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author | Patrick J Volkerding <volkerdi@slackware.com> | 2018-05-28 19:12:29 +0000 |
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committer | Eric Hameleers <alien@slackware.com> | 2018-05-31 23:39:35 +0200 |
commit | 646a5c1cbfd95873950a87b5f75d52073a967023 (patch) | |
tree | b8b8d2ab3b0d432ea69ad1a64d1c789649d65020 /source/a/shadow/shadow.CVE-2017-2616.diff | |
parent | d31c50870d0bee042ce660e445c9294a59a3a65b (diff) | |
download | current-646a5c1cbfd95873950a87b5f75d52073a967023.tar.gz current-646a5c1cbfd95873950a87b5f75d52073a967023.tar.xz |
Mon May 28 19:12:29 UTC 201820180528191229
a/pkgtools-15.0-noarch-13.txz: Rebuilt.
installpkg: default line length for --terselength is the number of columns.
removepkg: added --terse mode.
upgradepkg: default line length for --terselength is the number of columns.
upgradepkg: accept -option in addition to --option.
ap/vim-8.1.0026-x86_64-1.txz: Upgraded.
d/bison-3.0.5-x86_64-1.txz: Upgraded.
e/emacs-26.1-x86_64-1.txz: Upgraded.
kde/kopete-4.14.3-x86_64-8.txz: Rebuilt.
Recompiled against libidn-1.35.
n/conntrack-tools-1.4.5-x86_64-1.txz: Upgraded.
n/libnetfilter_conntrack-1.0.7-x86_64-1.txz: Upgraded.
n/libnftnl-1.1.0-x86_64-1.txz: Upgraded.
n/links-2.16-x86_64-2.txz: Rebuilt.
Rebuilt to enable X driver for -g mode.
n/lynx-2.8.9dev.19-x86_64-1.txz: Upgraded.
n/nftables-0.8.5-x86_64-1.txz: Upgraded.
n/p11-kit-0.23.11-x86_64-1.txz: Upgraded.
n/ulogd-2.0.7-x86_64-1.txz: Upgraded.
n/whois-5.3.1-x86_64-1.txz: Upgraded.
xap/network-manager-applet-1.8.12-x86_64-1.txz: Upgraded.
xap/vim-gvim-8.1.0026-x86_64-1.txz: Upgraded.
Diffstat (limited to 'source/a/shadow/shadow.CVE-2017-2616.diff')
-rw-r--r-- | source/a/shadow/shadow.CVE-2017-2616.diff | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/source/a/shadow/shadow.CVE-2017-2616.diff b/source/a/shadow/shadow.CVE-2017-2616.diff new file mode 100644 index 000000000..4a5c44222 --- /dev/null +++ b/source/a/shadow/shadow.CVE-2017-2616.diff @@ -0,0 +1,55 @@ +su: properly clear child PID + +If su is compiled with PAM support, it is possible for any local user +to send SIGKILL to other processes with root privileges. There are +only two conditions. First, the user must be able to perform su with +a successful login. This does NOT have to be the root user, even using +su with the same id is enough, e.g. "su $(whoami)". Second, SIGKILL +can only be sent to processes which were executed after the su process. +It is not possible to send SIGKILL to processes which were already +running. I consider this as a security vulnerability, because I was +able to write a proof of concept which unlocked a screen saver of +another user this way. + +diff --git a/src/su.c b/src/su.c +index f20d230..d86aa86 100644 +--- a/src/su.c ++++ b/src/su.c +@@ -379,11 +379,13 @@ static void prepare_pam_close_session (void) + /* wake child when resumed */ + kill (pid, SIGCONT); + stop = false; ++ } else { ++ pid_child = 0; + } + } while (!stop); + } + +- if (0 != caught) { ++ if (0 != caught && 0 != pid_child) { + (void) fputs ("\n", stderr); + (void) fputs (_("Session terminated, terminating shell..."), + stderr); +@@ -393,9 +395,22 @@ static void prepare_pam_close_session (void) + snprintf (wait_msg, sizeof wait_msg, _(" ...waiting for child to terminate.\n")); + + (void) signal (SIGALRM, kill_child); ++ (void) signal (SIGCHLD, catch_signals); + (void) alarm (2); + +- (void) wait (&status); ++ sigemptyset (&ourset); ++ if ((sigaddset (&ourset, SIGALRM) != 0) ++ || (sigprocmask (SIG_BLOCK, &ourset, NULL) != 0)) { ++ fprintf (stderr, _("%s: signal masking malfunction\n"), Prog); ++ kill_child (0); ++ } else { ++ while (0 == waitpid (pid_child, &status, WNOHANG)) { ++ sigsuspend (&ourset); ++ } ++ pid_child = 0; ++ (void) sigprocmask (SIG_UNBLOCK, &ourset, NULL); ++ } ++ + (void) fputs (_(" ...terminated.\n"), stderr); + } |