File sealing applies protections against certain actions
(currently: write, growth, shrink) at the inode level. New fileops are added
to accommodate seals - EINVAL is returned by fcntl(2) if they are not
implemented.
Reviewed by: markj, kib
Differential Revision: https://reviews.freebsd.org/D21391
fget_unlocked() and fhold().
On sufficiently large machine, f_count can be legitimately very large,
e.g. malicious code can dup same fd up to the per-process
filedescriptors limit, and then fork as much as it can.
On some smaller machine, I see
kern.maxfilesperproc: 939132
kern.maxprocperuid: 34203
which already overflows u_int. More, the malicious code can create
transient references by sending fds over unix sockets.
I realized that this check is missed after reading
https://secfault-security.com/blog/FreeBSD-SA-1902.fd.html
Reviewed by: markj (previous version), mjg
Tested by: pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D20947
fget_mmap() translates rights on the descriptor to a VM protection
mask. It was doing so without holding any locks on the descriptor
table, so a writer could simultaneously be modifying those rights.
Such a situation would be detected using a sequence counter, but
not before an inconsistency could trigger assertion failures in
the capability code.
Fix the problem by copying the fd's rights to a structure on the stack,
and perform the translation only once we know that that snapshot is
consistent.
Reported by: syzbot+ae359438769fda1840f8@syzkaller.appspotmail.com
Reviewed by: brooks, mjg
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20800
VOP_READ and VOP_WRITE take the seqcount in blocks in a 16-bit field.
However, fcntl allows you to set the seqcount in bytes to any nonnegative
31-bit value. The result can be a 16-bit overflow, which will be
sign-extended in functions like ffs_read. Fix this by sanitizing the
argument in kern_fcntl. As a matter of policy, limit to IO_SEQMAX rather
than INT16_MAX.
Also, fifos have overloaded the f_seqcount field for a completely different
purpose ever since r238936. Formalize that by using a union type.
Reviewed by: cem
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20710
A sysid of 0 denotes the local system, and some handlers for remote
locking commands do not attempt to deal with local locks. Note that
F_SETLK_REMOTE is only available to privileged users as it is intended
to be used as a testing interface.
Reviewed by: kib
Reported by: syzbot+9c457a6ae014a3281eb8@syzkaller.appspotmail.com
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19702
Linux generates the content of procfs files using a mechanism prefixed with
seq_*. This in particular came up with recent gcov import.
Sponsored by: The FreeBSD Foundation
1) filecaps_init was unnecesarily a function call
2) an asignment at the end was preventing tail calling of cap_rights_init
Sponsored by: The FreeBSD Foundation
Reading caps is in the hot path (on each successful fd lookup), but
completely unnecessarily requires a function call.
Approved by: re (gjb)
Sponsored by: The FreeBSD Foundation
Replace size_t members with ksize_t (uint64_t) and pointer members
(never used as pointers in userspace, but instead as unique
idenitifiers) with kvaddr_t (uint64_t). This makes the structs
identical between 32-bit and 64-bit ABIs.
On 64-bit bit systems, the ABI is maintained. On 32-bit systems,
this is an ABI breaking change. The ABI of most of these structs
was previously broken in r315662. This also imposes a small API
change on userspace consumers who must handle kernel pointers
becoming virtual addresses.
PR: 228301 (exp-run by antoine)
Reviewed by: jtl, kib, rwatson (various versions)
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D15386
- Add macros to allow preinitialization of cap_rights_t.
- Convert most commonly used code paths to use preinitialized cap_rights_t.
A 3.6% speedup in fstat was measured with this change.
Reported by: mjg
Reviewed by: oshogbo
Approved by: sbruno
MFC after: 1 month
x dup_before
+ dup_after
+------------------------------------------------------------+
| x + |
|x x x x ++ ++|
| |____AM___| |AM||
+------------------------------------------------------------+
N Min Max Median Avg Stddev
x 5 1.514954e+08 1.5230351e+08 1.5206157e+08 1.5199371e+08 341205.71
+ 5 1.5494336e+08 1.5519569e+08 1.5511982e+08 1.5508323e+08 96232.829
Difference at 95.0% confidence
3.08952e+06 +/- 365604
2.03266% +/- 0.245071%
(Student's t, pooled s = 250681)
Reported by: mjg@
MFC after: 1 week
1. check if P_ADVLOCK is already set and if so, don't lock to set it
(stolen from DragonFly)
2. when trying for fast path unlock, check that we are doing unlock
first instead of taking the interlock for no reason (e.g. if we want
to *lock*). whilere make it more likely that falling fast path will
not take the interlock either by checking for state
Note the code is severely pessimized both single- and multithreaded.
fget_cap() tries to do a cheaper snapshot of a file descriptor without
holding the file descriptor lock. This snapshot does not do a deep
copy of the ioctls capability array, but instead uses a different
return value to inform the caller to retry the copy with the lock
held. However, filecaps_copy() was returning 1 to indicate that a
retry was required, and fget_cap() was checking for 0 (actually
'!filecaps_copy()'). As a result, fget_cap() did not do a deep copy
of the ioctls array and just reused the original pointer. This cause
multiple file descriptor entries to think they owned the same pointer
and eventually resulted in duplicate frees.
The only code path that I'm aware of that triggers this is to create a
listen socket that has a restricted list of ioctls and then call
accept() which calls fget_cap() with a valid filecaps structure from
getsock_cap().
To fix, change the return value of filecaps_copy() to return true if
it succeeds in copying the caps and false if it fails because the lock
is required. I find this more intuitive than fixing the caller in
this case. While here, change the return type from 'int' to 'bool'.
Finally, make filecaps_copy() more robust in the failure case by not
copying any of the source filecaps structure over. This avoids the
possibility of leaking a pointer into a structure if a similar future
caller doesn't properly handle the return value from filecaps_copy()
at the expense of one more branch.
I also added a test case that panics before this change and now passes.
Reviewed by: kib
Discussed with: mjg (not a fan of the extra branch)
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D15047
opt_compat.h is mentioned in nearly 180 files. In-progress network
driver compabibility improvements may add over 100 more so this is
closer to "just about everywhere" than "only some files" per the
guidance in sys/conf/options.
Keep COMPAT_LINUX32 in opt_compat.h as it is confined to a subset of
sys/compat/linux/*.c. A fake _COMPAT_LINUX option ensure opt_compat.h
is created on all architectures.
Move COMPAT_LINUXKPI to opt_dontuse.h as it is only used to control the
set of compiled files.
Reviewed by: kib, cem, jhb, jtl
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D14941
pathconf(2) and fpathconf(2) both return a long. The kern_[f]pathconf()
functions now accept a pointer to a long value rather than modifying
td_retval directly. Instead, the system calls explicitly store the
returned long value in td_retval[0].
Requested by: bde
Reviewed by: kib
Sponsored by: Chelsio Communications
The method handles NAME_MAX and LINK_MAX explicitly. For all other
pathconf variables, the method passes the request down to the underlying
file descriptor. This requires splitting a kern_fpathconf() syscallsubr
routine out of sys_fpathconf(). Also, to avoid lock order reversals with
vnode locks, the fdescfs vnode is unlocked around the call to
kern_fpathconf(), but with the usecount of the vnode bumped.
MFC after: 1 month
Sponsored by: Chelsio Communications
Mainly focus on files that use BSD 3-Clause license.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
This makes ddb show files more descriptive and also adjusts the
whitespace to align the columns for non-32-bit architectures.
Reviewed by: cem (previous version), jhb
Approved by: markj (mentor)
Differential Revision: https://reviews.freebsd.org/D11061
inode number or link count for the ABI compat binaries.
Right now, and by default after the change, too large 64bit values are
silently truncated to 32 bits. Enabling the knob causes the system to
return EOVERFLOW for stat(2) family of compat syscalls when some
values cannot be completely represented by the old structures. For
getdirentries(2), knob skips the dirents which would cause non-trivial
truncation of d_ino.
EOVERFLOW error is specified by the X/Open 1996 LFS document
('Adding Support for Arbitrary File Sizes to the Single UNIX
Specification').
Based on the discussion with: bde
Sponsored by: The FreeBSD Foundation
Extend the ino_t, dev_t, nlink_t types to 64-bit ints. Modify
struct dirent layout to add d_off, increase the size of d_fileno
to 64-bits, increase the size of d_namlen to 16-bits, and change
the required alignment. Increase struct statfs f_mntfromname[] and
f_mntonname[] array length MNAMELEN to 1024.
ABI breakage is mitigated by providing compatibility using versioned
symbols, ingenious use of the existing padding in structures, and
by employing other tricks. Unfortunately, not everything can be
fixed, especially outside the base system. For instance, third-party
APIs which pass struct stat around are broken in backward and
forward incompatible ways.
Kinfo sysctl MIBs ABI is changed in backward-compatible way, but
there is no general mechanism to handle other sysctl MIBS which
return structures where the layout has changed. It was considered
that the breakage is either in the management interfaces, where we
usually allow ABI slip, or is not important.
Struct xvnode changed layout, no compat shims are provided.
For struct xtty, dev_t tty device member was reduced to uint32_t.
It was decided that keeping ABI compat in this case is more useful
than reporting 64-bit dev_t, for the sake of pstat.
Update note: strictly follow the instructions in UPDATING. Build
and install the new kernel with COMPAT_FREEBSD11 option enabled,
then reboot, and only then install new world.
Credits: The 64-bit inode project, also known as ino64, started life
many years ago as a project by Gleb Kurtsou (gleb). Kirk McKusick
(mckusick) then picked up and updated the patch, and acted as a
flag-waver. Feedback, suggestions, and discussions were carried
by Ed Maste (emaste), John Baldwin (jhb), Jilles Tjoelker (jilles),
and Rick Macklem (rmacklem). Kris Moore (kris) performed an initial
ports investigation followed by an exp-run by Antoine Brodin (antoine).
Essential and all-embracing testing was done by Peter Holm (pho).
The heavy lifting of coordinating all these efforts and bringing the
project to completion were done by Konstantin Belousov (kib).
Sponsored by: The FreeBSD Foundation (emaste, kib)
Differential revision: https://reviews.freebsd.org/D10439
This allows blind increment of relevant counters which under contention
is cheaper than inc-not-zero loops at least on amd64.
Use it in some of the places which are guaranteed to see already active
vnodes.
Reviewed by: kib (previous version)
always audit the file-descriptor number and vnode information for all
fnctl(2) commands, not just locking-related ones. This was likely an
oversight in the original adaptation of this code from XNU.
MFC after: 3 days
Sponsored by: DARPA, AFRL
If the kernel is not compiled with the CAPABILITIES kernel options
fget_unlocked doesn't return the sequence number so fd_modify will
always report modification, in that case we got infinity loop.
Reported by: br
Reviewed by: mjg
Tested by: br, def
fget_cap_locked returns a referenced file, but the fgetvp_rights does
not need it. Instead, due to the filedesc lock being held, it can
ref the vnode after the file was looked up.
Fix up fget_cap_locked to be consistent with other _locked helpers and not
ref the file.
This plugs a leak introduced in r306184.
Pointy hat to: mjg, oshogbo
