The datahead structure has an unused padding field that remains
uninitialized. Valgrind prints out a warning for it on querying a
netgroups entry. This is harmless, but is a potential data leak since
it would result in writing out an uninitialized byte to the cache
file. Besides, this happens only when there is a cache miss, so we're
not adding computation to any fast path.
This patch consolidates the code to initialize the header of a dataset
into a single set of functions (one for positive and another for
negative datasets) primarily to reduce repetition of code. The
secondary reason is to simplify Patch 2/2 which fixes the problem of
an uninitialized byte in the header by initializing an unused field in
the structure and hence preventing a possible data leak into the cache
file.
The SELinux team has indicated to me that glibc's SELinux checks
in nscd are not being carried out as they would expect the API
to be used today. They would like to move away from static header
defines for class and permissions and instead use dynamic checks
at runtime that provide an answer which is dependent on the runtime
status of SELinux i.e. more dynamic.
The following patch is a minimal change that moves us forward in
this direction.
It does the following:
* Stop checking for SELinux headers that define NSCD__SHMEMHOST.
Check only for the presence or absence of the library.
* Don't encode the specific SELinux permission constants into a
table at build time, and instead use the symbolic name for the
permission as expected.
* Lookup the "What do we do if we don't know this permission?"
policy and use that if we find SELinux's policy is older than
the glibc policy e.g. we make a request for a permission that
SELinux doesn't know about.
* Lastly, translate the class and permission and then make
the permission check. This is done every time we lookup
a permission, and this is the expected way to use the API.
SELinux will optimize this for us, and we expect the network
latencies to hide these extra library calls.
Tested on x86, x86-64, and via Fedora Rawhide since November 2013.
See:
https://sourceware.org/ml/libc-alpha/2014-04/msg00179.html
This patch defines _STRING_ARCH_unaligned to 0 on default bits/string.h
header to avoid undefined compiler warnings on platforms that do not
define it. It also make adjustments in code where tests checked if macro
existed or not.
Calls to stpcpy from nscd netgroups code will have overlapping source
and destination when all three values in the returned triplet are
non-NULL and in the expected (host,user,domain) order. This is seen
in valgrind as:
==3181== Source and destination overlap in stpcpy(0x19973b48, 0x19973b48)
==3181== at 0x4C2F30A: stpcpy (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==3181== by 0x12567A: addgetnetgrentX (string3.h:111)
==3181== by 0x12722D: addgetnetgrent (netgroupcache.c:665)
==3181== by 0x11114C: nscd_run_worker (connections.c:1338)
==3181== by 0x4E3C102: start_thread (pthread_create.c:309)
==3181== by 0x59B81AC: clone (clone.S:111)
==3181==
Fix this by using memmove instead of stpcpy.
nscd works correctly when the request in innetgr is a wildcard,
i.e. when one or more of host, user or domain parameters is NULL.
However, it does not work when the the triplet in the netgroup
definition has a wildcard. This is easy to reproduce for a triplet
defined as follows:
foonet (,foo,)
Here, an innetgr call that looks like this:
innetgr ("foonet", "foohost", "foo", NULL);
should succeed and so should:
innetgr ("foonet", NULL, "foo", "foodomain");
It does succeed with nscd disabled, but not with nscd enabled. This
fix adds this additional check for all three parts of the triplet so
that it gives the correct result.
[BZ #16758]
* nscd/netgroupcache.c (addinnetgrX): Succeed if triplet has
blank values.
The buffer to query netgroup entries is allocated sufficient space for
the netgroup entries and the key to be appended at the end, but it
sends in an incorrect available length to the NSS netgroup query
functions, resulting in overflow of the buffer in some special cases.
The fix here is to factor in the key length when sending the available
buffer and buffer length to the query functions.
Currently the nscd service is installed in systemd as a simple
service, which means that it is able to handle its own errors and does
not quit. Since nscd does not fit that description, i.e. it can exit
on errors like, say, failing to parse nscd.conf, it should be declared
as forking instead.
Currently, the nscd parent process parses commandline options and
configuration, forks on startup and immediately exits with a success.
If the child process encounters some error after this, it goes
undetected and any services started up after it may have to repeatedly
check to make sure that the nscd service did actually start up and is
serving requests.
To make this process more reliable, I have added a pipe between the
parent and child process, through which the child process sends a
notification to the parent informing it of its status. The parent
waits for this status and once it receives it, exits with the
corresponding exit code. So if the child service sends a success
status (0), the parent exits with a success status. Similarly for
error conditions, the child sends the non-zero status code, which the
parent passes on as the exit code.
This, along with setting the nscd service type to forking in its
systemd configuration file, allows systemd to be certain that the nscd
service is ready and is accepting connections.
The _nss_*_getnetgrent_r query populates the netgroup results in the
allocated buffer and then sets the result triplet to point to strings
in the buffer. This is a problem when the buffer is reallocated since
the pointers to the triplet strings are no longer valid. The pointers
need to be adjusted so that they now point to strings in the
reallocated buffer.
addgetnetgrentX has a buffer which is grown as per the needs of the
requested size either by using alloca or by falling back to malloc if
the size is larger than 1K. There are two problems with the alloca
bits: firstly, it doesn't really extend the buffer since it does not
use the return value of the extend_alloca macro, which is the location
of the reallocated buffer. Due to this the buffer does not actually
extend itself and hence a subsequent write may overwrite stuff on the
stack.
The second problem is more subtle - the buffer growth on the stack is
discontinuous due to block scope local variables. Combine that with
the fact that unlike realloc, extend_alloca does not copy over old
content and you have a situation where the buffer just has garbage in
the space where it should have had data.
This could have been fixed by adding code to copy over old data
whenever we call extend_alloca, but it seems unnecessarily
complicated. This code is not exactly a performance hotspot (it's
called when there is a cache miss, so factors like network lookup or
file reads will dominate over memory allocation/reallocation), so this
premature optimization is unnecessary.
Thanks Brad Hubbard <bhubbard@redhat.com> for his help with debugging
the problem.
Usage output for option --invalidate=TABLE is not helpful without
list of tables. The list is also missing from nscd(8) manual which
made it pretty difficult to know what are the tables.
nscd incorrectly returns a success even when the netgroup in question
is not found and adds a positive result in the cache. this patch
fixes this behaviour by adding a negative lookup entry to cache and
returning an error when the netgroup is not found.
Currently, when a user looks up a netgroup that does not have any
members, nscd goes into an infinite loop trying to find members in the
group. This is because it does not handle cases when getnetgrent
returns an NSS_STATUS_NOTFOUND (which is what it does on empty group).
Fixed to handle this in the same way as NSS_STATUS_RETURN, similar to
what getgrent does by itself.
Autoconf has been deprecating configure.in for quite a long time.
Rename all our configure.in and preconfigure.in files to .ac.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
These prototypes are duplicated in many places. Add a dedicated
header for holding prototypes for program-specific functions to
avoid that.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
We refactor the inotify file checking code and the
database clearing code out of the main_loop_poll and
mail_loop_epoll functions. We document some the related
functions with appropriate comments.
* nscd/grpcache.c (cache_addgr): Rename alloca_used to
dataset_temporary. Track alloca usage into alloca_used.
If dataset is large allocate and release it via malloc/free.
Commit 61653dfb81 added support for
compilers predefining _FORTIFY_SOURCE by adding -U_FORTIFY_SOURCE to
CPPFLAGS for these compilers, but that change doesn't work quite well in
case of nscd: its Makefile sets _FORTIFY_SOURCE using CFLAGS instead of
CPPFLAGS and, thanks to compilation rules defined in Makerules, CPPFLAGS
are passed to compiler after CFLAGS, resulting to a build with
_FORTIFY_SOURCE turned off.
This change implements a more safe method of passing preprocessor and
compiler flags so that no nscd modules could be accidentally forgotten.
2012-05-09 Andreas Jaeger <aj@suse.de>
* nscd/nscd.c (run_modes): Make named enum, reorder so that
default is first entry.
(run_mode): Set type.
(main): Remove informal message about syslog.
(options): Fix typo.
For a better integration of nscd with systemd, we should run nscd not as
daemon but in the foreground. A new --foreground option should be added.
2012-05-09 Alexandre Oliva <aoliva@redhat.com>
Andreas Jaeger <aj@suse.de>
* nscd/nscd.c (go_background): Replaced with...
(run_mode): ... this.
(RUN_FOREGROUND, RUN_DAEMONIZE, RUN_DEBUG): Add.
(options): Add -F --foreground.
(main): Implement it.
(parse_opt): Parse it.
Whenever getaddrinfo needed network interface information it used the
netlink interface to read the information every single time. The
problem is that this information can change at any time.
The patch implements monitoring of the network interfaces through
nscd. If no change is detected the previously read information can
be reused (which is the norm). This timestamp information is also
made available to other processes using the shared memory segment
between nscd and those processes.
nscd can clear caches when certain files change. The list of files
was hardcoded so far and worked for nss_files and nss_dns and those
modules which need no monitoring. nss_db, for instance, has its
own set of files to monitor. Now the NSS modules themselves can
request that certain files are monitored.
When readding entries to the group and services cache and the lookup
is unsuccesful, we tried to write the notfound record. Just don't
do it in this case.
The nscd/*cache.c files contain assert()s, writeall() and sendfileall() calls
that invalidly use together &dataset->resp and total where either dataset or
dataset->head.recsize should be used instead one of the components. In the
writeall() and sendfileall() cases, it is unlikely to matter in practice, but
the assertions can fail sometimes without a proper reason.
The commit 20e498bd removes the pthread_mutex_rdlock() calls, but not the
corresponding pthread_mutex_unlock() calls. Also, the database lock is never
unlocked in one branch of the mempool_alloc() if.
I think unreproducible random assert(dh->usable) crashes in prune_cache() were
caused by this. But an easy way to make nscd threads hang with the broken
locking was.
There are two issues with the forced loop exit in the nscd lookup:
1. the estimate of the entry size isn't pessimistic enough for all
databases, resulting potentially is too early exits
2. the combination of 64-bit process and 32-bit nscd would lead to
rejecting valid records in the database.
The nscd database mapped in processes can change at any time. We
have to be more vigilant when it comes to using that memory. Test
the data entries are valid in their entire size, don't read data
again from memory once we verified it, and make sure the trailing
pointer is not going off the deep end.
Because we are not shutting down the other threads first another
thread might work on a query before the process shuts down. In this
case the now uninitialized libselinux and libaudit might be used.
Just don't free the resources. It's not necessary anyway because
the process is about to terminate.
from definition.
* sysdeps/x86_64/dl-machine.h (elf_machine_rela): Don't define
label if it is not used.
* elf/dl-profile.c (_dl_start_profile): Define real-type variant
of gmon_hist_hdr and gmon_hdr structures and use them.
* elf/dl-load.c (open_verify): Add temporary variable to avoid
warning.
* nscd/nscd_helper.c (get_mapping): Avoid casts to avoid warnings.
* sunrpc/clnt_raw.c (clntraw_private_s): Use union in definition
to avoid cast.
* inet/rexec.c (rexec_af): Make sa2 a union to avoid warnings.
* inet/rcmd.c (rcmd_af): Make from a union of the various needed types
to avoid warnings.
(iruserok_af): Use ss_family instead of casts.
* gmon/gmon.c (write_hist): Define real-type variant of
gmon_hist_hdr structure and use it.
(write_gmon): Likewise for gmon_hdr.
* sysdeps/unix/sysv/linux/readv.c: Avoid declaration of replacement
function if we are not going to define it.
* sysdeps/unix/sysv/linux/writev.c: Likewise.
* inet/inet6_option.c (optin_alloc): Add temporary variable to
avoid warning.
* libio/strfile.h (struct _IO_streambuf): Use correct type and
name of VTable element.
* libio/iovsprintf.c: Avoid casts to avoid warnings.
* libio/iovsscanf.c: Likewise.
* libio/vasprintf.c: Likewise.
* libio/vsnprintf.c: Likewise.
* stdio-common/isoc99_vsscanf.c: Likewise.
* stdlib/strfmon_l.c: Likewise.
* debug/vasprintf_chk.c: Likewise.
* debug/vsnprintf_chk.c: Likewise.
* debug/vsprintf_chk.c: Likewise.
2009-02-13 Ulrich Drepper <drepper@redhat.com>
[BZ #5381]
* nscd/nscd.h: Remove definitions and declarations for mem_in_flight.
Change mempool_alloc prototype.
* nscd/mem.c (gc): Don't handle mem_in_flight.
(mempool_alloc): Third parameter now only indicates whether this is the
first call (to allocate data) or not. If it is, get db rdlock.
Release it on error. Don't handle mem_in_flight.
* nscd/aicache.c (addhstaiX): Mark he parameter as const.
Adjust third parameter of mempool_alloc calls.
Nothing to do here in case mempool_alloc fails.
Avoid local variable shadowing parameter. No need to get db rdlock
before calling cache_add.
* nscd/cache.c (cache_add): Adjust call to mempool_alloc. There is
no mem_in_flight array anymore.
* nscd/connections.c: Remove definition and handling of mem_in_flight.
* nscd/grpcache.c (cache_addgr): Adjust third parameter of
mempool_alloc calls. Mark he parameter as const. Nothing to do here
in case mempool_alloc fails. No need to get db rdlock before calling
cache_add.
* nscd/hstcache.c (cache_addhst): Likewise.
* nscd/initgrcache.c (addinitgroupsX): Likewise.
* nscd/servicescache.c (cache_addserv): Likewise.
* nscd/pwdcache.c (cache_addpw): Likewise. Remove some debugging code.
* elf/ldd.bash.in: Likewise.
* elf/sprof.c: Likewise.
* locale/programs/locale.c: Likewise.
* malloc/memusage.sh: Likewise.
* nss/getent.c: Likewise.
2009-02-06 Joseph Myers <joseph@codesourcery.com>
* debug/pcprofiledump.c (print_version,
argp_program_version_hook): New function.
* elf/ldconfig.c (more_help): New function.
(argp): Use it.
* elf/sln.c (usage): New function.
(main): Support --help and --version.
* malloc/memusagestat.c (print_version): New function.
(argp_program_version_hook): New variable.
* nscd/nscd.c (more_help): New function.
(argp): Use it.
* posix/getconf.c (main): Send --version output to stdout.
Support --help.
* sunrpc/rpc_main.c (usage, options_usage): Take STREAM and STATUS
arguments. All callers changed.
(print_version): New function.
(parseargs): Support --help and --version.
* sunrpc/rpcinfo.c (usage): Take STREAM argument. All callers
changed.
(print_version): New function.
(main): Use getopt_long. Support --help and --version.
* sysdeps/unix/sysv/linux/lddlibc4.c (main): Support --help and
--version.
2009-02-06 Ulrich Drepper <drepper@redhat.com>
* nscd/mem.c (gc): Use alloca_count to get the real stack usage.
* include/alloca.h (alloca_account): Define.
* sysdeps/x86_64/stackinfo.h (stackinfo_get_sp): Define.
(stackinfo_sub_sp): Define.
2009-01-28 Ulrich Drepper <drepper@redhat.com>
[BZ #9741]
* nscd/mem.c (gc): Fix assignment of he_data in case malloc is used.
Reported by Jun'ichi Nomura <j-nomura@ce.jp.nec.com>.
2008-12-03 Petr Baudis <pasky@suse.cz>
[BZ #7067]
* nscd/connections.c (invalidate_cache): Use prune_run_lock
instead of prune_lock.
(nscd_run_prune): Before calling prune_cache, take prune_run_lock.
* nscd/nscd.h (database_dyn): Add prune_run_cache.
__ASSUME_PACCEPT, __ASSUME_IN_NONBLOCK, and __ASSUME_PACCEPT if
appropriate.
* nscd/connections.c: Avoid fcntl calls to set close-on-exec flag and
non-blocking mode by using socket, paccept, and inotify_init1.
fields.
* nscd/connections.c (inotify_fd): New variable.
(nscd_init): Try to open an inotify descriptor.
If successful, watch files for databases using inotify instead of
having prune threads stat the files.
(nscd_run_prune): Recognize clear_cache flag being set and call
prune_cache appropriately.
(main_loop_poll): Add inotify descriptor to wait set and handle the
reported changes.
(main_loop_epoll): Likewise.
* nscd/cache.c (prune_cache): Don't stat files for databases if
inotify is used.
* sysdeps/unix/sysv/linux/Makefile [subdir=nscd]
(CFLAGS-connections.c): Add -DHAVE_INOTIFY.
instead of portstr to nscd_getserv_r. Patch by
Roman Kagan <rkagan@mail.ru>.
2008-06-03 Jakub Jelinek <jakub@redhat.com>
* nscd/nscd_getserv_r.c (__nscd_getservbyport_r): Pass cp
instead of portstr to nscd_getserv_r. Patch by
Roman Kagan <rkagan@mail.ru>.
whether this is in response of a cache refill. Check alignment
of package data. Revamp waking of pruning thread.
(prune_cache): Small optimization.
* nscd/nscd.h: Adjust cache_add prototypes.
* nscd/aicache.c: Adjust cache_add calls.
* nscd/grpcache.c: Likewise.
* nscd/hstcache.c: Likewise.
* nscd/initgrcache.c: Likewise.
* nscd/pwdcache.c: Likewise.
* nscd/servicescache.c: Likewise.
* nscd/connections.c (restart): Really disable cache use before
exec attempt. If it fails, reenable cache.
(nscd_run_prune): Initialize wakeup_time. After wakeup, set wakeup
time to max to be able to notice concurrent cache additions. Unlock
prune_lock while performing gc. Afterwards compute wakeup time with
current wakeup_time value in mind.
is the first use of the record, mark it as unusable.
* nscd/aicache.c: Don't touch the dataset after cache_add returns
reporting a failure.
* nscd/grpcache.c: Likewise
* nscd/hstcache.c: Likewise.
* nscd/initgrcache.c: Likewise.
* nscd/pwdcache.c: Likewise.
* nscd/servicecache.c: Likewise.
prototypes.
* include/arpa/nameser_compat.h: Define T_UNSPEC.
* nis/Versions (libnss_nis): Export _nss_nis_gethostbyname4_r.
(libnss_nisplus): Export _nss_nisplus_gethostbyname4_r.
* nis/nss_nis/nis-hosts.c (LINE_PARSER): Change to also handle
af==AF_UNSPEC.
(_nss_nis_gethostbyname4_r): New function.
* nis/nss_nisplus/nisplus-hosts.c (_nss_nisplus_parse_hostent):
Change to also handle af==AF_UNSPEC.
(get_tablename): New function. Use it to avoid duplication.
(_nss_nisplus_gethostbyname4_r): New function.
* nscd/aicache.c (addhstaiX): Use gethostbyname4_r function is
available.
* nss/Versions (libnss_files): Export _nss_files_gethostbyname4_r.
* nss/nss.h: Define struct gaih_addrtuple.
* nss/nss_files/files-hosts.c (LINE_PARSER): Change to also handle
af==AF_UNSPEC.
(_nss_files_gethostbyname4_r): New function.
* resolv/Versions (libnss_dns): Export _nss_dns_gethostbyname4_r.
* resolv/gethnmaddr.c: Adjust __libc_res_nsearch and __libc_res_nquery
calls.
* resolv/res_query.c (__libc_res_nquery): Take two additional
parameters for second answer buffer. Handle type=T_UNSPEC to mean
look up IPv4 and IPv6.
Change all callers.
* resolv/res_send.c (__libc_res_nsend): Take five aditional parameters
for an additional query and answer buffer. Pass to send_vc and
send_dg.
(send_vc): Send possibly two requests and receive two answers.
(send_dg): Likewise.
* resolv/nss_dns/dns-host.c: Adjust calls to __libc_res_nsearch and
__libc_res_nquery.
(_nss_dns_gethostbyname4_r): New function.
(gaih_getanswer_slice): Likewise.
(gaih_getanswer): Likewise.
* resolv/nss_dns/dns-canon.c (_nss_dns_getcanonname_r): Adjust
__libc_res_nquery call.
* resolv/nss_dns/dns-network.c (_nss_dns_getnetbyaddr_r): Likewise.
(_nss_dns_getnetbyname_r): Adjust __libc_res_nsearch call.
* sysdeps/posix/getaddrinfo.c: Use gethostbyname4_r function is
available.
2008-04-15 Ulrich Drepper <drepper@redhat.com>
[BZ #5209]
* sysdeps/unix/sysv/linux/times.c: New file.
[BZ #5381]
* nscd/nscd.h: Define enum in_flight, mem_in_flight, and
mem_in_flight_list variables. Add new parameter to mempool_alloc
prototype.
* nscd/mem.c (mempool_alloc): Take additional parameter. Initialize
appropriate mem_in_flight element.
(gc): Take allocations which have not yet been committed to the
database into account.
* nscd/cache.c (cache_add): Add new parameter to mempool_alloc call.
Reset mem_in_flight before returning.
* nscd/connections.c (nscd_run_worker): Initialize mem_in_flight and
cue it up in mem_in_flight_list.
* nscd/aicache.c: Adjust mempool_alloc call.
* nscd/grpcache.c: Likewise.
* nscd/hstcache.c: Likewise.
* nscd/initgrcache.c: Likewise.
* nscd/pwdcache.c: Likewise.
* nscd/servicescache.c: Likewise.
* nscd/Makefile (nscd-flags): Until ld is fixed, use -fpic instead
of -fpie.
* nscd/connections.c (handle_request): Provide better error message
in case SELinux forbids the service.
* version.h (VERSION): Bump to 2.8.90.
