linux-toradex.git/fs/9p/acl.c, branch v5.0

9p: acl: fix uninitialized iattr access

2018-09-07T16:51:50+00:00

iattr is passed to v9fs_vfs_setattr_dotl which does send various
values from iattr over the wire, even if it tells the server to
only look at iattr.ia_valid fields this could leak some stack data.

Link: http://lkml.kernel.org/r/1536339057-21974-2-git-send-email-asmadeus@codewreck.org
Addresses-Coverity-ID: 1195601 ("Uninitalized scalar variable")
Signed-off-by: Dominique Martinet

9p: fix a potential acl leak

2017-02-23T00:41:27+00:00

posix_acl_update_mode() could possibly clear 'acl', if so we leak the
memory pointed by 'acl'.  Save this pointer before calling
posix_acl_update_mode() and release the memory if 'acl' really gets
cleared.

Link: http://lkml.kernel.org/r/1486678332-2430-1-git-send-email-xiyou.wangcong@gmail.com
Signed-off-by: Cong Wang 
Reported-by: Mark Salyzyn 
Reviewed-by: Jan Kara 
Reviewed-by: Greg Kurz 
Cc: Eric Van Hensbergen 
Cc: Ron Minnich 
Cc: Latchesar Ionkov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

posix_acl: Clear SGID bit when setting file permissions

2016-09-22T08:55:32+00:00

When file permissions are modified via chmod(2) and the user is not in
the owning group or capable of CAP_FSETID, the setgid bit is cleared in
inode_change_ok().  Setting a POSIX ACL via setxattr(2) sets the file
permissions as well as the new ACL, but doesn't clear the setgid bit in
a similar way; this allows to bypass the check in chmod(2).  Fix that.

References: CVE-2016-7097
Reviewed-by: Christoph Hellwig 
Reviewed-by: Jeff Layton 
Signed-off-by: Jan Kara 
Signed-off-by: Andreas Gruenbacher

vfs: Verify acls are valid within superblock's s_user_ns.

2016-06-30T23:04:58+00:00

Update posix_acl_valid to verify that an acl is within a user namespace.

Update the callers of posix_acl_valid to pass in an appropriate
user namespace.  For posix_acl_xattr_set and v9fs_xattr_set_acl pass in
inode->i_sb->s_user_ns to posix_acl_valid.  For md_unpack_acl pass in
&init_user_ns as no inode or superblock is in sight.

Acked-by: Seth Forshee 
Signed-off-by: "Eric W. Biederman"

switch xattr_handler->set() to passing dentry and inode separately

2016-05-27T19:39:43+00:00

preparation for similar switch in ->setxattr() (see the next commit for
rationale).

Signed-off-by: Al Viro

xattr_handler: pass dentry and inode as separate arguments of ->get()

2016-04-11T00:48:24+00:00

... and do not assume they are already attached to each other

Signed-off-by: Al Viro

posix_acl: Inode acl caching fixes

2016-03-31T04:30:15+00:00

When get_acl() is called for an inode whose ACL is not cached yet, the
get_acl inode operation is called to fetch the ACL from the filesystem.
The inode operation is responsible for updating the cached acl with
set_cached_acl().  This is done without locking at the VFS level, so
another task can call set_cached_acl() or forget_cached_acl() before the
get_acl inode operation gets to calling set_cached_acl(), and then
get_acl's call to set_cached_acl() results in caching an outdate ACL.

Prevent this from happening by setting the cached ACL pointer to a
task-specific sentinel value before calling the get_acl inode operation.
Move the responsibility for updating the cached ACL from the get_acl
inode operations to get_acl().  There, only set the cached ACL if the
sentinel value hasn't changed.

The sentinel values are chosen to have odd values.  Likewise, the value
of ACL_NOT_CACHED is odd.  In contrast, ACL object pointers always have
an even value (ACLs are aligned in memory).  This allows to distinguish
uncached ACLs values from ACL objects.

In addition, switch from guarding inode->i_acl and inode->i_default_acl
upates by the inode->i_lock spinlock to using xchg() and cmpxchg().

Filesystems that do not want ACLs returned from their get_acl inode
operations to be cached must call forget_cached_acl() to prevent the VFS
from doing so.

(Patch written by Al Viro and Andreas Gruenbacher.)

Signed-off-by: Andreas Gruenbacher 
Signed-off-by: Al Viro

vfs: Distinguish between full xattr names and proper prefixes

2015-12-07T02:33:52+00:00

Add an additional "name" field to struct xattr_handler.  When the name
is set, the handler matches attributes with exactly that name.  When the
prefix is set instead, the handler matches attributes with the given
prefix and with a non-empty suffix.

This patch should avoid bugs like the one fixed in commit c361016a in
the future.

Signed-off-by: Andreas Gruenbacher 
Reviewed-by: James Morris 
Signed-off-by: Al Viro

posix acls: Remove duplicate xattr name definitions

2015-12-07T02:25:17+00:00

Remove POSIX_ACL_XATTR_{ACCESS,DEFAULT} and GFS2_POSIX_ACL_{ACCESS,DEFAULT}
and replace them with the definitions in .

Signed-off-by: Andreas Gruenbacher 
Reviewed-by: James Morris 
Signed-off-by: Al Viro

9p: xattr simplifications

2015-11-14T01:34:33+00:00

Now that the xattr handler is passed to the xattr handler operations, we
can use the same get and set operations for the user, trusted, and security
xattr namespaces.  In those namespaces, we can access the full attribute
name by "reattaching" the name prefix the vfs has skipped for us.  Add a
xattr_full_name helper to make this obvious in the code.

For the "system.posix_acl_access" and "system.posix_acl_default"
attributes, handler->prefix is the full attribute name; the suffix is the
empty string.

Signed-off-by: Andreas Gruenbacher 
Cc: Eric Van Hensbergen 
Cc: Ron Minnich 
Cc: Latchesar Ionkov 
Cc: v9fs-developer@lists.sourceforge.net
Signed-off-by: Al Viro