diff options
author | Andrej Valek <andrej.valek@siemens.com> | 2018-07-24 13:08:29 +0200 |
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committer | Richard Purdie <richard.purdie@linuxfoundation.org> | 2018-10-10 13:26:53 +0100 |
commit | eec9169658733335c6f8251b5122706fa8ab467d (patch) | |
tree | ad032d56886b586b272ca698e9a67746698f3ab9 | |
parent | 9aed83eb8694a0bd409a6a2481bfd2a1b98919e1 (diff) | |
download | openembedded-core-contrib-eec9169658733335c6f8251b5122706fa8ab467d.tar.gz |
shadow: fix CVE-2017-2616
(From OE-Core rev: 94a1e2794df15f0f2cb62ae030cd81e6c0798b1f)
(From OE-Core rev: 8894c70ae5a44974f74434d251def3148818a866)
Signed-off-by: Andrej Valek <andrej.valek@siemens.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
-rw-r--r-- | meta/recipes-extended/shadow/files/CVE-2017-2616.patch | 64 | ||||
-rw-r--r-- | meta/recipes-extended/shadow/shadow.inc | 1 |
2 files changed, 65 insertions, 0 deletions
diff --git a/meta/recipes-extended/shadow/files/CVE-2017-2616.patch b/meta/recipes-extended/shadow/files/CVE-2017-2616.patch new file mode 100644 index 0000000000..ee728f0952 --- /dev/null +++ b/meta/recipes-extended/shadow/files/CVE-2017-2616.patch @@ -0,0 +1,64 @@ +shadow-4.2.1: Fix CVE-2017-2616 + +[No upstream tracking] -- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=855943 + +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 $(whoami)". Second, SIGKILL +can only be sent to processes which were executed after the su process. +It is not possible to send SIGKILL to processes which were already +running. I consider this as a security vulnerability, because I was +able to write a proof of concept which unlocked a screen saver of +another user this way. + +Upstream-Status: Backport [https://github.com/shadow-maint/shadow/commit/08fd4b69e84364677a10e519ccb25b71710ee686] +CVE: CVE-2017-2616 +bug: 855943 +Signed-off-by: Andrej Valek <andrej.valek@siemens.com> + +diff --git a/src/su.c b/src/su.c +index 3704217..1efcd61 100644 +--- a/src/su.c ++++ b/src/su.c +@@ -363,20 +363,35 @@ static void prepare_pam_close_session (void) + /* wake child when resumed */ + kill (pid, SIGCONT); + stop = false; ++ } else { ++ pid_child = 0; + } + } while (!stop); + } + +- if (0 != caught) { ++ if (0 != caught && 0 != pid_child) { + (void) fputs ("\n", stderr); + (void) fputs (_("Session terminated, terminating shell..."), + stderr); + (void) kill (-pid_child, caught); + + (void) signal (SIGALRM, kill_child); ++ (void) signal (SIGCHLD, catch_signals); + (void) alarm (2); + +- (void) wait (&status); ++ sigemptyset (&ourset); ++ if ((sigaddset (&ourset, SIGALRM) != 0) ++ || (sigprocmask (SIG_BLOCK, &ourset, NULL) != 0)) { ++ fprintf (stderr, _("%s: signal masking malfunction\n"), Prog); ++ kill_child (0); ++ } else { ++ while (0 == waitpid (pid_child, &status, WNOHANG)) { ++ sigsuspend (&ourset); ++ } ++ pid_child = 0; ++ (void) sigprocmask (SIG_UNBLOCK, &ourset, NULL); ++ } ++ + (void) fputs (_(" ...terminated.\n"), stderr); + } + diff --git a/meta/recipes-extended/shadow/shadow.inc b/meta/recipes-extended/shadow/shadow.inc index ccae09183c..5a493856a3 100644 --- a/meta/recipes-extended/shadow/shadow.inc +++ b/meta/recipes-extended/shadow/shadow.inc @@ -19,6 +19,7 @@ SRC_URI = "https://downloads.yoctoproject.org/mirror/sources/${BP}.tar.xz \ file://check_size_of_uid_t_and_gid_t_using_AC_CHECK_SIZEOF.patch \ file://0001-useradd-copy-extended-attributes-of-home.patch \ file://0001-shadow-CVE-2017-12424 \ + file://CVE-2017-2616.patch \ ${@bb.utils.contains('PACKAGECONFIG', 'pam', '${PAM_SRC_URI}', '', d)} \ " |