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11 commits

Author SHA1 Message Date
Jann Horn
378c6520e7 fs/coredump: prevent fsuid=0 dumps into user-controlled directories
This commit fixes the following security hole affecting systems where
all of the following conditions are fulfilled:

 - The fs.suid_dumpable sysctl is set to 2.
 - The kernel.core_pattern sysctl's value starts with "/". (Systems
   where kernel.core_pattern starts with "|/" are not affected.)
 - Unprivileged user namespace creation is permitted. (This is
   true on Linux >=3.8, but some distributions disallow it by
   default using a distro patch.)

Under these conditions, if a program executes under secure exec rules,
causing it to run with the SUID_DUMP_ROOT flag, then unshares its user
namespace, changes its root directory and crashes, the coredump will be
written using fsuid=0 and a path derived from kernel.core_pattern - but
this path is interpreted relative to the root directory of the process,
allowing the attacker to control where a coredump will be written with
root privileges.

To fix the security issue, always interpret core_pattern for dumps that
are written under SUID_DUMP_ROOT relative to the root directory of init.

Signed-off-by: Jann Horn <jann@thejh.net>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22 15:36:02 -07:00
Sasha Levin
161f873b89 vfs: read file_handle only once in handle_to_path
We used to read file_handle twice.  Once to get the amount of extra
bytes, and once to fetch the entire structure.

This may be problematic since we do size verifications only after the
first read, so if the number of extra bytes changes in userspace between
the first and second calls, we'll have an incoherent view of
file_handle.

Instead, read the constant size once, and copy that over to the final
structure without having to re-read it again.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-02 10:29:07 -07:00
Linus Torvalds
982197277c Merge branch 'for-3.8' of git://linux-nfs.org/~bfields/linux
Pull nfsd update from Bruce Fields:
 "Included this time:

   - more nfsd containerization work from Stanislav Kinsbursky: we're
     not quite there yet, but should be by 3.9.

   - NFSv4.1 progress: implementation of basic backchannel security
     negotiation and the mandatory BACKCHANNEL_CTL operation.  See

       http://wiki.linux-nfs.org/wiki/index.php/Server_4.0_and_4.1_issues

     for remaining TODO's

   - Fixes for some bugs that could be triggered by unusual compounds.
     Our xdr code wasn't designed with v4 compounds in mind, and it
     shows.  A more thorough rewrite is still a todo.

   - If you've ever seen "RPC: multiple fragments per record not
     supported" logged while using some sort of odd userland NFS client,
     that should now be fixed.

   - Further work from Jeff Layton on our mechanism for storing
     information about NFSv4 clients across reboots.

   - Further work from Bryan Schumaker on his fault-injection mechanism
     (which allows us to discard selective NFSv4 state, to excercise
     rarely-taken recovery code paths in the client.)

   - The usual mix of miscellaneous bugs and cleanup.

  Thanks to everyone who tested or contributed this cycle."

* 'for-3.8' of git://linux-nfs.org/~bfields/linux: (111 commits)
  nfsd4: don't leave freed stateid hashed
  nfsd4: free_stateid can use the current stateid
  nfsd4: cleanup: replace rq_resused count by rq_next_page pointer
  nfsd: warn on odd reply state in nfsd_vfs_read
  nfsd4: fix oops on unusual readlike compound
  nfsd4: disable zero-copy on non-final read ops
  svcrpc: fix some printks
  NFSD: Correct the size calculation in fault_inject_write
  NFSD: Pass correct buffer size to rpc_ntop
  nfsd: pass proper net to nfsd_destroy() from NFSd kthreads
  nfsd: simplify service shutdown
  nfsd: replace boolean nfsd_up flag by users counter
  nfsd: simplify NFSv4 state init and shutdown
  nfsd: introduce helpers for generic resources init and shutdown
  nfsd: make NFSd service structure allocated per net
  nfsd: make NFSd service boot time per-net
  nfsd: per-net NFSd up flag introduced
  nfsd: move per-net startup code to separated function
  nfsd: pass net to __write_ports() and down
  nfsd: pass net to nfsd_set_nrthreads()
  ...
2012-12-20 14:04:11 -08:00
Adam Buchbinder
48fc7f7e78 Fix misspellings of "whether" in comments.
"Whether" is misspelled in various comments across the tree; this
fixes them. No code changes.

Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2012-11-19 14:31:35 +01:00
Namjae Jeon
216b6cbdcb exportfs: add FILEID_INVALID to indicate invalid fid_type
This commit adds FILEID_INVALID = 0xff in fid_type to
indicate invalid fid_type

It avoids using magic number 255

Signed-off-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Vivek Trivedi <vtrivedi018@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-11-07 19:22:30 -05:00
Al Viro
2903ff019b switch simple cases of fget_light to fdget
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26 22:20:08 -04:00
Al Viro
d8c9584ea2 vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-06 23:16:53 -05:00
Al Viro
15169fe784 vfs: mnt_id/mnt_group_id moved
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:10 -05:00
Jeff Mahoney
ed5afeaf42 fs/fhandle.c: add <linux/personality.h> for ia64
force_o_largefile() on ia64 is defined in <asm/fcntl.h> and requires
<linux/personality.h>.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-14 16:06:56 -07:00
Aneesh Kumar K.V
becfd1f375 vfs: Add open by file handle support
[AV: duplicate of open() guts removed; file_open_root() used instead]

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-15 02:21:44 -04:00
Aneesh Kumar K.V
990d6c2d7a vfs: Add name to file handle conversion support
The syscall also return mount id which can be used
to lookup file system specific information such as uuid
in /proc/<pid>/mountinfo

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-15 02:21:37 -04:00