLEN)
return -EOPNOTSUPP;
+ if (is_known_namespace(name))
+ return -EOPNOTSUPP;
+
strcpy(xattr_name, XATTR_MAC_OSX_PREFIX);
strcpy(xattr_name + XATTR_MAC_OSX_PREFIX_LEN, name);
--
1.7.10.4
On Dec 20, 2013, at 4:16 PM, Christoph Hellwig wrote:
> When using the per-superblock xattr handlers permission checking is
> done by the generic code. hfsplus just needs to check for the magic
> osx attribute not to leak into protected namespaces.
>
> Also given that the code was obviously copied from JFS the proper
> attribution was missing.
>
I don't think that this code changing is correct. Current modification
breaks logic. Please, see my comments below.
> Signed-off-by: Christoph Hellwig <[email protected]>
> ---
> fs/hfsplus/xattr.c | 87 ++--------------------------------------------------
> 1 file changed, 3 insertions(+), 84 deletions(-)
>
> diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
> index bf88baa..0b4a5c9 100644
> --- a/fs/hfsplus/xattr.c
> +++ b/fs/hfsplus/xattr.c
> @@ -52,82 +52,6 @@ static inline int is_known_namespace(const char *name)
> return true;
> }
>
> -static int can_set_system_xattr(struct inode *inode, const char *name,
> - const void *value, size_t size)
I agree that it makes sense to remove this code if permission checking
is done by generic code.
> -{
> -#ifdef CONFIG_HFSPLUS_FS_POSIX_ACL
> - struct posix_acl *acl;
> - int err;
> -
> - if (!inode_owner_or_capable(inode))
> - return -EPERM;
> -
> - /*
> - * POSIX_ACL_XATTR_ACCESS is tied to i_mode
> - */
> - if (strcmp(name, POSIX_ACL_XATTR_ACCESS) == 0) {
> - acl = posix_acl_from_xattr(&init_user_ns, value, size);
> - if (IS_ERR(acl))
> - return PTR_ERR(acl);
> - if (acl) {
> - err = posix_acl_equiv_mode(acl, &inode->i_mode);
> - posix_acl_release(acl);
> - if (err < 0)
> - return err;
> - mark_inode_dirty(inode);
> - }
> - /*
> - * We're changing the ACL. Get rid of the cached one
> - */
> - forget_cached_acl(inode, ACL_TYPE_ACCESS);
> -
> - return 0;
> - } else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0) {
> - acl = posix_acl_from_xattr(&init_user_ns, value, size);
> - if (IS_ERR(acl))
> - return PTR_ERR(acl);
> - posix_acl_release(acl);
> -
> - /*
> - * We're changing the default ACL. Get rid of the cached one
> - */
> - forget_cached_acl(inode, ACL_TYPE_DEFAULT);
> -
> - return 0;
> - }
> -#endif /* CONFIG_HFSPLUS_FS_POSIX_ACL */
> - return -EOPNOTSUPP;
> -}
> -
> -static int can_set_xattr(struct inode *inode, const char *name,
> - const void *value, size_t value_len)
This function works for all handlers. So, I don't think that it makes sense
to delete it.
> -{
> - if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
> - return can_set_system_xattr(inode, name, value, value_len);
> -
I agree that it needs to remove this check for XATTR_SYSTEM_PREFIX case.
> - if (!strncmp(name, XATTR_MAC_OSX_PREFIX, XATTR_MAC_OSX_PREFIX_LEN)) {
> - /*
> - * This makes sure that we aren't trying to set an
> - * attribute in a different namespace by prefixing it
> - * with "osx."
> - */
> - if (is_known_namespace(name + XATTR_MAC_OSX_PREFIX_LEN))
> - return -EOPNOTSUPP;
I think that this check is important. It forbids such combinations as "osx.system.*" or
"osx.trusted.*", for example. Because "osx.*" is virtual namespace for xattrs that
it can be under Mac OS X. If you want to set xattr from "system.*" namespace, for example,
then you need to use another handler. And such namespace should be without
addition of "osx." prefix.
> -
> - return 0;
> - }
> -
> - /*
> - * Don't allow setting an attribute in an unknown namespace.
> - */
> - if (strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) &&
> - strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
> - strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
> - return -EOPNOTSUPP;
> -
> - return 0;
> -}
> -
> static void hfsplus_init_header_node(struct inode *attr_file,
> u32 clump_size,
> char *buf, u16 node_size)
> @@ -350,10 +274,6 @@ int __hfsplus_setxattr(struct inode *inode, const char *name,
> HFSPLUS_IS_RSRC(inode))
> return -EOPNOTSUPP;
>
> - err = can_set_xattr(inode, name, value, size);
The __hfsplus_setxattr() is common method for all handlers. So, removing
this call means that we don't check validity of namespace. I don't think
that such modification is a right way.
> - if (err)
> - return err;
> -
> if (strncmp(name, XATTR_MAC_OSX_PREFIX,
> XATTR_MAC_OSX_PREFIX_LEN) == 0)
> name += XATTR_MAC_OSX_PREFIX_LEN;
> @@ -841,10 +761,6 @@ int hfsplus_removexattr(struct dentry *dentry, const char *name)
> if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
> return -EOPNOTSUPP;
>
> - err = can_set_xattr(inode, name, NULL, 0);
Ditto. Moreover, it is used namely hfsplus_removexattr() and not
__hfsplus_setxattr() for removing xattrs in hfsplus driver. So, removing
this check is not good way.
> - if (err)
> - return err;
> -
> if (strncmp(name, XATTR_MAC_OSX_PREFIX,
> XATTR_MAC_OSX_PREFIX_LEN) == 0)
> name += XATTR_MAC_OSX_PREFIX_LEN;
> @@ -941,6 +857,9 @@ static int hfsplus_osx_setxattr(struct dentry *dentry, const char *name,
> if (len > HFSPLUS_ATTR_MAX_STRLEN)
> return -EOPNOTSUPP;
>
> + if (is_known_namespace(name))
> + return -EOPNOTSUPP;
If common check in __hfsplus_setxattr() will be on the same place then
this addition doesn't make sense.
Thanks,
Vyacheslav Dubeyko.
> +
> strcpy(xattr_name, XATTR_MAC_OSX_PREFIX);
> strcpy(xattr_name + XATTR_MAC_OSX_PREFIX_LEN, name);
>
> --
> 1.7.10.4
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
_______________________________________________
xfs mailing list
[email protected]
http://oss.sgi.com/mailman/listinfo/xfs
On Sat, Dec 21, 2013 at 08:07:51PM +0300, Vyacheslav Dubeyko wrote:
> > -static int can_set_xattr(struct inode *inode, const char *name,
> > - const void *value, size_t value_len)
>
> This function works for all handlers. So, I don't think that it makes sense
> to delete it.
It "works" in a minimal sense that it won't crash or actively cause
harm. But it also is useless except for the check that we can abuse
the osx namespace to set an attribute in another namespace, which we
still do in the proper way after my patch.
> > - if (!strncmp(name, XATTR_MAC_OSX_PREFIX, XATTR_MAC_OSX_PREFIX_LEN)) {
> > - /*
> > - * This makes sure that we aren't trying to set an
> > - * attribute in a different namespace by prefixing it
> > - * with "osx."
> > - */
> > - if (is_known_namespace(name + XATTR_MAC_OSX_PREFIX_LEN))
> > - return -EOPNOTSUPP;
>
> I think that this check is important. It forbids such combinations as "osx.system.*" or
> "osx.trusted.*", for example. Because "osx.*" is virtual namespace for xattrs that
> it can be under Mac OS X. If you want to set xattr from "system.*" namespace, for example,
> then you need to use another handler. And such namespace should be without
> addition of "osx." prefix.
Right, and we keep exactly the check, just in a different place.
> The __hfsplus_setxattr() is common method for all handlers. So, removing
> this call means that we don't check validity of namespace. I don't think
> that such modification is a right way.
The generic code already checks for the validity of the namespace for
you. xattr_resolve_name in fs/xattr.c makes sure only attributes for a
namespace that the filesystem registered can be set or modified.
> > @@ -841,10 +761,6 @@ int hfsplus_removexattr(struct dentry *dentry, const char *name)
> > if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
> > return -EOPNOTSUPP;
> >
> > - err = can_set_xattr(inode, name, NULL, 0);
>
> Ditto. Moreover, it is used namely hfsplus_removexattr() and not
> __hfsplus_setxattr() for removing xattrs in hfsplus driver. So, removing
> this check is not good way.
Oh, I just noticed that hfsplus does not use the xattr handlers for
removing, while it does for getting and setting xattrs. That's a really
bad a confusing design, and we'll indeed need to fix that as well.
> > if (len > HFSPLUS_ATTR_MAX_STRLEN)
> > return -EOPNOTSUPP;
> >
> > + if (is_known_namespace(name))
> > + return -EOPNOTSUPP;
>
> If common check in __hfsplus_setxattr() will be on the same place then
> this addition doesn't make sense.
Having both does indeed not make sense, but this is the better place to
have it.
On Sun, 2013-12-22 at 11:28 -0800, Christoph Hellwig wrote:
>
> > > - if (!strncmp(name, XATTR_MAC_OSX_PREFIX, XATTR_MAC_OSX_PREFIX_LEN)) {
> > > - /*
> > > - * This makes sure that we aren't trying to set an
> > > - * attribute in a different namespace by prefixing it
> > > - * with "osx."
> > > - */
> > > - if (is_known_namespace(name + XATTR_MAC_OSX_PREFIX_LEN))
> > > - return -EOPNOTSUPP;
> >
> > I think that this check is important. It forbids such combinations as "osx.system.*" or
> > "osx.trusted.*", for example. Because "osx.*" is virtual namespace for xattrs that
> > it can be under Mac OS X. If you want to set xattr from "system.*" namespace, for example,
> > then you need to use another handler. And such namespace should be without
> > addition of "osx." prefix.
>
> Right, and we keep exactly the check, just in a different place.
>
Maybe I missed something, but I can see that this check is removed only.
Could you point out the code in your patch that it checks and forbids
such combination as "osx.security.*", "osx.trusted.*" and so on?
I can see that is_known_namespace() is called for
hfsplus_xattr_osx_handler only. But this method doesn't contain
above-mentioned check. Moreover, hfsplus_xattr_user_handler,
hfsplus_xattr_trusted_handler, hfsplus_xattr_security_handler will be
without is_know_namespace() check. What about it?
> > The __hfsplus_setxattr() is common method for all handlers. So, removing
> > this call means that we don't check validity of namespace. I don't think
> > that such modification is a right way.
>
> The generic code already checks for the validity of the namespace for
> you. xattr_resolve_name in fs/xattr.c makes sure only attributes for a
> namespace that the filesystem registered can be set or modified.
>
But generic code doesn't check such names combination that it is treated
as wrong for concrete file systems. For example, "osx.security.*" is
wrong for the case of HFS+. Because it will works
hfsplus_xattr_osx_handler instead of hfsplus_xattr_security_handler.
> > > @@ -841,10 +761,6 @@ int hfsplus_removexattr(struct dentry *dentry, const char *name)
> > > if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
> > > return -EOPNOTSUPP;
> > >
> > > - err = can_set_xattr(inode, name, NULL, 0);
> >
> > Ditto. Moreover, it is used namely hfsplus_removexattr() and not
> > __hfsplus_setxattr() for removing xattrs in hfsplus driver. So, removing
> > this check is not good way.
>
> Oh, I just noticed that hfsplus does not use the xattr handlers for
> removing, while it does for getting and setting xattrs. That's a really
> bad a confusing design, and we'll indeed need to fix that as well.
>
Why bad design? Do you mean that using .removexattr callback is bad
idea?
So, if it needs to use xattr handler only for removing then it needs to
make some refactoring of using __hfsplus_setxattr() and
hfsplus_removexattr() or merging these two functions into one. And I
think that merging is better idea.
Thanks,
Vyacheslav Dubeyko.
_______________________________________________
xfs mailing list
[email protected]
http://oss.sgi.com/mailman/listinfo/xfs
On Mon, Dec 23, 2013 at 10:40:09AM +0400, Vyacheslav Dubeyko wrote:
> Maybe I missed something, but I can see that this check is removed only.
> Could you point out the code in your patch that it checks and forbids
> such combination as "osx.security.*", "osx.trusted.*" and so on?
@@ -941,6 +857,9 @@ static int hfsplus_osx_setxattr(struct dentry
*dentry, const char *name,
if (len > HFSPLUS_ATTR_MAX_STRLEN)
return -EOPNOTSUPP;
+ if (is_known_namespace(name))
+ return -EOPNOTSUPP;
+
> I can see that is_known_namespace() is called for
> hfsplus_xattr_osx_handler only. But this method doesn't contain
> above-mentioned check. Moreover, hfsplus_xattr_user_handler,
> hfsplus_xattr_trusted_handler, hfsplus_xattr_security_handler will be
> without is_know_namespace() check. What about it?
They only allow you to set user.*, trusted.* and security.* attributs,
because the only get called for it. For osx.* attributes the osx
handler gets called, and passed the name minus the osx prefix, which
is why the above check will catch it.
> Why bad design? Do you mean that using .removexattr callback is bad
> idea?
Using the handlers for set and get and not using them for remove is a
bad design, because it uses different levels of abstraction for
related operations. I'm also increasingly of the opnion that we
should not allow the non-handler version, and that we should not permit
filesystems to create their own namespaces, but that's an unrelated
discussion.
> So, if it needs to use xattr handler only for removing then it needs to
> make some refactoring of using __hfsplus_setxattr() and
> hfsplus_removexattr() or merging these two functions into one. And I
> think that merging is better idea.
I've not done the full merge, but below is an updated patch to make
sure hfsplus uses the handlers for the remove case, and making sure
the adding/striping of the prefix for the osv handlers is more
transparent:
diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c
index 9ee6298..bdec665 100644
--- a/fs/hfsplus/dir.c
+++ b/fs/hfsplus/dir.c
@@ -529,7 +529,7 @@ const struct inode_operations hfsplus_dir_inode_operations = {
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = hfsplus_listxattr,
- .removexattr = hfsplus_removexattr,
+ .removexattr = generic_removexattr,
#ifdef CONFIG_HFSPLUS_FS_POSIX_ACL
.get_acl = hfsplus_get_posix_acl,
.set_acl = hfsplus_set_posix_acl,
diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index 2e10993..83c9166 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -390,7 +390,7 @@ static const struct inode_operations hfsplus_file_inode_operations = {
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = hfsplus_listxattr,
- .removexattr = hfsplus_removexattr,
+ .removexattr = generic_removexattr,
#ifdef CONFIG_HFSPLUS_FS_POSIX_ACL
.get_acl = hfsplus_get_posix_acl,
.set_acl = hfsplus_set_posix_acl,
diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
index bf88baa..c838b84 100644
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -11,6 +11,8 @@
#include "xattr.h"
#include "acl.h"
+static int hfsplus_removexattr(struct inode *inode, const char *name);
+
const struct xattr_handler *hfsplus_xattr_handlers[] = {
&hfsplus_xattr_osx_handler,
&hfsplus_xattr_user_handler,
@@ -52,82 +54,6 @@ static inline int is_known_namespace(const char *name)
return true;
}
-static int can_set_system_xattr(struct inode *inode, const char *name,
- const void *value, size_t size)
-{
-#ifdef CONFIG_HFSPLUS_FS_POSIX_ACL
- struct posix_acl *acl;
- int err;
-
- if (!inode_owner_or_capable(inode))
- return -EPERM;
-
- /*
- * POSIX_ACL_XATTR_ACCESS is tied to i_mode
- */
- if (strcmp(name, POSIX_ACL_XATTR_ACCESS) == 0) {
- acl = posix_acl_from_xattr(&init_user_ns, value, size);
- if (IS_ERR(acl))
- return PTR_ERR(acl);
- if (acl) {
- err = posix_acl_equiv_mode(acl, &inode->i_mode);
- posix_acl_release(acl);
- if (err < 0)
- return err;
- mark_inode_dirty(inode);
- }
- /*
- * We're changing the ACL. Get rid of the cached one
- */
- forget_cached_acl(inode, ACL_TYPE_ACCESS);
-
- return 0;
- } else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0) {
- acl = posix_acl_from_xattr(&init_user_ns, value, size);
- if (IS_ERR(acl))
- return PTR_ERR(acl);
- posix_acl_release(acl);
-
- /*
- * We're changing the default ACL. Get rid of the cached one
- */
- forget_cached_acl(inode, ACL_TYPE_DEFAULT);
-
- return 0;
- }
-#endif /* CONFIG_HFSPLUS_FS_POSIX_ACL */
- return -EOPNOTSUPP;
-}
-
-static int can_set_xattr(struct inode *inode, const char *name,
- const void *value, size_t value_len)
-{
- if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
- return can_set_system_xattr(inode, name, value, value_len);
-
- if (!strncmp(name, XATTR_MAC_OSX_PREFIX, XATTR_MAC_OSX_PREFIX_LEN)) {
- /*
- * This makes sure that we aren't trying to set an
- * attribute in a different namespace by prefixing it
- * with "osx."
- */
- if (is_known_namespace(name + XATTR_MAC_OSX_PREFIX_LEN))
- return -EOPNOTSUPP;
-
- return 0;
- }
-
- /*
- * Don't allow setting an attribute in an unknown namespace.
- */
- if (strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) &&
- strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
- strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
- return -EOPNOTSUPP;
-
- return 0;
-}
-
static void hfsplus_init_header_node(struct inode *attr_file,
u32 clump_size,
char *buf, u16 node_size)
@@ -350,18 +276,8 @@ int __hfsplus_setxattr(struct inode *inode, const char *name,
HFSPLUS_IS_RSRC(inode))
return -EOPNOTSUPP;
- err = can_set_xattr(inode, name, value, size);
- if (err)
- return err;
-
- if (strncmp(name, XATTR_MAC_OSX_PREFIX,
- XATTR_MAC_OSX_PREFIX_LEN) == 0)
- name += XATTR_MAC_OSX_PREFIX_LEN;
-
- if (value == NULL) {
- value = "";
- size = 0;
- }
+ if (value == NULL)
+ return hfsplus_removexattr(inode, name);
err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
if (err) {
@@ -577,18 +493,6 @@ ssize_t __hfsplus_getxattr(struct inode *inode, const char *name,
HFSPLUS_IS_RSRC(inode))
return -EOPNOTSUPP;
- if (strncmp(name, XATTR_MAC_OSX_PREFIX,
- XATTR_MAC_OSX_PREFIX_LEN) == 0) {
- /* skip "osx." prefix */
- name += XATTR_MAC_OSX_PREFIX_LEN;
- /*
- * Don't allow retrieving properly prefixed attributes
- * by prepending them with "osx."
- */
- if (is_known_namespace(name))
- return -EOPNOTSUPP;
- }
-
if (!strcmp_xattr_finder_info(name))
return hfsplus_getxattr_finder_info(inode, value, size);
@@ -823,32 +727,18 @@ end_listxattr:
return res;
}
-int hfsplus_removexattr(struct dentry *dentry, const char *name)
+static int hfsplus_removexattr(struct inode *inode, const char *name)
{
int err = 0;
- struct inode *inode = dentry->d_inode;
struct hfs_find_data cat_fd;
u16 flags;
u16 cat_entry_type;
int is_xattr_acl_deleted = 0;
int is_all_xattrs_deleted = 0;
- if ((!S_ISREG(inode->i_mode) &&
- !S_ISDIR(inode->i_mode)) ||
- HFSPLUS_IS_RSRC(inode))
- return -EOPNOTSUPP;
-
if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
return -EOPNOTSUPP;
- err = can_set_xattr(inode, name, NULL, 0);
- if (err)
- return err;
-
- if (strncmp(name, XATTR_MAC_OSX_PREFIX,
- XATTR_MAC_OSX_PREFIX_LEN) == 0)
- name += XATTR_MAC_OSX_PREFIX_LEN;
-
if (!strcmp_xattr_finder_info(name))
return -EOPNOTSUPP;
@@ -922,8 +812,12 @@ static int hfsplus_osx_getxattr(struct dentry *dentry, const char *name,
if (len > HFSPLUS_ATTR_MAX_STRLEN)
return -EOPNOTSUPP;
- strcpy(xattr_name, XATTR_MAC_OSX_PREFIX);
- strcpy(xattr_name + XATTR_MAC_OSX_PREFIX_LEN, name);
+ /*
+ * Don't allow retrieving properly prefixed attributes
+ * by prepending them with "osx."
+ */
+ if (is_known_namespace(name))
+ return -EOPNOTSUPP;
return hfsplus_getxattr(dentry, xattr_name, buffer, size);
}
@@ -941,8 +835,12 @@ static int hfsplus_osx_setxattr(struct dentry *dentry, const char *name,
if (len > HFSPLUS_ATTR_MAX_STRLEN)
return -EOPNOTSUPP;
- strcpy(xattr_name, XATTR_MAC_OSX_PREFIX);
- strcpy(xattr_name + XATTR_MAC_OSX_PREFIX_LEN, name);
+ /*
+ * Don't allow setting properly prefixed attributes
+ * by prepending them with "osx."
+ */
+ if (is_known_namespace(name))
+ return -EOPNOTSUPP;
return hfsplus_setxattr(dentry, xattr_name, buffer, size, flags);
}
diff --git a/fs/hfsplus/xattr.h b/fs/hfsplus/xattr.h
index 9e21449..288530c 100644
--- a/fs/hfsplus/xattr.h
+++ b/fs/hfsplus/xattr.h
@@ -40,8 +40,6 @@ static inline ssize_t hfsplus_getxattr(struct dentry *dentry,
ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size);
-int hfsplus_removexattr(struct dentry *dentry, const char *name);
-
int hfsplus_init_security(struct inode *inode, struct inode *dir,
const struct qstr *qstr);
On Mon, 2013-12-23 at 06:37 -0800, Christoph Hellwig wrote:
> On Mon, Dec 23, 2013 at 10:40:09AM +0400, Vyacheslav Dubeyko wrote:
> > Maybe I missed something, but I can see that this check is removed only.
> > Could you point out the code in your patch that it checks and forbids
> > such combination as "osx.security.*", "osx.trusted.*" and so on?
>
> @@ -941,6 +857,9 @@ static int hfsplus_osx_setxattr(struct dentry
> *dentry, const char *name,
> if (len > HFSPLUS_ATTR_MAX_STRLEN)
> return -EOPNOTSUPP;
>
> + if (is_known_namespace(name))
> + return -EOPNOTSUPP;
> +
>
Yes, now I've realized your approach. You are right. It's my
misunderstanding. So, comments are really necessary for describing the
goal of this check. Thank you for adding it in the last version of
reworked patch.
>
> > So, if it needs to use xattr handler only for removing then it needs to
> > make some refactoring of using __hfsplus_setxattr() and
> > hfsplus_removexattr() or merging these two functions into one. And I
> > think that merging is better idea.
>
> I've not done the full merge, but below is an updated patch to make
> sure hfsplus uses the handlers for the remove case, and making sure
> the adding/striping of the prefix for the osv handlers is more
> transparent:
>
As far as I can judge, changing from hfsplus_removexattr() to
generic_removexattr() is made correctly.
> diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c
> index 9ee6298..bdec665 100644
> --- a/fs/hfsplus/dir.c
> +++ b/fs/hfsplus/dir.c
> @@ -529,7 +529,7 @@ const struct inode_operations hfsplus_dir_inode_operations = {
> .setxattr = generic_setxattr,
> .getxattr = generic_getxattr,
> .listxattr = hfsplus_listxattr,
> - .removexattr = hfsplus_removexattr,
> + .removexattr = generic_removexattr,
> #ifdef CONFIG_HFSPLUS_FS_POSIX_ACL
> .get_acl = hfsplus_get_posix_acl,
> .set_acl = hfsplus_set_posix_acl,
> diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
> index 2e10993..83c9166 100644
> --- a/fs/hfsplus/inode.c
> +++ b/fs/hfsplus/inode.c
> @@ -390,7 +390,7 @@ static const struct inode_operations hfsplus_file_inode_operations = {
> .setxattr = generic_setxattr,
> .getxattr = generic_getxattr,
> .listxattr = hfsplus_listxattr,
> - .removexattr = hfsplus_removexattr,
> + .removexattr = generic_removexattr,
> #ifdef CONFIG_HFSPLUS_FS_POSIX_ACL
> .get_acl = hfsplus_get_posix_acl,
> .set_acl = hfsplus_set_posix_acl,
> diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
> index bf88baa..c838b84 100644
> --- a/fs/hfsplus/xattr.c
> +++ b/fs/hfsplus/xattr.c
> @@ -11,6 +11,8 @@
> #include "xattr.h"
> #include "acl.h"
>
> +static int hfsplus_removexattr(struct inode *inode, const char *name);
> +
> const struct xattr_handler *hfsplus_xattr_handlers[] = {
> &hfsplus_xattr_osx_handler,
> &hfsplus_xattr_user_handler,
> @@ -52,82 +54,6 @@ static inline int is_known_namespace(const char *name)
> return true;
> }
>
> -static int can_set_system_xattr(struct inode *inode, const char *name,
> - const void *value, size_t size)
> -{
> -#ifdef CONFIG_HFSPLUS_FS_POSIX_ACL
> - struct posix_acl *acl;
> - int err;
> -
> - if (!inode_owner_or_capable(inode))
> - return -EPERM;
> -
> - /*
> - * POSIX_ACL_XATTR_ACCESS is tied to i_mode
> - */
> - if (strcmp(name, POSIX_ACL_XATTR_ACCESS) == 0) {
> - acl = posix_acl_from_xattr(&init_user_ns, value, size);
> - if (IS_ERR(acl))
> - return PTR_ERR(acl);
> - if (acl) {
> - err = posix_acl_equiv_mode(acl, &inode->i_mode);
> - posix_acl_release(acl);
> - if (err < 0)
> - return err;
> - mark_inode_dirty(inode);
> - }
> - /*
> - * We're changing the ACL. Get rid of the cached one
> - */
> - forget_cached_acl(inode, ACL_TYPE_ACCESS);
> -
> - return 0;
> - } else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0) {
> - acl = posix_acl_from_xattr(&init_user_ns, value, size);
> - if (IS_ERR(acl))
> - return PTR_ERR(acl);
> - posix_acl_release(acl);
> -
> - /*
> - * We're changing the default ACL. Get rid of the cached one
> - */
> - forget_cached_acl(inode, ACL_TYPE_DEFAULT);
> -
> - return 0;
> - }
> -#endif /* CONFIG_HFSPLUS_FS_POSIX_ACL */
> - return -EOPNOTSUPP;
> -}
> -
> -static int can_set_xattr(struct inode *inode, const char *name,
> - const void *value, size_t value_len)
> -{
> - if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
> - return can_set_system_xattr(inode, name, value, value_len);
> -
> - if (!strncmp(name, XATTR_MAC_OSX_PREFIX, XATTR_MAC_OSX_PREFIX_LEN)) {
> - /*
> - * This makes sure that we aren't trying to set an
> - * attribute in a different namespace by prefixing it
> - * with "osx."
> - */
> - if (is_known_namespace(name + XATTR_MAC_OSX_PREFIX_LEN))
> - return -EOPNOTSUPP;
> -
> - return 0;
> - }
> -
> - /*
> - * Don't allow setting an attribute in an unknown namespace.
> - */
> - if (strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) &&
> - strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
> - strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
> - return -EOPNOTSUPP;
> -
> - return 0;
> -}
> -
> static void hfsplus_init_header_node(struct inode *attr_file,
> u32 clump_size,
> char *buf, u16 node_size)
> @@ -350,18 +276,8 @@ int __hfsplus_setxattr(struct inode *inode, const char *name,
> HFSPLUS_IS_RSRC(inode))
> return -EOPNOTSUPP;
>
> - err = can_set_xattr(inode, name, value, size);
> - if (err)
> - return err;
> -
> - if (strncmp(name, XATTR_MAC_OSX_PREFIX,
> - XATTR_MAC_OSX_PREFIX_LEN) == 0)
> - name += XATTR_MAC_OSX_PREFIX_LEN;
Removing this skipping of virtual "osx." prefix means that you save it
on volume. But such action means volume corruption really. Because HFS+
volume hasn't such prefixes for xattrs in AttributesFile. Usually,
special xattrs has prefix "com.apple.*" but others haven't any prefix
and can be named as you want. So, I think that it is not correct
modification.
> -
> - if (value == NULL) {
> - value = "";
> - size = 0;
> - }
> + if (value == NULL)
> + return hfsplus_removexattr(inode, name);
>
> err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
> if (err) {
> @@ -577,18 +493,6 @@ ssize_t __hfsplus_getxattr(struct inode *inode, const char *name,
> HFSPLUS_IS_RSRC(inode))
> return -EOPNOTSUPP;
>
> - if (strncmp(name, XATTR_MAC_OSX_PREFIX,
> - XATTR_MAC_OSX_PREFIX_LEN) == 0) {
> - /* skip "osx." prefix */
> - name += XATTR_MAC_OSX_PREFIX_LEN;
Ditto. This skipping is made because virtual prefix was added by user or
on listxattr phase. But we should use for searching on a volume the name
without "osx." prefix. Otherwise, how do you get
"com.apple.system.Security" xattr from volume, for example? You will
search "osx.com.apple.system.Security" that doesn't exist on HFS+
volume.
Thanks,
Vyacheslav Dubeyko.