r359473 removed the page unbusy logic from sendfile_iodone() because when
vm_pager_get_pages_async() would return an error after failing to start
the async I/O (eg. because VOP_BMAP failed), sendfile_swapin() would also
unbusy the pages, and it was wrong to unbusy twice. However this breaks
the case where vm_pager_get_pages_async() succeeds in starting an async I/O
and the async I/O is what fails. In this case, sendfile_iodone() must
unbusy the pages, and because sendfile_iodone() doesn't know which case
it is in, sendfile_iodone() must always unbusy pages and relookup pages
which have been substituted with bogus_page, which in turn means that
sendfile_swapin() must never do unbusy or relookup for pages which have
been given to vm_pager_get_pages_async(), even if there is an error.
Reviewed by: kib, markj
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D25136
This commit adds the priv(9) that waters down the sysctl to make it only
allow read(2) of a dirfd by the system root. Jailed root is not allowed, but
jail policy and superuser policy will abstain from allowing/denying it so
that a MAC module can fully control the policy.
Such a MAC module has been written, and can be found at:
https://people.freebsd.org/~kevans/mac_read_dir-0.1.0.tar.gz
It is expected that the MAC module won't be needed by many, as most only
need to do such diagnostics that require this behavior as system root
anyways. Interested parties are welcome to grab the MAC module above and
create a port or locally integrate it, and with enough support it could see
introduction to base. As noted in mac_read_dir.c, it is released under the
BSD 2 clause license and allows the restrictions to be lifted for only
jailed root or for all unprivileged users.
PR: 246412
Reviewed by: mckusick, kib, emaste, jilles, cy, phk, imp (all previous)
Reviewed by: rgrimes (latest version)
Differential Revision: https://reviews.freebsd.org/D24596
Historically, we've allowed read() of a directory and some filesystems will
accommodate (e.g. ufs/ffs, msdosfs). From the history department staffed by
Warner: <<EOF
pdp-7 unix seemed to allow reading directories, but they were weird, special
things there so I'm unsure (my pdp-7 assembler sucks).
1st Edition's sources are lost, mostly. The kernel allows it. The
reconstructed sources from 2nd or 3rd edition read it though.
V6 to V7 changed the filesystem format, and should have been a warning, but
reading directories weren't materially changed.
4.1b BSD introduced readdir because of UFS. UFS broke all directory reading
programs in 1983. ls, du, find, etc all had to be rewritten. readdir() and
friends were introduced here.
SysVr3 picked up readdir() in 1987 for the AT&T fork of Unix. SysVr4 updated
all the directory reading programs in 1988 because different filesystem
types were introduced.
In the 90s, these interfaces became completely ubiquitous as PDP-11s running
V7 faded from view and all the folks that initially started on V7 upgraded
to SysV. Linux never supported this (though I've not done the software
archeology to check) because it has always had a pathological diversity of
filesystems.
EOF
Disallowing read(2) on a directory has the side-effect of masking
application bugs from relying on other implementation's behavior
(e.g. Linux) of rejecting these with EISDIR across the board, but allowing
it has been a vector for at least one stack disclosure bug in the past[0].
By POSIX, this is implementation-defined whether read() handles directories
or not. Popular implementations have chosen to reject them, and this seems
sensible: the data you're reading from a directory is not structured in some
unified way across filesystem implementations like with readdir(2), so it is
impossible for applications to portably rely on this.
With this patch, we will reject most read(2) of a dirfd with EISDIR. Users
that know what they're doing can conscientiously set
bsd.security.allow_read_dir=1 to allow read(2) of directories, as it has
proven useful for debugging or recovery. A future commit will further limit
the sysctl to allow only the system root to read(2) directories, to make it
at least relatively safe to leave on for longer periods of time.
While we're adding logic pertaining to directory vnodes to vn_io_fault, an
additional assertion has also been added to ensure that we're not reaching
vn_io_fault with any write request on a directory vnode. Such request would
be a logical error in the kernel, and must be debugged rather than allowing
it to potentially silently error out.
Commented out shell aliases have been placed in root's chsrc/shrc to promote
awareness that grep may become noisy after this change, depending on your
usage.
A tentative MFC plan has been put together to try and make it as trivial as
possible to identify issues and collect reports; note that this will be
strongly re-evaluated. Tentatively, I will MFC this knob with the default as
it is in HEAD to improve our odds of actually getting reports. The future
priv(9) to further restrict the sysctl WILL NOT BE MERGED BACK, so the knob
will be a faithful reversion on stable/12. We will go into the merge
acknowledging that the sysctl default may be flipped back to restore
historical behavior at *any* point if it's warranted.
[0] https://www.freebsd.org/security/advisories/FreeBSD-SA-19:10.ufs.asc
PR: 246412
Reviewed by: mckusick, kib, emaste, jilles, cy, phk, imp (all previous)
Reviewed by: rgrimes (latest version)
MFC after: 1 month (note the MFC plan mentioned above)
Relnotes: absolutely, but will amend previous RELNOTES entry
Differential Revision: https://reviews.freebsd.org/D24596
r361601 implemented basic support for cleaing the console history buffer.
But after clearing the history buffer, it's not especially useful to be
able to scroll back through that buffer, or for the cursor position to
remain at (very likely) the bottom of the screen.
PR: 224436
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D25079
vfs_export requires security flavors be explicitly listed when
exporting as of r360900.
Use the default AUTH_SYS flavor when converting old export args to
ensure compatibility with the legacy mount syscall.
Reported by: rmacklem
Reviewed by: rmacklem
Approved by: mav (mentor)
MFC after: 3 days
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D25045
Consider this scenario:
- kern.corefile=/var/coredumps/%N.%U.%I.core
- multiple processes with the same name crash at the same time
It's possible that one process selects existing file N as oldvp while it
keeps looking for an unused file number. Another process scans through
files and stumbles upon N. That process would be blocked on the vnode
lock while holding the directory vnode exclusively locked. The first
process would, thus, get blocked on the directory's vnode lock.
More generally, holding a file's vnode lock (oldvp) while trying to lock
its directory (for the next lookup) is a violation of the vnode locking
order.
I have observed this deadlock in the wild.
So, the change to keep oldvp "opened" but unlocked and to lock it again
only if it's to be returned as the result.
As kib noted, an alternative would be to keep the directory locked and
to use VOP_LOOKUP directly for scanning through existing core files.
Reviewed by: kib
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D25027
The nfs-over-tls daemons need a system call to perform operations such as
associate a file descriptor with a krpc socket.
The daemons will not be in head for some time, but it will make it
easier for testers of nfs-over-tls to do testing if the system call
is in head (basically the stub for libc which will be commited soon).
Reviewed by: brooks
Differential Revision: https://reviews.freebsd.org/D24949
For kernel tls, sosend() needs to call ktls_frame() on the mbuf list
to be sent. Without this patch, this was only done when sosend()'s
arguments used a uio_iov and not when an mbuf list is passed in.
At this time, sosend() is never called with an mbuf list argument when
kernel tls is in use, but will be once nfs-over-tls has been incorporated
into head.
Reviewed by: gallatin, glebius
Differential Revision: https://reviews.freebsd.org/D24674
the underlying media fails or becomes inaccessible. For example
when a USB flash memory card hosting a UFS filesystem is unplugged.
The strategy for handling disk I/O errors when soft updates are
enabled is to stop writing to the disk of the affected file system
but continue to accept I/O requests and report that all future
writes by the file system to that disk actually succeed. Then
initiate an asynchronous forced unmount of the affected file system.
There are two cases for disk I/O errors:
- ENXIO, which means that this disk is gone and the lower layers
of the storage stack already guarantee that no future I/O to
this disk will succeed.
- EIO (or most other errors), which means that this particular
I/O request has failed but subsequent I/O requests to this
disk might still succeed.
For ENXIO, we can just clear the error and continue, because we
know that the file system cannot affect the on-disk state after we
see this error. For EIO or other errors, we arrange for the geom_vfs
layer to reject all future I/O requests with ENXIO just like is
done when the geom_vfs is orphaned. In both cases, the file system
code can just clear the error and proceed with the forcible unmount.
This new treatment of I/O errors is needed for writes of any buffer
that is involved in a dependency. Most dependencies are described
by a structure attached to the buffer's b_dep field. But some are
created and processed as a result of the completion of the dependencies
attached to the buffer.
Clearing of some dependencies require a read. For example if there
is a dependency that requires an inode to be written, the disk block
containing that inode must be read, the updated inode copied into
place in that buffer, and the buffer then written back to disk.
Often the needed buffer is already in memory and can be used. But
if it needs to be read from the disk, the read will fail, so we
fabricate a buffer full of zeroes and pretend that the read succeeded.
This zero'ed buffer can be updated and written back to disk.
The only case where a buffer full of zeros causes the code to do
the wrong thing is when reading an inode buffer containing an inode
that still has an inode dependency in memory that will reinitialize
the effective link count (i_effnlink) based on the actual link count
(i_nlink) that we read. To handle this case we now store the i_nlink
value that we wrote in the inode dependency so that it can be
restored into the zero'ed buffer thus keeping the tracking of the
inode link count consistent.
Because applications depend on knowing when an attempt to write
their data to stable storage has failed, the fsync(2) and msync(2)
system calls need to return errors if data fails to be written to
stable storage. So these operations return ENXIO for every call
made on files in a file system where we have otherwise been ignoring
I/O errors.
Coauthered by: mckusick
Reviewed by: kib
Tested by: Peter Holm
Approved by: mckusick (mentor)
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D24088
Some crypto consumers such as GELI and KTLS for file-backed sendfile
need to store their output in a separate buffer from the input.
Currently these consumers copy the contents of the input buffer into
the output buffer and queue an in-place crypto operation on the output
buffer. Using a separate output buffer avoids this copy.
- Create a new 'struct crypto_buffer' describing a crypto buffer
containing a type and type-specific fields. crp_ilen is gone,
instead buffers that use a flat kernel buffer have a cb_buf_len
field for their length. The length of other buffer types is
inferred from the backing store (e.g. uio_resid for a uio).
Requests now have two such structures: crp_buf for the input buffer,
and crp_obuf for the output buffer.
- Consumers now use helper functions (crypto_use_*,
e.g. crypto_use_mbuf()) to configure the input buffer. If an output
buffer is not configured, the request still modifies the input
buffer in-place. A consumer uses a second set of helper functions
(crypto_use_output_*) to configure an output buffer.
- Consumers must request support for separate output buffers when
creating a crypto session via the CSP_F_SEPARATE_OUTPUT flag and are
only permitted to queue a request with a separate output buffer on
sessions with this flag set. Existing drivers already reject
sessions with unknown flags, so this permits drivers to be modified
to support this extension without requiring all drivers to change.
- Several data-related functions now have matching versions that
operate on an explicit buffer (e.g. crypto_apply_buf,
crypto_contiguous_subsegment_buf, bus_dma_load_crp_buf).
- Most of the existing data-related functions operate on the input
buffer. However crypto_copyback always writes to the output buffer
if a request uses a separate output buffer.
- For the regions in input/output buffers, the following conventions
are followed:
- AAD and IV are always present in input only and their
fields are offsets into the input buffer.
- payload is always present in both buffers. If a request uses a
separate output buffer, it must set a new crp_payload_start_output
field to the offset of the payload in the output buffer.
- digest is in the input buffer for verify operations, and in the
output buffer for compute operations. crp_digest_start is relative
to the appropriate buffer.
- Add a crypto buffer cursor abstraction. This is a more general form
of some bits in the cryptosoft driver that tried to always use uio's.
However, compared to the original code, this avoids rewalking the uio
iovec array for requests with multiple vectors. It also avoids
allocate an iovec array for mbufs and populating it by instead walking
the mbuf chain directly.
- Update the cryptosoft(4) driver to support separate output buffers
making use of the cursor abstraction.
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D24545
This reapplies logical r360944 and r360946 (reverting r360955), with fixed
copystr() stand-in replacement macro. Eventually the goal is to convert
consumers and kill the macro, but for a first step it helps if the macro is
correct.
Prior commit message:
Unlike the other copy*() functions, it does not serve to copy from one
address space to another or protect against potential faults. It's just
an older incarnation of the now-more-common strlcpy().
Add a coccinelle script to tools/ which can be used to mechanically
convert existing instances where replacement with strlcpy is trivial.
In the two cases which matched, fuse_vfsops.c and union_vfsops.c, the
code was further refactored manually to simplify.
Replace the declaration of copystr() in systm.h with a small macro
wrapper around strlcpy (with correction from brooks@ -- thanks).
Remove N redundant MI implementations of copystr. For MIPS, this
entailed inlining the assembler copystr into the only consumer,
copyinstr, and making the latter a leaf function.
Reviewed by: jhb (earlier version)
Discussed with: brooks (thanks!)
Differential Revision: https://reviews.freebsd.org/D24672
They depend on it to accurately read the offset.
The new code is not used as it would add an interrupt enable/disable
trip on top of the atomic.
This also fixes a bug where 32-bit nolock request would still lock the offset.
No changes for 64-bit.
Reported by: emaste
Contending cases still serialize on sleepq (which would be taken anyway).
Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D21626
Comparing fsid_t objects requires internal knowledge of the fsid structure
and yet this is duplicated across a number of places in the code.
Simplify by creating a fsidcmp function (macro).
Reviewed by: mjg, rmacklem
Approved by: mav (mentor)
MFC after: 1 week
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D24749
These functions were added in 2001 and are currently unused.
copyinfrom() looks to have never been used. copyinstrfrom() was used
for two weeks before the code was refactored to remove it's sole use.
Reviewed by: brooks, kib
Obtained from: CheriBSD
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D24928
- thr_kill(2) and thr_exit(2) generally (no argument auditing here.
- A set of syscalls for the process descriptor family, specifically:
pdfork(2), pdgetpid(2) and pdkill(2)
For these syscalls, audit the file descriptor. In the case of pdfork(2)
a pointer to an integer (file descriptor) is passed in as an argument.
We audit the post initialized file descriptor (not the random garbage
that would have been passed in). We will also audit the child process
which was created from the fork operation (similar to what is done for
the fork(2) syscall).
pdkill(2) we audit the signal value and fd, and finally pdgetpid(2)
just the file descriptor:
- Following is a sample of the produced audit trails:
header,111,11,pdfork(2),0,Sat May 16 03:07:50 2020, + 394 msec
argument,0,0x39d,child PID
argument,2,0x2,flags
argument,1,0x8,fd
subject,root,root,0,root,0,924,0,0,0.0.0.0
return,success,925
header,79,11,pdgetpid(2),0,Sat May 16 03:07:50 2020, + 394 msec
argument,1,0x8,fd
subject,root,root,0,root,0,924,0,0,0.0.0.0
return,success,0
trailer,79
header,135,11,pdkill(2),0,Sat May 16 03:07:50 2020, + 395 msec
argument,1,0x8,fd
argument,2,0xf,signal
process_ex,root,root,0,root,0,925,0,0,0.0.0.0
subject,root,root,0,root,0,924,0,0,0.0.0.0
return,success,0
trailer,135
MFC after: 1 week
This fixes a race where concurrent calls to doenterpgrp() and
leavepgrp() while TIOCSCTTY is executing may result in tp->t_pgrp
changing value so that tty_rel_pgrp() misses clearing it to NULL. For
more details refer to the use of pgdelete() in the kernel.
No functional change intended.
Panic backtrace:
__mtx_lock_sleep() # page fault due to using destroyed mutex
tty_signal_pgrp()
tty_ioctl()
ptsdev_ioctl()
kern_ioctl()
sys_ioctl()
amd64_syscall()
MFC after: 1 week
Sponsored by: Mellanox Technologies
Reorder flag manipulations and use barrier to ensure that the program
order is followed by compiler and CPU, for unlocked reader of so_state.
In collaboration with: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D24842
Sometimes, when doing read(2) over unix domain socket, for which the
other side socket was closed, read(2) returns -1/ENOTCONN instead of
EOF AKA zero-size read. This is because soreceive_generic() does not
lock socket when testing the so_state SS_ISCONNECTED|SS_ISCONNECTING
flags. It could end up that we do not observe so->so_rcv.sb_state bit
SBS_CANTRCVMORE, and then miss SS_ flags.
Change the test to check that the socket was never connected before
returning ENOTCONN, by adding all state bits for connected.
Reported and tested by: pho
In collaboration with: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D24819
Extattr names are allowed to be 255 bytes -- not 254 bytes plus trailing
NUL. Provide a 256 buffer so that copyinstr() has room for the trailing
NUL.
Re-enable test for maximal name lengths.
PR: 208965
Reported by: asomers
Reviewed by: asomers
Differential Revision: https://reviews.freebsd.org/D24584
Unlike the other copy*() functions, it does not serve to copy from one
address space to another or protect against potential faults. It's just
an older incarnation of the now-more-common strlcpy().
Add a coccinelle script to tools/ which can be used to mechanically
convert existing instances where replacement with strlcpy is trivial.
In the two cases which matched, fuse_vfsops.c and union_vfsops.c, the
code was further refactored manually to simplify.
Replace the declaration of copystr() in systm.h with a small macro
wrapper around strlcpy.
Remove N redundant MI implementations of copystr. For MIPS, this
entailed inlining the assembler copystr into the only consumer,
copyinstr, and making the latter a leaf function.
Reviewed by: jhb
Differential Revision: https://reviews.freebsd.org/D24672
If single-threaded process receives a signal during critical section
established by sigfastblock(2) word, unblock did not caused signal
delivery because sigfastblock(SIGFASTBLOCK_UNBLOCK) failed to request
ast handling of the pending signals.
Set TDF_ASTPENDING | TDF_NEEDSIGCHK on unblock or when kernel forces
end of sigfastblock critical section, to cause syscall exit to recheck
and deliver any signal pending.
Reported by: corydoras@ridiculousfish.com
PR: 246385
Sponsored by: The FreeBSD Foundation
We know the value must be greater than 0 and less than MAXSECFLAVORS.
Reject values outside this range in the initial check in vfs_export and add KASSERTs
in the later consumers.
Also check that we are called with one of either MNT_DELEXPORT or MNT_EXPORTED set.
Reviewed by: rmacklem
Approved by: mav (mentor)
MFC after: 1 week
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D24753
It can be dangerous and there is no need for it in the kernel.
Inspired by Kees Cook's change in Linux, and later OpenBSD.
Reviewed by: cem, gordon, philip
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D24760
This is a general cleanup of the relocatable kernel support on powerpc,
needed to enable kernel ifuncs.
* Fix some relocatable issues in the kernel linker, and change to using
a RELOCATABLE_KERNEL #define instead of #ifdef __powerpc__ for parts that
other platforms can use in the future if they wish to have ET_DYN kernels.
* Get rid of the DB_STOFFS hack now that the kernel is relocated to the DMAP
properly across the board on powerpc64.
* Add powerpc64 and powerpc32 ifunc functionality.
* Allow AIM64 virtual mode OF kernels to run from the DMAP like other AIM64
by implementing a virtual mode restart. This fixes the runtime address on
PowerMac G5.
* Fix symbol relocation problems on post-relocation kernels by relocating
the symbol table.
* Add an undocumented method for supplying kernel symbols on powernv and
other powerpc machines using linux-style kernel/initrd loading -- If
you pass the kernel in as the initrd as well, the copy resident in initrd
will be used as a source for symbols when initializing the debugger.
This method is subject to removal once we have a better way of doing this.
Approved by: jhibbits
Relnotes: yes
Sponsored by: Tag1 Consulting, Inc.
Differential Revision: https://reviews.freebsd.org/D23156
They have more differencies than similarities. For now there is lots
of code that would check for M_EXT only and work correctly on M_EXTPG
buffers, so still carry M_EXT bit together with M_EXTPG. However,
prepare some code for explicit check for M_EXTPG.
Reviewed by: gallatin
Differential Revision: https://reviews.freebsd.org/D24598
o Shrink sglist(9) functions to work with multipage mbufs down from
four functions to two.
o Don't use 'struct mbuf_ext_pgs *' as argument, use struct mbuf.
o Rename to something matching _epg.
Reviewed by: gallatin
Differential Revision: https://reviews.freebsd.org/D24598
next commit brings in second flag, so let them already be in the
future namespace.
Reviewed by: gallatin
Differential Revision: https://reviews.freebsd.org/D24598
