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[PATCH] nisplus: Correct pwent parsing issue and resulting compilation error
- From: "Maciej W. Rozycki" <macro at mips dot com>
- To: <libc-alpha at sourceware dot org>
- Date: Mon, 18 Jun 2018 16:10:27 +0100
- Subject: [PATCH] nisplus: Correct pwent parsing issue and resulting compilation error
Copy and null-terminate NIS+ password file UID and GID entries whose
length is non-zero rather than zero, fixing a bug and a compilation
issue causing an error with GCC 8:
nss_nisplus/nisplus-parser.c: In function '_nss_nisplus_parse_pwent':
nss_nisplus/nisplus-parser.c:90:7: error: 'strncpy' destination unchanged after copying no bytes [-Werror=stringop-truncation]
strncpy (first_unused, numstr, len);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
nss_nisplus/nisplus-parser.c:106:7: error: 'strncpy' destination unchanged after copying no bytes [-Werror=stringop-truncation]
strncpy (first_unused, numstr, len);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
introduced with commit ac05397075f6:
commit ac05397075f621cfdbe1db527c96167a58b6d18e
Author: Ulrich Drepper <drepper@redhat.com>
Date: Sun Apr 30 07:01:26 2006 +0000
* nis/nss_nisplus/nisplus-parser.c: Minor optimizations and
cleanups. Avoid copying data if it can be used in the old place.
(no mailing list reference available). Obviously regardless of the
recently added compiler diagnostics causing a build error this code has
been long non-functional, so I guess NIS+ servers have been supplying
strings that have already been null-terminated. Which in turn made it
unnecessary to make a null-terminated copy, masking this bug.
* nis/nss_nisplus/nisplus-parser.c (_nss_nisplus_parse_pwent):
Copy and null-terminate entries whose length is non-zero rather
than zero.
---
Hi,
No issues seen in `mips-linux-gnu' o32 testing. OK to apply?
Also this may have to be backported and security implications evaluated.
Maciej
---
nis/nss_nisplus/nisplus-parser.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
glibc-nisplus-parse-pwent-len.diff
Index: glibc/nis/nss_nisplus/nisplus-parser.c
===================================================================
--- glibc.orig/nis/nss_nisplus/nisplus-parser.c 2018-02-14 14:57:00.000000000 +0000
+++ glibc/nis/nss_nisplus/nisplus-parser.c 2018-06-16 21:47:29.071633078 +0100
@@ -82,7 +82,7 @@ _nss_nisplus_parse_pwent (nis_result *re
char *numstr = NISOBJVAL (2, obj);
len = NISOBJLEN (2, obj);
- if (len == 0 && numstr[len - 1] != '\0')
+ if (len != 0 && numstr[len - 1] != '\0')
{
if (len >= room_left)
goto no_more_room;
@@ -98,7 +98,7 @@ _nss_nisplus_parse_pwent (nis_result *re
numstr = NISOBJVAL (3, obj);
len = NISOBJLEN (3, obj);
- if (len == 0 && numstr[len - 1] != '\0')
+ if (len != 0 && numstr[len - 1] != '\0')
{
if (len >= room_left)
goto no_more_room;