src/lib/libc/gen/getpwent.c, branch releng/12.4

libc/nss: Restore iterator state when doing passwd/group lookups

2021-02-20T16:35:32Z

The getpwent(3) and getgrent(3) implementations maintain some internal iterator state. Interleaved calls to functions which do passwd/group lookups using a key, such as getpwnam(3), would in some cases clobber this state, causing a subsequent getpwent() or getgrent() call to restart iteration from the beginning of the database or to terminate early. This is particularly troublesome in programming environments where execution of green threads is interleaved within a single OS thread. Take care to restore any iterator state following a keyed lookup. The "files" provider for the passwd database was already handling this correctly, but "compat" was not, and both providers had this problem when accessing the group database. PR: 252094 Submitted by: Viktor Dukhovni (cherry picked from commit 5619d49e07d3942e438f3d06269f3c1c466cf5b7)

MFC r365910:

2020-11-26T23:34:02Z

fix integer underflow in getgrnam_r and getpwnam_r Sometimes nscd(8) will return a 1-byte buffer for a nonexistent entry. This triggered an integer underflow in grp_unmarshal_func, causing getgrnam_r to return ERANGE instead of 0. Fix the user's buffer size check, and add a correct check for a too-small nscd buffer. PR: 248932 Event: September 2020 Bugathon Reviewed by: markj Sponsored by: Axcient Differential Revision: https://reviews.freebsd.org/D26204

MFC r359978:

2020-04-27T23:47:40Z

Fix -Wvoid-pointer-to-enum-cast warnings. This pattern is used in callbacks with void * data arguments and seems both relatively uncommon and relatively harmless. Silence the warning by casting through uintptr_t. This warning is on by default in Clang 11. Reviewed by: arichardson Obtained from: CheriBSD (partial) Sponsored by: DARPA Differential Revision: https://reviews.freebsd.org/D24425

Make pw_scan(3) more compatible with getpwent(3) et. al. when processing

2018-07-26T18:34:38Z

data from /etc/passwd rather than /etc/master.passwd. The libc getpwent(3) and related functions automatically read master.passwd when run by root, or passwd when run by a non-root user. When run by non- root, getpwent() copes with the missing data by setting the corresponding fields in the passwd struct to known values (zeroes for numbers, or a pointer to an empty string for literals). When libutil's pw_scan(3) was used to parse a line without the root-accessible data, it was leaving garbage in the corresponding fields. These changes rename the static pw_init() function used by getpwent() and friends to __pw_initpwd(), and move it into pw_scan.c so that common init code can be shared between libc and libutil. pw_scan(3) now calls __pw_initpwd() before __pw_scan(), just like the getpwent() family does, so that reading an arbitrary passwd file in either format and parsing it with pw_scan(3) returns the same results as getpwent(3) would. This also adds a new pw_initpwd(3) function to libutil, so that code which creates passwd structs from scratch in some manner that doesn't involve pw_scan() can initialize the struct to the values expected by lots of existing code, which doesn't expect to encounter NULL pointers or garbage values in some fields.

libc: further adoption of SPDX licensing ID tags.

2017-11-25T17:12:48Z

Mainly focus on files that use BSD 2-Clause license, however the tool I was using mis-identified many licenses so this was mostly a manual - error prone - task. 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.

libc: make some more use of the nitems() macro.

2016-04-16T17:52:00Z

We have an nitems() macro in the header that is convenient to re-use as it makes things easier to read. Given that it is available already without adding additional headers and other parts of libc already use it, extend a bit more its use.

Fix compiling with gcc [4.2.1] after r287797 when MK_HESOID == no and

2015-10-25T07:42:56Z

MK_NIS == no by converting `i` back to an int, and instead cast the loop comparison to `int` The loop comparison is iterating the len(ns_dtab)-1, because the last element is the sentinel tuple { NULL, NULL, NULL, }, so when both HESOID and NIS are off, len(ns_dtab)-1 == 1 - 1 == 0, and the loop is skipped because the expression is tautologically false While here, convert `(sizeof(x) / sizeof(x[0]))` to `nitems(x)` Tested with: clang 3.7.0, gcc 4.2.1, and gcc 4.9.4 [*] with MK_NIS={no,yes} and by running bash -lc 'id -u && id -g && id' * gcc 4.9.4 needs another patch in order for the compile to succeed with -Werror with lib/libc/gen/getgrent.c Reported by: jhibbits

Use unsigned variables in a few places.

2015-09-14T18:59:01Z

Eliminates gcc 4.9 warnings.

compat_passwd(): yet another uninitialized access to stayopen.

2015-03-06T22:22:57Z

CID: 1018731

Fix small memleaks in nis_passwd() and nis_group().

2015-02-20T01:02:32Z

These only occur upon error. Code Review: https://reviews.freebsd.org/D1849 Reviewed by: delphij CID: 1016715 CID: 1016717