[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Bug#1036811: marked as done (bullseye-pu: package ncurses/6.2+20201114-2+deb11u2)

Your message dated Sat, 07 Oct 2023 12:41:28 +0100
with message-id <84bb5ff8312f749ebe536897993782bf35aa1977.camel@adam-barratt.org.uk>
and subject line Closing opu requests for updates included in 11.8
has caused the Debian Bug report #1036811,
regarding bullseye-pu: package ncurses/6.2+20201114-2+deb11u2
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
misconfiguration somewhere. Please contact owner@bugs.debian.org
immediately.)


-- 
1036811: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1036811
Debian Bug Tracking System
Contact owner@bugs.debian.org with problems
--- Begin Message --- 
Package: release.debian.org
Severity: normal
Tags: bullseye d-i
User: release.debian.org@packages.debian.org
Usertags: pu
X-Debbugs-Cc: ncurses@packages.debian.org, debian-boot@lists.debian.org
Control: affects -1 + src:ncurses

I would like to address CVE-2023-29491[1] aka bug #1034372[2] in
Bullseye.  The changes are the same as in version 6.4-3 (see
#1035351[3]), except that there is no need to patch configure.in this
time.

[ Reason ]
Various memory corruption bugs exist when loading specifically crafted
terminfo database files.  This is a security problem in programs running
with elevated privileges, as users are allowed to provide their own
terminfo files under ${HOME}/.terminfo or via the TERMINFO or
TERMINFO_DIRS environment variables.

Backporting the upstream fixes would be too intrusive (and has not been
attempted in Bookworm either), but via a configure option it is possible
to prevent setuid/setgid programs from loading custom terminfo files
supplied by the user, after which the bugs are no longer security
relevant.

[ Impact ]
Local users could try privilege escalations in setuid/setgid programs
linked to the tinfo library.  How easily those can be achieved probably
depends on the program.

[ Tests ]
No automatic tests exist.  I have manually verified that programs can no
longer use custom terminfo files if their effective UID or GID differs
from the real one.  Also I have verified that the terminfo database in
the ncurses-{base,term} packages is unchanged from 6.2+20201114-2+deb11u2.

[ Risks ]
Users who are relying on their own terminfo files under
${HOME}/.terminfo can no longer use them in setuid/setgid programs and
will have to work around that, e.g. by changing their TERM environment
variable, using a different terminal emulator or asking their sysadmin
for help.

On my systems I did not find any setuid binaries linked to the tinfo
library, but some setgid games in the bsdgames package.

[ Checklist ]
  [x] *all* changes are documented in the d/changelog
  [x] I reviewed all changes and I approve them
  [x] attach debdiff against the package in (old)stable
  [x] the issue is verified as fixed in unstable

I have slightly edited the debdiff to exclude spurious changes to the
debian/lib{32,64}tinfo6.symbols files, as these are just symlinks to
libtinfo6.symbols.  See devscripts bug #773762[4].

[ Other info ]
Since ncurses produces a udeb I have CC'ed debian-boot and tagged the
bug accordingly.  The screen binary in the screen-udeb package is
actually affected by the change, as it is installed setgid utmp.  This
should not really matter though, since the terminfo files in the
di-utils-terminfo package are installed in the standard place under
/lib/terminfo.

Thanks for consideration.

Cheers,
       Sven


1. https://security-tracker.debian.org/tracker/CVE-2023-29491
2. https://bugs.debian.org/1034372
3. https://bugs.debian.org/1035351
4. https://bugs.debian.org/773762


diff -Nru ncurses-6.2+20201114/debian/changelog ncurses-6.2+20201114/debian/changelog
--- ncurses-6.2+20201114/debian/changelog	2023-02-08 20:16:03.000000000 +0100
+++ ncurses-6.2+20201114/debian/changelog	2023-05-26 20:31:08.000000000 +0200
@@ -1,3 +1,17 @@
+ncurses (6.2+20201114-2+deb11u2) bullseye; urgency=medium
+
+  * Configure with "--disable-root-environ" to disallow loading of
+    custom terminfo entries in setuid/setgid programs, mitigating the
+    impact of CVE-2023-29491 (see #1034372).
+    - Update the symbols files for the newly exported symbol
+      _nc_env_access.
+    - New patch debian-env-access.diff, changing the behavior of the
+      "--disable-root-environ" configure option to not restrict programs
+      run by the superuser, equivalent to the "--disable-setuid-environ"
+      option introduced in the 20230423 patchlevel.
+
+ -- Sven Joachim <svenjoac@gmx.de>  Fri, 26 May 2023 20:31:08 +0200
+
 ncurses (6.2+20201114-2+deb11u1) bullseye; urgency=medium
 
   * New patch CVE-2022-29458.diff: add a limit-check to guard against
diff -Nru ncurses-6.2+20201114/debian/libtinfo5.symbols ncurses-6.2+20201114/debian/libtinfo5.symbols
--- ncurses-6.2+20201114/debian/libtinfo5.symbols	2021-01-01 10:31:15.000000000 +0100
+++ ncurses-6.2+20201114/debian/libtinfo5.symbols	2023-05-26 19:46:17.000000000 +0200
@@ -95,6 +95,7 @@
  _nc_curr_col@NCURSES_TINFO_5.0.19991023 6
  _nc_curr_line@NCURSES_TINFO_5.0.19991023 6
  _nc_doalloc@NCURSES_TINFO_5.0.19991023 6
+ _nc_env_access@NCURSES_TINFO_5.2.20001021 6.2+20201114-2+deb11u2~
  _nc_err_abort@NCURSES_TINFO_5.0.19991023 6
  _nc_fallback@NCURSES_TINFO_5.0.19991023 6
  _nc_find_entry@NCURSES_TINFO_5.0.19991023 6
diff -Nru ncurses-6.2+20201114/debian/libtinfo6.symbols ncurses-6.2+20201114/debian/libtinfo6.symbols
--- ncurses-6.2+20201114/debian/libtinfo6.symbols	2021-01-01 10:31:15.000000000 +0100
+++ ncurses-6.2+20201114/debian/libtinfo6.symbols	2023-05-26 19:46:17.000000000 +0200
@@ -94,6 +94,7 @@
  _nc_curr_col@NCURSES6_TINFO_5.0.19991023 6
  _nc_curr_line@NCURSES6_TINFO_5.0.19991023 6
  _nc_doalloc@NCURSES6_TINFO_5.0.19991023 6
+ _nc_env_access@NCURSES6_TINFO_5.2.20001021 6.2+20201114-2+deb11u2~
  _nc_err_abort@NCURSES6_TINFO_5.0.19991023 6
  _nc_export_termtype2@NCURSES6_TINFO_6.1.20171230 6.1
  _nc_fallback2@NCURSES6_TINFO_6.1.20171230 6.1
diff -Nru ncurses-6.2+20201114/debian/patches/debian-env-access.diff ncurses-6.2+20201114/debian/patches/debian-env-access.diff
--- ncurses-6.2+20201114/debian/patches/debian-env-access.diff	1970-01-01 01:00:00.000000000 +0100
+++ ncurses-6.2+20201114/debian/patches/debian-env-access.diff	2023-05-26 19:45:39.000000000 +0200
@@ -0,0 +1,27 @@
+Author: Sven Joachim <svenjoac@gmx.de>
+Description: Change the --disable-root-environ configure option behavior
+ By default, the --disable-root-environ option forbids program run by
+ the superuser to load custom terminfo entries.  This patch changes
+ that to only restrict programs running with elevated privileges,
+ matching the behavior of the --disable-setuid-environ option
+ introduced in the 20230423 upstream patchlevel.
+Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1034372#29
+Bug: https://lists.gnu.org/archive/html/bug-ncurses/2023-04/msg00018.html
+Forwarded: not-needed
+Last-Update: 2023-05-26
+
+---
+ ncurses/tinfo/access.c |    3 +--
+ 1 file changed, 1 insertion(+), 2 deletions(-)
+
+--- a/ncurses/tinfo/access.c
++++ b/ncurses/tinfo/access.c
+@@ -185,7 +185,6 @@ _nc_env_access(void)
+ 	|| getgid() != getegid())
+ 	return FALSE;
+ #endif
+-    /* ...finally, disallow root */
+-    return (getuid() != ROOT_UID) && (geteuid() != ROOT_UID);
++    return TRUE;
+ }
+ #endif
diff -Nru ncurses-6.2+20201114/debian/patches/series ncurses-6.2+20201114/debian/patches/series
--- ncurses-6.2+20201114/debian/patches/series	2023-01-28 12:16:18.000000000 +0100
+++ ncurses-6.2+20201114/debian/patches/series	2023-05-26 19:45:13.000000000 +0200
@@ -6,3 +6,4 @@
 03-debian-ncursesconfig-omit-L.diff
 CVE-2022-29458.diff
 fix_crash_on_very_long_tc-use_clause.diff
+debian-env-access.diff
diff -Nru ncurses-6.2+20201114/debian/rules ncurses-6.2+20201114/debian/rules
--- ncurses-6.2+20201114/debian/rules	2021-01-01 10:31:15.000000000 +0100
+++ ncurses-6.2+20201114/debian/rules	2023-05-26 19:46:17.000000000 +0200
@@ -141,6 +141,7 @@
 		--without-progs \
 		$(with_mouse) \
 		--enable-symlinks \
+		--disable-root-environ \
 		--disable-termcap \
 		--with-default-terminfo-dir=/etc/terminfo \
 		--with-terminfo-dirs="/etc/terminfo:/lib/terminfo:/usr/share/terminfo" \

Attachment: signature.asc
Description: PGP signature


--- End Message ---
--- Begin Message --- 
Package: release.debian.org
Version: 11.8

Hi,

The updates referred to by each of these requests were included in
today's 11.8 bullseye point release.

Regards,

Adam

--- End Message ---
Reply to: