ktrace(2) may toggle trace points in any of
1. a single process
2. all members of a process group
3. all descendents of the processes in 1 or 2
In the first two cases, we do not permit the operation if the process is
being forked or not visible. However, in case 3 we did not enforce this
restriction for descendents. As a result, the assertions about the child
in ktrprocfork() may be violated.
Move these checks into ktrops() so that they are applied consistently.
Allow KTROP_CLEAR for nascent processes. Otherwise, there is a window
where we cannot clear trace points for a nascent child if they are
inherited from the parent.
Reported by: syzbot+d96676592978f137e05c@syzkaller.appspotmail.com
Reported by: syzbot+7c98fcf84a4439f2817f@syzkaller.appspotmail.com
Reviewed by: kib
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30481
ktrstructarray() may be used to create copies of kevent(2) change and
event arrays. It is called before parameter validation is done and so
should check for bogus array lengths before allocating a copy.
Reported by: syzkaller
Reviewed by: kib
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30479
It was possible that termination of ktrace session occured during some
record write, in which case write occured after the close of the vnode.
Use ktr_io_params refcounting to avoid this situation, by taking the
reference on the structure instead of vnode.
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D30400
sys_ktrace() calls namei(), which may call ktrnamei(). But sys_ktrace()
also calls ktrace_enter() first, so if the caller is itself being
traced, the assertion in ktrace_enter() is triggered. And, ktrnamei()
does not check for recursion like most other ktrace ops do.
Fix the bug by simply deferring the ktrace_enter() call.
Also make the parameter to ktrnamei() const and convert to ANSI.
Reported by: syzbot+d0a4de45e58d3c08af4b@syzkaller.appspotmail.com
Reviewed by: kib
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30340
When enabled, writes to ktrace.out that exceed the max file size limit
cause SIGXFSZ as it should be, but note that the limit is taken from
the process that initiated ktrace. When disabled, write is blocked,
but signal is not send.
Note that in either case ktrace for the affected process is stopped.
Requested and reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D30257
Other processes might still be able to write, make the decision to stop
based on the per-process situation.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D30257
detour - it writes ktrace entries to the filesystem - so the overhead
of ast() won't make any difference.
Reviewed by: kib
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D26404
r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly marked).
Use it in preparation for a general review of all nodes.
This is non-functional change that adds annotations to SYSCTL_NODE and
SYSCTL_PROC nodes using one of the soon-to-be-required flags.
Mark all obvious cases as MPSAFE. All entries that haven't been marked
as MPSAFE before are by default marked as NEEDGIANT
Approved by: kib (mentor, blanket)
Commented by: kib, gallatin, melifaro
Differential Revision: https://reviews.freebsd.org/D23718
This eliminates a branch from its consumers trading it for an extra call
if ktrace is enabled for curthread. Given that this is almost never true,
the tradeoff is worth it.
Filesystems which want to use it in limited capacity can employ the
VOP_UNLOCK_FLAGS macro.
Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D21427
KTRPOINT() checks both if we are tracing _and_ if we are recursing within
ktrace. The second condition is only ever executed if ktrace is actually
enabled. This change moves the check out of the hot path in to the functions
themselves.
Discussed with mjg@
Reported by: mjg@
Approved by: sbruno@
- Add a new KTR_STRUCT_ARRAY ktrace record type which dumps an array of
structures.
The structure name in the record payload is preceded by a size_t
containing the size of the individual structures. Use this to
replace the previous code that dumped the kevent arrays dumped for
kevent(). kdump is now able to decode the kevent structures rather
than dumping their contents via a hexdump.
One change from before is that the 'changes' and 'events' arrays are
not marked with separate 'read' and 'write' annotations in kdump
output. Instead, the first array is the 'changes' array, and the
second array (only present if kevent doesn't fail with an error) is
the 'events' array. For kevent(), empty arrays are denoted by an
entry with an array containing zero entries rather than no record.
- Move kevent decoding tables from truss to libsysdecode.
This adds three new functions to decode members of struct kevent:
sysdecode_kevent_filter, sysdecode_kevent_flags, and
sysdecode_kevent_fflags.
kdump uses these helper functions to pretty-print kevent fields.
- Move structure definitions for freebsd11 and freebsd32 kevent
structures to <sys/event.h> so that they can be shared with userland.
The 32-bit structures are only exposed if _WANT_KEVENT32 is defined.
The freebsd11 structures are only exposed if _WANT_FREEBSD11_KEVENT is
defined. The 32-bit freebsd11 structure requires both.
- Decode freebsd11 kevent structures in truss for the compat11.kevent()
system call.
- Log 32-bit kevent structures via ktrace for 32-bit compat kevent()
system calls.
- While here, constify the 'void *data' argument to ktrstruct().
Reviewed by: kib (earlier version)
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D12470
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.
overly large allocation requests.
When ktrace-ing io, sys_kevent() allocates memory to copy the
requested changes and reported events. Allocations are sized by the
incoming syscall lengths arguments, which are user-controlled, and
might cause overflow in calculations or too large allocations.
Since io trace chunks are limited by ktr_geniosize, there is no sense
it even trying to satisfy unbounded allocations. Export ktr_geniosize
and clamp the buffers sizes in advance.
PR: 217435
Reported by: Tim Newsham <tim.newsham@nccgroup.trust>
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
These changes prevent sysctl(8) from returning proper output,
such as:
1) no output from sysctl(8)
2) erroneously returning ENOMEM with tools like truss(1)
or uname(1)
truss: can not get etype: Cannot allocate memory
there is an environment variable which shall initialize the SYSCTL
during early boot. This works for all SYSCTL types both statically and
dynamically created ones, except for the SYSCTL NODE type and SYSCTLs
which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to
be used in the case a tunable sysctl has a custom initialisation
function allowing the sysctl to still be marked as a tunable. The
kernel SYSCTL API is mostly the same, with a few exceptions for some
special operations like iterating childrens of a static/extern SYSCTL
node. This operation should probably be made into a factored out
common macro, hence some device drivers use this. The reason for
changing the SYSCTL API was the need for a SYSCTL parent OID pointer
and not only the SYSCTL parent OID list pointer in order to quickly
generate the sysctl path. The motivation behind this patch is to avoid
parameter loading cludges inside the OFED driver subsystem. Instead of
adding special code to the OFED driver subsystem to post-load tunables
into dynamically created sysctls, we generalize this in the kernel.
Other changes:
- Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask"
to "hw.pcic.intr_mask".
- Removed redundant TUNABLE statements throughout the kernel.
- Some minor code rewrites in connection to removing not needed
TUNABLE statements.
- Added a missing SYSCTL_DECL().
- Wrapped two very long lines.
- Avoid malloc()/free() inside sysctl string handling, in case it is
called to initialize a sysctl from a tunable, hence malloc()/free() is
not ready when sysctls from the sysctl dataset are registered.
- Bumped FreeBSD version to indicate SYSCTL API change.
MFC after: 2 weeks
Sponsored by: Mellanox Technologies
In the .o file, this only changes some line numbers (head amd64) because
element 0 is no longer explicitly initialized.
This should make bugs like FreeBSD-SA-14:12.ktrace less likely.
Discussed with: des
MFC after: 1 week
further refinement is required as some device drivers intended to be
portable over FreeBSD versions rely on __FreeBSD_version to decide whether
to include capability.h.
MFC after: 3 weeks
While here, correct all consumers to pass NULL instead of 0 as we pass
capability rights as pointers now, not uint64_t.
Reported by: Daniel Peyrolon
Tested by: Daniel Peyrolon
Approved by: re (marius)
in the future in a backward compatible (API and ABI) way.
The cap_rights_t represents capability rights. We used to use one bit to
represent one right, but we are running out of spare bits. Currently the new
structure provides place for 114 rights (so 50 more than the previous
cap_rights_t), but it is possible to grow the structure to hold at least 285
rights, although we can make it even larger if 285 rights won't be enough.
The structure definition looks like this:
struct cap_rights {
uint64_t cr_rights[CAP_RIGHTS_VERSION + 2];
};
The initial CAP_RIGHTS_VERSION is 0.
The top two bits in the first element of the cr_rights[] array contain total
number of elements in the array - 2. This means if those two bits are equal to
0, we have 2 array elements.
The top two bits in all remaining array elements should be 0.
The next five bits in all array elements contain array index. Only one bit is
used and bit position in this five-bits range defines array index. This means
there can be at most five array elements in the future.
To define new right the CAPRIGHT() macro must be used. The macro takes two
arguments - an array index and a bit to set, eg.
#define CAP_PDKILL CAPRIGHT(1, 0x0000000000000800ULL)
We still support aliases that combine few rights, but the rights have to belong
to the same array element, eg:
#define CAP_LOOKUP CAPRIGHT(0, 0x0000000000000400ULL)
#define CAP_FCHMOD CAPRIGHT(0, 0x0000000000002000ULL)
#define CAP_FCHMODAT (CAP_FCHMOD | CAP_LOOKUP)
There is new API to manage the new cap_rights_t structure:
cap_rights_t *cap_rights_init(cap_rights_t *rights, ...);
void cap_rights_set(cap_rights_t *rights, ...);
void cap_rights_clear(cap_rights_t *rights, ...);
bool cap_rights_is_set(const cap_rights_t *rights, ...);
bool cap_rights_is_valid(const cap_rights_t *rights);
void cap_rights_merge(cap_rights_t *dst, const cap_rights_t *src);
void cap_rights_remove(cap_rights_t *dst, const cap_rights_t *src);
bool cap_rights_contains(const cap_rights_t *big, const cap_rights_t *little);
Capability rights to the cap_rights_init(), cap_rights_set(),
cap_rights_clear() and cap_rights_is_set() functions are provided by
separating them with commas, eg:
cap_rights_t rights;
cap_rights_init(&rights, CAP_READ, CAP_WRITE, CAP_FSTAT);
There is no need to terminate the list of rights, as those functions are
actually macros that take care of the termination, eg:
#define cap_rights_set(rights, ...) \
__cap_rights_set((rights), __VA_ARGS__, 0ULL)
void __cap_rights_set(cap_rights_t *rights, ...);
Thanks to using one bit as an array index we can assert in those functions that
there are no two rights belonging to different array elements provided
together. For example this is illegal and will be detected, because CAP_LOOKUP
belongs to element 0 and CAP_PDKILL to element 1:
cap_rights_init(&rights, CAP_LOOKUP | CAP_PDKILL);
Providing several rights that belongs to the same array's element this way is
correct, but is not advised. It should only be used for aliases definition.
This commit also breaks compatibility with some existing Capsicum system calls,
but I see no other way to do that. This should be fine as Capsicum is still
experimental and this change is not going to 9.x.
Sponsored by: The FreeBSD Foundation
In particular, do not lock Giant conditionally when calling into the
filesystem module, remove the VFS_LOCK_GIANT() and related
macros. Stop handling buffers belonging to non-mpsafe filesystems.
The VFS_VERSION is bumped to indicate the interface change which does
not result in the interface signatures changes.
Conducted and reviewed by: attilio
Tested by: pho
a pair of records similar to syscall entry and return that a user can
use to determine how long page faults take. The new ktrace records are
enabled via the 'p' trace type, and are enabled in the default set of
trace points.
Reviewed by: kib
MFC after: 2 weeks
Add the sysctl debug.iosize_max_clamp, enabled by default. Setting the
sysctl to zero allows to perform the SSIZE_MAX-sized i/o requests from
the usermode.
Discussed with: bde, das (previous versions)
MFC after: 1 month
only logged instances where an operation on a file descriptor required
capabilities which the file descriptor did not have. By adding a type enum
to struct ktr_cap_fail, we can catch other types of capability failures as
well, such as disallowed system calls or attempts to wrap a file descriptor
with more capabilities than it had to begin with.
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.
Reviewed by: rwatson
Approved by: re (bz)
The reason for this is a bug at ktrops() where process dereferenced
without having a lock. This might cause a panic if ktrace was runned
with -p flag and the specified process exited between the dropping
a lock and writing sv_flags.
Since it is impossible to acquire sx lock while holding mtx switch
to use asynchronous enqueuerequest() instead of writerequest().
Rename ktr_getrequest_ne() to more understandable name [1].
Requested by: jhb [1]
MFC after: 1 Week
traced process by adding two new events which records value of process
sv_flags to the trace file at process creation/execing/exiting time.
MFC after: 1 Month.
1) do not take a lock around the single atomic operation.
2) do not lose the invariant of lock by dropping/acquiring
ktrace_mtx around free() or malloc().
MFC after: 1 Month.
PMC/SYSV/...).
No FreeBSD version bump, the userland application to query the features will
be committed last and can serve as an indication of the availablility if
needed.
Sponsored by: Google Summer of Code 2010
Submitted by: kibab
Reviewed by: arch@ (parts by rwatson, trasz, jhb)
X-MFC after: to be determined in last commit with code from this project
may be left. This fixes a memory leak that can occur when tracing is
disabled on a process via disabling tracing of a specific file (or if
an I/O error occurs with the tracefile) if the process's next system
call is exit(). The trace disabling code clears p_traceflag, so exit1()
doesn't do any KTRACE-related cleanup leading to the leak. I chose to
make the free'ing of pending records synchronous rather than patching
exit1().
- Move KTRACE-specific logic out of kern_(exec|exit|fork).c and into
kern_ktrace.c instead. Make ktrace_mtx private to kern_ktrace.c as a
result.
MFC after: 1 month
