linux_getdents uses VOP_READDIR( ..., &ncookies, &cookies ) instead of
VOP_READDIR( ..., NULL, NULL ) because it seems to need the offsets for
linux_dirent and sizeof(dirent) != sizeof(linux_dirent)...
PR: 29467
Submitted by: Michael Reifenberger <root@nihil.plaut.de>
Reviewed by: phk
as there are now "unusual" protection properties to Pmem that differ
from the other files. While I'm at it, introduce proc locking for
the other files, which was previously present only in the Pmem case.
Obtained from: TrustedBSD Project
and so special-casing was introduced to provide extra procfs privilege
to the kmem group. With the advent of non-setgid kmem ps, this code
is no longer required, and in fact, can is potentially harmful as it
allocates privilege to a gid that is increasingly less meaningful.
Knowledge of specific gid's in kernel is also generally bad precedent,
as the kernel security policy doesn't distinguish gid's specifically,
only uid 0.
This commit removes reference to kmem in procfs, both in terms of
access control decisions, and the applying of gid kmem to the
/proc/*/mem file, simplifying the associated code considerably.
Processes are still permitted to access the mem file based on
the debugging policy, so ps -e still works fine for normal
processes and use.
Reviewed by: tmm
Obtained from: TrustedBSD Project
The p_can(...) construct was a premature (and, it turns out,
awkward) abstraction. The individual calls to p_canxxx() better
reflect differences between the inter-process authorization checks,
such as differing checks based on the type of signal. This has
a side effect of improving code readability.
o Replace direct credential authorization checks in ktrace() with
invocation of p_candebug(), while maintaining the special case
check of KTR_ROOT. This allows ktrace() to "play more nicely"
with new mandatory access control schemes, as well as making its
authorization checks consistent with other "debugging class"
checks.
o Eliminate "privused" construct for p_can*() calls which allowed the
caller to determine if privilege was required for successful
evaluation of the access control check. This primitive is currently
unused, and as such, serves only to complicate the API.
Approved by: ({procfs,linprocfs} changes) des
Obtained from: TrustedBSD Project
(this commit is just the first stage). Also add various GIANT_ macros to
formalize the removal of Giant, making it easy to test in a more piecemeal
fashion. These macros will allow us to test fine-grained locks to a degree
before removing Giant, and also after, and to remove Giant in a piecemeal
fashion via sysctl's on those subsystems which the authors believe can
operate without Giant.
Replace the a.out emulation of 'struct linker_set' with something
a little more flexible. <sys/linker_set.h> now provides macros for
accessing elements and completely hides the implementation.
The linker_set.h macros have been on the back burner in various
forms since 1998 and has ideas and code from Mike Smith (SET_FOREACH()),
John Polstra (ELF clue) and myself (cleaned up API and the conversion
of the rest of the kernel to use it).
The macros declare a strongly typed set. They return elements with the
type that you declare the set with, rather than a generic void *.
For ELF, we use the magic ld symbols (__start_<setname> and
__stop_<setname>). Thanks to Richard Henderson <rth@redhat.com> for the
trick about how to force ld to provide them for kld's.
For a.out, we use the old linker_set struct.
NOTE: the item lists are no longer null terminated. This is why
the code impact is high in certain areas.
The runtime linker has a new method to find the linker set
boundaries depending on which backend format is in use.
linker sets are still module/kld unfriendly and should never be used
for anything that may be modular one day.
Reviewed by: eivind
not behaving correctly. Fix by attaching to the correct socket.
Also call so{rw}wakeup in addition to the fifo wakeup, so that any
kqfilters attached to the socket buffer get poked.
Only tun0 -> tun32767 may now be opened as struct ifnet's if_unit
is a short.
It's now possible to open /dev/tun and get a handle back for an available
tun device (use devname to find out what you got).
The implementation uses rman by popular demand (and against my judgement)
to track opened devices and uses the new dev_depends() to ensure that
all make_dev()d devices go away before the module is unloaded.
Reviewed by: phk
dev_t. The dev_depends(dev_t, dev_t) function is for tying them
to each other.
When destroy_dev() is called on a dev_t, all dev_t's depending
on it will also be destroyed (depth first order).
Rewrite the make_dev_alias() to use this dependency facility.
kern/subr_disk.c:
Make the disk mini-layer use dependencies to make sure all
relevant dev_t's are removed when the disk disappears.
Make the disk mini-layer precreate some magic sub devices
which the disk/slice/label code expects to be there.
kern/subr_disklabel.c:
Remove some now unneeded variables.
kern/subr_diskmbr.c:
Remove some ancient, commented out code.
kern/subr_diskslice.c:
Minor cleanup. Use name from dev_t instead of dsname()
real uid, saved uid, real gid, and saved gid to ucred, as well as the
pcred->pc_uidinfo, which was associated with the real uid, only rename
it to cr_ruidinfo so as not to conflict with cr_uidinfo, which
corresponds to the effective uid.
o Remove p_cred from struct proc; add p_ucred to struct proc, replacing
original macro that pointed.
p->p_ucred to p->p_cred->pc_ucred.
o Universally update code so that it makes use of ucred instead of pcred,
p->p_ucred instead of p->p_pcred, cr_ruidinfo instead of p_uidinfo,
cr_{r,sv}{u,g}id instead of p_*, etc.
o Remove pcred0 and its initialization from init_main.c; initialize
cr_ruidinfo there.
o Restruction many credential modification chunks to always crdup while
we figure out locking and optimizations; generally speaking, this
means moving to a structure like this:
newcred = crdup(oldcred);
...
p->p_ucred = newcred;
crfree(oldcred);
It's not race-free, but better than nothing. There are also races
in sys_process.c, all inter-process authorization, fork, exec, and
exit.
o Remove sigio->sio_ruid since sigio->sio_ucred now contains the ruid;
remove comments indicating that the old arrangement was a problem.
o Restructure exec1() a little to use newcred/oldcred arrangement, and
use improved uid management primitives.
o Clean up exit1() so as to do less work in credential cleanup due to
pcred removal.
o Clean up fork1() so as to do less work in credential cleanup and
allocation.
o Clean up ktrcanset() to take into account changes, and move to using
suser_xxx() instead of performing a direct uid==0 comparision.
o Improve commenting in various kern_prot.c credential modification
calls to better document current behavior. In a couple of places,
current behavior is a little questionable and we need to check
POSIX.1 to make sure it's "right". More commenting work still
remains to be done.
o Update credential management calls, such as crfree(), to take into
account new ruidinfo reference.
o Modify or add the following uid and gid helper routines:
change_euid()
change_egid()
change_ruid()
change_rgid()
change_svuid()
change_svgid()
In each case, the call now acts on a credential not a process, and as
such no longer requires more complicated process locking/etc. They
now assume the caller will do any necessary allocation of an
exclusive credential reference. Each is commented to document its
reference requirements.
o CANSIGIO() is simplified to require only credentials, not processes
and pcreds.
o Remove lots of (p_pcred==NULL) checks.
o Add an XXX to authorization code in nfs_lock.c, since it's
questionable, and needs to be considered carefully.
o Simplify posix4 authorization code to require only credentials, not
processes and pcreds. Note that this authorization, as well as
CANSIGIO(), needs to be updated to use the p_cansignal() and
p_cansched() centralized authorization routines, as they currently
do not take into account some desirable restrictions that are handled
by the centralized routines, as well as being inconsistent with other
similar authorization instances.
o Update libkvm to take these changes into account.
Obtained from: TrustedBSD Project
Reviewed by: green, bde, jhb, freebsd-arch, freebsd-audit
