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the pointers to the triplet strings are no longer valid.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.
