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Implement NFSv41 ACLs through xattr #10

Merged
merged 5 commits into from
May 24, 2021
Merged

Implement NFSv41 ACLs through xattr #10

merged 5 commits into from
May 24, 2021

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anodos325
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@anodos325 anodos325 commented May 6, 2021 •
edited by ghost
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This implements NFSv41 (RFC 5661) ACLs in a manner
compatible with vfs_nfs4acl_xattr in Samba and
nfs4xdr-acl-tools.

There are three key areas of change in this commit:

  1. NFSv4 ACL management through system.nfs4_acl_xdr xattr.
    Install an xattr handler for "system.nfs4_acl_xdr" that
    presents an xattr containing full NFSv41 ACL structures
    generated through rpcgen using specification from the Samba
    project. This xattr is used by userspace programs to read and
    set permissions.

  2. add an i_op->permissions endpoint: zpl_permissions(). This
    is used by the VFS in Linux to determine whether to allow /
    deny an operation. Wherever possible, we try to avoid having
    to call zfs_access(). If kernel has NFSv4 patch for VFS, then
    perform more complete check of avaiable access mask.

  3. add capability-based overrides to secpolicy_vnode_access2()
    there are various situations in which ACL may need to be
    overridden based on capabilities. This logic is almost directly
    copied from Linux VFS. For instance, root needs to be able to
    always read / write ACLs (otherwise admin can get locked out
    from files).

This is commit was initially inspired by work from Paul B. Henson
to implement NFSv4.0 (RFC3530) ACLs in ZFS on Linux. Key areas of
divergence are as follows:

  • ACL specification, xattr format, xattr name
  • Addition of handling for NFSv4 masks from Linux VFS
  • Addition of ACL overrides based on capabilities

Signed-off-by: Andrew Walker awalker@ixsystems.com

Motivation and Context

Description

How Has This Been Tested?

Types of changes

  • Bug fix (non-breaking change which fixes an issue)
  • New feature (non-breaking change which adds functionality)
  • Performance enhancement (non-breaking change which improves efficiency)
  • Code cleanup (non-breaking change which makes code smaller or more readable)
  • Breaking change (fix or feature that would cause existing functionality to change)
  • Documentation (a change to man pages or other documentation)

Checklist:

  • My code follows the ZFS on Linux code style requirements.
  • I have updated the documentation accordingly.
  • I have read the contributing document.
  • I have added tests to cover my changes.
  • I have run the ZFS Test Suite with this change applied.
  • All commit messages are properly formatted and contain Signed-off-by.

@anodos325 anodos325 added the WIP Work In Progress label May 6, 2021
@anodos325
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Currently rebasing on OpenZFS 2.1

@ghost ghost force-pushed the truenas/zfs-2.1-release branch 2 times, most recently from a4d5b0f to 7af6852 Compare May 11, 2021 20:57
@anodos325 anodos325 requested a review from rick-mesta May 14, 2021 13:13
@ghost ghost force-pushed the truenas/zfs-2.1-release branch from 7af6852 to 8e040c7 Compare May 14, 2021 15:21
@anodos325
Implement NFSv41 ACLs through xattr
4b4d34d 
This implements NFSv41 (RFC 5661) ACLs in a manner
compatible with vfs_nfs4acl_xattr in Samba and
nfs4xdr-acl-tools.

There are three key areas of change in this commit:
1) NFSv4 ACL management through system.nfs4_acl_xdr xattr.
  Install an xattr handler for "system.nfs4_acl_xdr" that
  presents an xattr containing full NFSv41 ACL structures
  generated through rpcgen using specification from the Samba
  project. This xattr is used by userspace programs to read and
  set permissions.

2) add an i_op->permissions endpoint: zpl_permissions(). This
  is used by the VFS in Linux to determine whether to allow /
  deny an operation. Wherever possible, we try to avoid having
  to call zfs_access(). If kernel has NFSv4 patch for VFS, then
  perform more complete check of avaiable access mask.

3) add capability-based overrides to secpolicy_vnode_access2()
  there are various situations in which ACL may need to be
  overridden based on capabilities. This logic is almost directly
  copied from Linux VFS. For instance, root needs to be able to
  always read / write ACLs (otherwise admin can get locked out
  from files).

This is commit was initially inspired by work from Paul B. Henson
to implement NFSv4.0 (RFC3530) ACLs in ZFS on Linux. Key areas of
divergence are as follows:
- ACL specification, xattr format, xattr name
- Addition of handling for NFSv4 masks from Linux VFS
- Addition of ACL overrides based on capabilities

Signed-off-by: Andrew Walker <awalker@ixsystems.com>
@anodos325
Fixes for checkstyle
7bf157e 
Exclude rpcgen generated files from cstyle check and
add gitignore for rpcgen created files.

Signed-off-by: Andrew Walker <awalker@ixsystems.com>
@anodos325
Add blank line after variables
01cde40 
Signed-off-by: Andrew Walker <awalker@ixsystems.com>
ghost
ghost reviewed May 17, 2021
View reviewed changes
module/Makefile.in Outdated Show resolved Hide resolved
ghost
ghost reviewed May 17, 2021
View reviewed changes
module/os/linux/zfs/policy.c Outdated Show resolved Hide resolved
@anodos325
Simplify check in zpl_permission()
d86fc0e 
Signed-off-by: Andrew Walker <awalker@ixsystems.com>
@anodos325
pop diagnostic override at end of nfs4acl_xdr.c
9bf8866 
Signed-off-by: Andrew Walker <awalker@ixsystems.com>
@anodos325 anodos325 merged commit ae7e6ca into truenas/zfs-2.1-release May 24, 2021
@anodos325 anodos325 deleted the NAS-103664 branch May 24, 2021 14:49
@ghost ghost removed the WIP Work In Progress label Jul 6, 2021
@ghost ghost mentioned this pull request Jul 6, 2021
Closed
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ixhamza pushed a commit that referenced this pull request Mar 20, 2023
@rob-wing
FreeBSD: don't verify recycled vnode for zfs control directory
28251d8 
Under certain loads, the following panic is hit:

    panic: page fault
    KDB: stack backtrace:
    #0 0xffffffff805db025 at kdb_backtrace+0x65
    #1 0xffffffff8058e86f at vpanic+0x17f
    #2 0xffffffff8058e6e3 at panic+0x43
    #3 0xffffffff808adc15 at trap_fatal+0x385
    #4 0xffffffff808adc6f at trap_pfault+0x4f
    #5 0xffffffff80886da8 at calltrap+0x8
    #6 0xffffffff80669186 at vgonel+0x186
    #7 0xffffffff80669841 at vgone+0x31
    #8 0xffffffff8065806d at vfs_hash_insert+0x26d
    #9 0xffffffff81a39069 at sfs_vgetx+0x149
    #10 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
    #11 0xffffffff8065a28c at lookup+0x45c
    #12 0xffffffff806594b9 at namei+0x259
    #13 0xffffffff80676a33 at kern_statat+0xf3
    #14 0xffffffff8067712f at sys_fstatat+0x2f
    #15 0xffffffff808ae50c at amd64_syscall+0x10c
    #16 0xffffffff808876bb at fast_syscall_common+0xf8

The page fault occurs because vgonel() will call VOP_CLOSE() for active
vnodes. For this reason, define vop_close for zfsctl_ops_snapshot. While
here, define vop_open for consistency.

After adding the necessary vop, the bug progresses to the following
panic:

    panic: VERIFY3(vrecycle(vp) == 1) failed (0 == 1)
    cpuid = 17
    KDB: stack backtrace:
    #0 0xffffffff805e29c5 at kdb_backtrace+0x65
    #1 0xffffffff8059620f at vpanic+0x17f
    #2 0xffffffff81a27f4a at spl_panic+0x3a
    #3 0xffffffff81a3a4d0 at zfsctl_snapshot_inactive+0x40
    #4 0xffffffff8066fdee at vinactivef+0xde
    #5 0xffffffff80670b8a at vgonel+0x1ea
    #6 0xffffffff806711e1 at vgone+0x31
    #7 0xffffffff8065fa0d at vfs_hash_insert+0x26d
    #8 0xffffffff81a39069 at sfs_vgetx+0x149
    #9 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
    #10 0xffffffff80661c2c at lookup+0x45c
    #11 0xffffffff80660e59 at namei+0x259
    #12 0xffffffff8067e3d3 at kern_statat+0xf3
    #13 0xffffffff8067eacf at sys_fstatat+0x2f
    #14 0xffffffff808b5ecc at amd64_syscall+0x10c
    #15 0xffffffff8088f07b at fast_syscall_common+0xf8

This is caused by a race condition that can occur when allocating a new
vnode and adding that vnode to the vfs hash. If the newly created vnode
loses the race when being inserted into the vfs hash, it will not be
recycled as its usecount is greater than zero, hitting the above
assertion.

Fix this by dropping the assertion.

FreeBSD-issue: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=252700
Reviewed-by: Andriy Gapon <avg@FreeBSD.org>
Reviewed-by: Mateusz Guzik <mjguzik@gmail.com>
Reviewed-by: Alek Pinchuk <apinchuk@axcient.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Rob Wing <rob.wing@klarasystems.com>
Co-authored-by: Rob Wing <rob.wing@klarasystems.com>
Submitted-by: Klara, Inc.
Sponsored-by: rsync.net
Closes openzfs#14501
ixhamza pushed a commit that referenced this pull request Jun 12, 2023
@rob-wing @behlendorf
FreeBSD: don't verify recycled vnode for zfs control directory
f786232 
Under certain loads, the following panic is hit:

    panic: page fault
    KDB: stack backtrace:
    #0 0xffffffff805db025 at kdb_backtrace+0x65
    #1 0xffffffff8058e86f at vpanic+0x17f
    #2 0xffffffff8058e6e3 at panic+0x43
    #3 0xffffffff808adc15 at trap_fatal+0x385
    #4 0xffffffff808adc6f at trap_pfault+0x4f
    #5 0xffffffff80886da8 at calltrap+0x8
    #6 0xffffffff80669186 at vgonel+0x186
    #7 0xffffffff80669841 at vgone+0x31
    #8 0xffffffff8065806d at vfs_hash_insert+0x26d
    #9 0xffffffff81a39069 at sfs_vgetx+0x149
    #10 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
    #11 0xffffffff8065a28c at lookup+0x45c
    #12 0xffffffff806594b9 at namei+0x259
    #13 0xffffffff80676a33 at kern_statat+0xf3
    #14 0xffffffff8067712f at sys_fstatat+0x2f
    #15 0xffffffff808ae50c at amd64_syscall+0x10c
    #16 0xffffffff808876bb at fast_syscall_common+0xf8

The page fault occurs because vgonel() will call VOP_CLOSE() for active
vnodes. For this reason, define vop_close for zfsctl_ops_snapshot. While
here, define vop_open for consistency.

After adding the necessary vop, the bug progresses to the following
panic:

    panic: VERIFY3(vrecycle(vp) == 1) failed (0 == 1)
    cpuid = 17
    KDB: stack backtrace:
    #0 0xffffffff805e29c5 at kdb_backtrace+0x65
    #1 0xffffffff8059620f at vpanic+0x17f
    #2 0xffffffff81a27f4a at spl_panic+0x3a
    #3 0xffffffff81a3a4d0 at zfsctl_snapshot_inactive+0x40
    #4 0xffffffff8066fdee at vinactivef+0xde
    #5 0xffffffff80670b8a at vgonel+0x1ea
    #6 0xffffffff806711e1 at vgone+0x31
    #7 0xffffffff8065fa0d at vfs_hash_insert+0x26d
    #8 0xffffffff81a39069 at sfs_vgetx+0x149
    #9 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
    #10 0xffffffff80661c2c at lookup+0x45c
    #11 0xffffffff80660e59 at namei+0x259
    #12 0xffffffff8067e3d3 at kern_statat+0xf3
    #13 0xffffffff8067eacf at sys_fstatat+0x2f
    #14 0xffffffff808b5ecc at amd64_syscall+0x10c
    #15 0xffffffff8088f07b at fast_syscall_common+0xf8

This is caused by a race condition that can occur when allocating a new
vnode and adding that vnode to the vfs hash. If the newly created vnode
loses the race when being inserted into the vfs hash, it will not be
recycled as its usecount is greater than zero, hitting the above
assertion.

Fix this by dropping the assertion.

FreeBSD-issue: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=252700
Reviewed-by: Andriy Gapon <avg@FreeBSD.org>
Reviewed-by: Mateusz Guzik <mjguzik@gmail.com>
Reviewed-by: Alek Pinchuk <apinchuk@axcient.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Rob Wing <rob.wing@klarasystems.com>
Co-authored-by: Rob Wing <rob.wing@klarasystems.com>
Submitted-by: Klara, Inc.
Sponsored-by: rsync.net
Closes openzfs#14501
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