Currently sizeof(struct filedesc0) is 1096 bytes, which means allocations from
malloc use 2048 bytes.
There is no easy way to shrink the structure <= 1024 an it is likely to grow in
the future.
appropriately
Assert FILEDESC_XLOCK_ASSERT only for already used tables in fdgrowtable.
We don't have to call it with the lock held if we are just creating new
filedesc.
As a side note, strictly speaking processes can have fdtables with
fd_lastfile = -1, but then they cannot enter fdgrowtable. Very first file
descriptor they get will be 0 and the only syscall allowing to choose fd number
requires an active file descriptor. Should this ever change, we can add an 'init'
(or similar) parameter to fdgrowtable.
While here add 'fdused_init' which does not perform unnecessary work.
Drop FILEDESC_LOCK_ASSERT from fdisused and rely on callers to hold
it when appropriate. This function is only used with INVARIANTS.
No functional changes intended.
Test for file availability by fde_file != NULL instead of fdisused, this is
consistent with similar checks later.
Drop badfileops check. badfileops don't have DFLAG_PASSABLE set, so it was never
reached in practice.
fdiused is now only used in some KASSERTS, so ifdef it under INVARIANTS.
No functional changes.
without restarting whole lookup
Restart is only needed when fp was closed by current process, which is a much
rarer event than ref/deref by some other thread.
A read barrier was necessary because fd table pointer and table size were
updated separately, opening a window where fget_unlocked could read new size
and old pointer.
This patch puts both these fields into one dedicated structure, pointer to which
is later atomically updated. As such, fget_unlocked only needs data a dependency
barrier which is a noop on all supported architectures.
Reviewed by: kib (previous version)
MFC after: 2 weeks
Rename it to fdsetugidsafety for consistency with other functions.
There is no need to take filedesc lock if not closing any files.
The loop has to verify each file and we are guaranteed fdtable has space
for at least 20 fds. As such there is no need to check fd_lastfile.
While here tidy up is_unsafe.
- Wrong integer type was specified.
- Wrong or missing "access" specifier. The "access" specifier
sometimes included the SYSCTL type, which it should not, except for
procedural SYSCTL nodes.
- Logical OR where binary OR was expected.
- Properly assert the "access" argument passed to all SYSCTL macros,
using the CTASSERT macro. This applies to both static- and dynamically
created SYSCTLs.
- Properly assert the the data type for both static and dynamic
SYSCTLs. In the case of static SYSCTLs we only assert that the data
pointed to by the SYSCTL data pointer has the correct size, hence
there is no easy way to assert types in the C language outside a
C-function.
- Rewrote some code which doesn't pass a constant "access" specifier
when creating dynamic SYSCTL nodes, which is now a requirement.
- Updated "EXAMPLES" section in SYSCTL manual page.
MFC after: 3 days
Sponsored by: Mellanox Technologies
Include sequence counter supports incoditionally [1]. This fixes reprted build
problems with e.g. nvidia driver due to missing opt_capsicum.h.
Replace fishy looking sizeof with offsetof. Make fde_seq the last member in
order to simplify calculations.
Suggested by: kib [1]
X-MFC: with 272505
the upper layers, which interpret it as errno value, which happens to
be ERESTART. The result was spurious restarts of the sysctls in loop,
e.g. kern.proc.proc, instead of returning ENOMEM to caller.
Convert -1 from sbuf_bcat() to ENOMEM, when returning to the callers
expecting errno.
In collaboration with: pho
Sponsored by: The FreeBSD Foundation (kib)
MFC after: 1 week
fp and appropriate capability lookups were not atomic, which could result in
improper capabilities being checked.
This could result either in protection bypass or in a spurious ENOTCAPABLE.
Make fp + capability check atomic with the help of sequence counters.
Reviewed by: kib
MFC after: 3 weeks
struct flock are done in the sys_fcntl(), which mean that compat32 used
direct access to userland pointers.
Move code from sys_fcntl() to new wrapper, kern_fcntl_freebsd(), which
performs neccessary userland memory accesses, and use it from both
native and compat32 fcntl syscalls.
Reported by: jhibbits
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
struct kinfo_file.
- Move the various fill_*_info() methods out of kern_descrip.c and into the
various file type implementations.
- Rework the support for kinfo_ofile to generate a suitable kinfo_file object
for each file and then convert that to a kinfo_ofile structure rather than
keeping a second, different set of code that directly manipulates
type-specific file information.
- Remove the shm_path() and ksem_info() layering violations.
Differential Revision: https://reviews.freebsd.org/D775
Reviewed by: kib, glebius (earlier version)
- Add invfo_rdwr() (for read and write), invfo_ioctl(), invfo_poll(),
and invfo_kqfilter() for use by file types that do not support the
respective operations. Home-grown versions of invfo_poll() were
universally broken (they returned an errno value, invfo_poll()
uses poll_no_poll() to return an appropriate event mask). Home-grown
ioctl routines also tended to return an incorrect errno (invfo_ioctl
returns ENOTTY).
- Use the invfo_*() functions instead of local versions for
unsupported file operations.
- Reorder fileops members to match the order in the structure definition
to make it easier to spot missing members.
- Add several missing methods to linuxfileops used by the OFED shim
layer: fo_write(), fo_truncate(), fo_kqfilter(), and fo_stat(). Most
of these used invfo_*(), but a dummy fo_stat() implementation was
added.
instead of breaking out of the loop and then immediately checking the loop
index so that if it was broken out of the proper value can be returned.
While here, use nitems().
Code trying to take a look has to check fd_refcnt and it is 0 by that time.
This is a follow up to r268505, without this the code would leak memory for
tables bigger than the default.
MFC after: 1 week
Filetable can be shared with other processes. Previous code failed to
clear the pointer for all but the last process getting rid of the table.
This is mostly cosmetics.
Get rid of 'This should happen earlier' comment. Clearing the pointer in
this place is fine as consumers can reliably check for files availability
by inspecting fd_refcnt and vnodes availabity by NULL-checking them.
MFC after: 1 week
o assert in each one that fdp is not shared
o remove unnecessary NULL checks - all userspace processes have fdtables
and kernel processes cannot execve
o remove comments about the danger of fd_ofiles getting reallocated - fdtable
is not shared and fd_ofiles could be only reallocated if new fd was about to be
added, but if that was possible the code would already be buggy as setugidsafety
work could be undone
MFC after: 1 week
We can read refcnt safely and only care if it is equal to 1.
If it could suddenly change from 1 to something bigger the code would be
buggy even in the previous form and transitions from > 1 to 1 are equally racy
and harmless (we copy even though there is no need).
MFC after: 1 week
fd_lastfile is guaranteed to be the biggest open fd, so when the intent
is to iterate over active fds or lookup one, there is no point in looking
beyond that limit.
Few places are left unpatched for now.
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
to use-after-free.
fdescfree proceeds to free file pointers once fd_refcnt reaches 0, but
kern_proc_{o,}filedesc_out only checked for hold count.
MFC after: 3 days
fdgrowtable() now only reallocates fd_map when necessary.
This fixes fdgrowtable() to use the same logic as fdescfree() for
when to free the fd_map. The logic in fdescfree() is intended to
not free the initial static allocation, however the fd_map grows
at a slower rate than the table does. The table is intended to hold
20 fd, but its initial map has many more slots than 20. The slot
sizing causes NDSLOTS(20) through NDSLOTS(63) to be 1 which matches
NDSLOTS(20), so fdescfree() was assuming that the fd_map was still
the initial allocation and not freeing it.
This partially reverts r244510 by reintroducing some of the logic
it removed in fdgrowtable().
Reviewed by: mjg
Approved by: bapt (mentor)
MFC after: 2 weeks
Callers do that already and additional check races with process
decreasing limits and can result in not growing the table at all, which
is currently not handled.
MFC after: 3 days
for extending and reusing it.
The sendfile_sync wrapper is mostly just a "mbuf transaction" wrapper,
used to indicate that the backing store for a group of mbufs has completed.
It's only being used by sendfile for now and it's only implementing a
sleep/wakeup rendezvous. However, there are other potential signaling
paths (kqueue) and other potential uses (socket zero-copy write) where the
same mechanism would also be useful.
So, with that in mind:
* extract the sendfile_sync code out into sf_sync_*() methods
* teach the sf_sync_alloc method about the current config flag -
it will eventually know about kqueue.
* move the sendfile_sync code out of do_sendfile() - the only thing
it now knows about is the sfs pointer. The guts of the sync
rendezvous (setup, rendezvous/wait, free) is now done in the
syscall wrapper.
* .. and teach the 32-bit compat sendfile call the same.
This should be a no-op. It's primarily preparation work for teaching
the sendfile_sync about kqueue notification.
Tested:
* Peter Holm's sendfile stress / regression scripts
Sponsored by: Netflix, Inc.
requires process descriptors to work and having PROCDESC in GENERIC
seems not enough, especially that we hope to have more and more consumers
in the base.
MFC after: 3 days
allocated, but the old table is kept around to handle the case of
threads still performing unlocked accesses to it.
Grow the table exponentially instead of increasing its size by
sizeof(long) * 8 chunks when overflowing. This mode significantly
reduces the total memory use for the processes consuming large numbers
of the file descriptors which open them one by one.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Approved by: re (marius)
seeing a stale fd_ofiles table once fd_nfiles is already updated,
resulting in OOB accesses.
Approved by: re (kib)
Sponsored by: EMC / Isilon storage division
Reported and tested by: pho
Reviewed by: benno
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
The filedesc lock may not be dropped unconditionally before exporting
fd to sbuf: fd might go away during execution. While it is ok for
DTYPE_VNODE and DTYPE_FIFO because the export is from a vrefed vnode
here, for other types it is unsafe.
Instead, drop the lock in export_fd_to_sb(), after preparing data in
memory and before writing to sbuf.
Spotted by: mjg
Suggested by: kib
Review by: kib
MFC after: 1 week
kernel-based POSIX semaphore descriptors to userland via procstat(1) and
fstat(1):
- Change sem file descriptors to track the pathname they are associated
with and add a ksem_info() method to copy the path out to a
caller-supplied buffer.
- Use the fo_stat() method of shared memory objects and ksem_info() to
export the path, mode, and value of a semaphore via struct kinfo_file.
- Add a struct semstat to the libprocstat(3) interface along with a
procstat_get_sem_info() to export the mode and value of a semaphore.
- Teach fstat about semaphores and to display their path, mode, and value.
MFC after: 2 weeks
and kern_proc_vmmap_out() functions to output process kinfo structures
to sbuf, to make the code reusable.
The functions are going to be used in the coredump routine to store
procstat info in the core program header notes.
Reviewed by: kib
MFC after: 3 weeks
- Capability is no longer separate descriptor type. Now every descriptor
has set of its own capability rights.
- The cap_new(2) system call is left, but it is no longer documented and
should not be used in new code.
- The new syscall cap_rights_limit(2) should be used instead of
cap_new(2), which limits capability rights of the given descriptor
without creating a new one.
- The cap_getrights(2) syscall is renamed to cap_rights_get(2).
- If CAP_IOCTL capability right is present we can further reduce allowed
ioctls list with the new cap_ioctls_limit(2) syscall. List of allowed
ioctls can be retrived with cap_ioctls_get(2) syscall.
- If CAP_FCNTL capability right is present we can further reduce fcntls
that can be used with the new cap_fcntls_limit(2) syscall and retrive
them with cap_fcntls_get(2).
- To support ioctl and fcntl white-listing the filedesc structure was
heavly modified.
- The audit subsystem, kdump and procstat tools were updated to
recognize new syscalls.
- Capability rights were revised and eventhough I tried hard to provide
backward API and ABI compatibility there are some incompatible changes
that are described in detail below:
CAP_CREATE old behaviour:
- Allow for openat(2)+O_CREAT.
- Allow for linkat(2).
- Allow for symlinkat(2).
CAP_CREATE new behaviour:
- Allow for openat(2)+O_CREAT.
Added CAP_LINKAT:
- Allow for linkat(2). ABI: Reuses CAP_RMDIR bit.
- Allow to be target for renameat(2).
Added CAP_SYMLINKAT:
- Allow for symlinkat(2).
Removed CAP_DELETE. Old behaviour:
- Allow for unlinkat(2) when removing non-directory object.
- Allow to be source for renameat(2).
Removed CAP_RMDIR. Old behaviour:
- Allow for unlinkat(2) when removing directory.
Added CAP_RENAMEAT:
- Required for source directory for the renameat(2) syscall.
Added CAP_UNLINKAT (effectively it replaces CAP_DELETE and CAP_RMDIR):
- Allow for unlinkat(2) on any object.
- Required if target of renameat(2) exists and will be removed by this
call.
Removed CAP_MAPEXEC.
CAP_MMAP old behaviour:
- Allow for mmap(2) with any combination of PROT_NONE, PROT_READ and
PROT_WRITE.
CAP_MMAP new behaviour:
- Allow for mmap(2)+PROT_NONE.
Added CAP_MMAP_R:
- Allow for mmap(PROT_READ).
Added CAP_MMAP_W:
- Allow for mmap(PROT_WRITE).
Added CAP_MMAP_X:
- Allow for mmap(PROT_EXEC).
Added CAP_MMAP_RW:
- Allow for mmap(PROT_READ | PROT_WRITE).
Added CAP_MMAP_RX:
- Allow for mmap(PROT_READ | PROT_EXEC).
Added CAP_MMAP_WX:
- Allow for mmap(PROT_WRITE | PROT_EXEC).
Added CAP_MMAP_RWX:
- Allow for mmap(PROT_READ | PROT_WRITE | PROT_EXEC).
Renamed CAP_MKDIR to CAP_MKDIRAT.
Renamed CAP_MKFIFO to CAP_MKFIFOAT.
Renamed CAP_MKNODE to CAP_MKNODEAT.
CAP_READ old behaviour:
- Allow pread(2).
- Disallow read(2), readv(2) (if there is no CAP_SEEK).
CAP_READ new behaviour:
- Allow read(2), readv(2).
- Disallow pread(2) (CAP_SEEK was also required).
CAP_WRITE old behaviour:
- Allow pwrite(2).
- Disallow write(2), writev(2) (if there is no CAP_SEEK).
CAP_WRITE new behaviour:
- Allow write(2), writev(2).
- Disallow pwrite(2) (CAP_SEEK was also required).
Added convinient defines:
#define CAP_PREAD (CAP_SEEK | CAP_READ)
#define CAP_PWRITE (CAP_SEEK | CAP_WRITE)
#define CAP_MMAP_R (CAP_MMAP | CAP_SEEK | CAP_READ)
#define CAP_MMAP_W (CAP_MMAP | CAP_SEEK | CAP_WRITE)
#define CAP_MMAP_X (CAP_MMAP | CAP_SEEK | 0x0000000000000008ULL)
#define CAP_MMAP_RW (CAP_MMAP_R | CAP_MMAP_W)
#define CAP_MMAP_RX (CAP_MMAP_R | CAP_MMAP_X)
#define CAP_MMAP_WX (CAP_MMAP_W | CAP_MMAP_X)
#define CAP_MMAP_RWX (CAP_MMAP_R | CAP_MMAP_W | CAP_MMAP_X)
#define CAP_RECV CAP_READ
#define CAP_SEND CAP_WRITE
#define CAP_SOCK_CLIENT \
(CAP_CONNECT | CAP_GETPEERNAME | CAP_GETSOCKNAME | CAP_GETSOCKOPT | \
CAP_PEELOFF | CAP_RECV | CAP_SEND | CAP_SETSOCKOPT | CAP_SHUTDOWN)
#define CAP_SOCK_SERVER \
(CAP_ACCEPT | CAP_BIND | CAP_GETPEERNAME | CAP_GETSOCKNAME | \
CAP_GETSOCKOPT | CAP_LISTEN | CAP_PEELOFF | CAP_RECV | CAP_SEND | \
CAP_SETSOCKOPT | CAP_SHUTDOWN)
Added defines for backward API compatibility:
#define CAP_MAPEXEC CAP_MMAP_X
#define CAP_DELETE CAP_UNLINKAT
#define CAP_MKDIR CAP_MKDIRAT
#define CAP_RMDIR CAP_UNLINKAT
#define CAP_MKFIFO CAP_MKFIFOAT
#define CAP_MKNOD CAP_MKNODAT
#define CAP_SOCK_ALL (CAP_SOCK_CLIENT | CAP_SOCK_SERVER)
Sponsored by: The FreeBSD Foundation
Reviewed by: Christoph Mallon <christoph.mallon@gmx.de>
Many aspects discussed with: rwatson, benl, jonathan
ABI compatibility discussed with: kib
now disables read-ahead. It used to effectively restore the system default
readahead hueristic if it had been changed; a negative value now restores
the default.
Reviewed by: kib
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
Append '__' prefix to the tag of struct oflock, and put it under BSD
namespace. Structure is needed both by libc and kernel, thus cannot be
hidden under #ifdef _KERNEL.
Move a set of non-standard F_* and O_* constants into BSD namespace.
SUSv4 explicitely allows implemenation to pollute F_* and O_* names
after fcntl.h is included, but it costs us nothing to adhere
to the specification if exact POSIX compliance level is requested by
user code.
Change some spaces after #define to tabs.
Noted by and discussed with: bde
MFC after: 1 week
Pass only FEXEC (instead of FREAD|FEXEC) in fgetvp_exec. _fget has to check for
!FWRITE anyway and may as well know about FREAD.
Make _fget code a bit more readable by converting permission checking from if()
to switch(). Assert that correct permission flags are passed.
In collaboration with: kib
Approved by: trasz (mentor)
MFC after: 6 days
X-MFC: with r238220
While here return EBADF for descriptors opened for writing (previously it was ETXTBSY).
Add fgetvp_exec function which performs appropriate checks.
PR: kern/169651
In collaboration with: kib
Approved by: trasz (mentor)
MFC after: 1 week
now fully encapsulates all accesses to f_offset, and extends f_offset
locking to other consumers that need it, in particular, to lseek() and
variants of getdirentries().
Ensure that on 32bit architectures f_offset, which is 64bit quantity,
always read and written under the mtxpool protection. This fixes
apparently easy to trigger race when parallel lseek()s or lseek() and
read/write could destroy file offset.
The already broken ABI emulations, including iBCS and SysV, are not
converted (yet).
Tested by: pho
No objections from: jhb
MFC after: 3 weeks
