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authorAndrej Valek <andrej.valek@siemens.com>2018-07-24 13:08:29 +0200
committerRichard Purdie <richard.purdie@linuxfoundation.org>2018-07-26 13:16:41 +0100
commitb22e18b7a0e5979c7f80f8ca0ce1e21c8f04aa3c (patch)
treee62c1aa739dbf95ec63bce80b3e0eeda727e3021 /meta/recipes-extended/shadow
parent3a6ccf52271e950b54a67862307c29da07ffd7a5 (diff)
downloadpoky-b22e18b7a0e5979c7f80f8ca0ce1e21c8f04aa3c.tar.gz
shadow: fix CVE-2017-2616
(From OE-Core rev: 94a1e2794df15f0f2cb62ae030cd81e6c0798b1f) 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>
Diffstat (limited to 'meta/recipes-extended/shadow')
-rw-r--r--meta/recipes-extended/shadow/files/CVE-2017-2616.patch64
-rw-r--r--meta/recipes-extended/shadow/shadow.inc1
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 @@
1shadow-4.2.1: Fix CVE-2017-2616
2
3[No upstream tracking] -- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=855943
4
5su: properly clear child PID
6
7If su is compiled with PAM support, it is possible for any local user
8to send SIGKILL to other processes with root privileges. There are
9only two conditions. First, the user must be able to perform su with
10a successful login. This does NOT have to be the root user, even using
11su with the same id is enough, e.g. "su $(whoami)". Second, SIGKILL
12can only be sent to processes which were executed after the su process.
13It is not possible to send SIGKILL to processes which were already
14running. I consider this as a security vulnerability, because I was
15able to write a proof of concept which unlocked a screen saver of
16another user this way.
17
18Upstream-Status: Backport [https://github.com/shadow-maint/shadow/commit/08fd4b69e84364677a10e519ccb25b71710ee686]
19CVE: CVE-2017-2616
20bug: 855943
21Signed-off-by: Andrej Valek <andrej.valek@siemens.com>
22
23diff --git a/src/su.c b/src/su.c
24index 3704217..1efcd61 100644
25--- a/src/su.c
26+++ b/src/su.c
27@@ -363,20 +363,35 @@ static void prepare_pam_close_session (void)
28 /* wake child when resumed */
29 kill (pid, SIGCONT);
30 stop = false;
31+ } else {
32+ pid_child = 0;
33 }
34 } while (!stop);
35 }
36
37- if (0 != caught) {
38+ if (0 != caught && 0 != pid_child) {
39 (void) fputs ("\n", stderr);
40 (void) fputs (_("Session terminated, terminating shell..."),
41 stderr);
42 (void) kill (-pid_child, caught);
43
44 (void) signal (SIGALRM, kill_child);
45+ (void) signal (SIGCHLD, catch_signals);
46 (void) alarm (2);
47
48- (void) wait (&status);
49+ sigemptyset (&ourset);
50+ if ((sigaddset (&ourset, SIGALRM) != 0)
51+ || (sigprocmask (SIG_BLOCK, &ourset, NULL) != 0)) {
52+ fprintf (stderr, _("%s: signal masking malfunction\n"), Prog);
53+ kill_child (0);
54+ } else {
55+ while (0 == waitpid (pid_child, &status, WNOHANG)) {
56+ sigsuspend (&ourset);
57+ }
58+ pid_child = 0;
59+ (void) sigprocmask (SIG_UNBLOCK, &ourset, NULL);
60+ }
61+
62 (void) fputs (_(" ...terminated.\n"), stderr);
63 }
64
diff --git a/meta/recipes-extended/shadow/shadow.inc b/meta/recipes-extended/shadow/shadow.inc
index 9a08918818..6efe4a9119 100644
--- a/meta/recipes-extended/shadow/shadow.inc
+++ b/meta/recipes-extended/shadow/shadow.inc
@@ -18,6 +18,7 @@ SRC_URI = "https://downloads.yoctoproject.org/mirror/sources/${BP}.tar.xz \
18 file://check_size_of_uid_t_and_gid_t_using_AC_CHECK_SIZEOF.patch \ 18 file://check_size_of_uid_t_and_gid_t_using_AC_CHECK_SIZEOF.patch \
19 file://0001-useradd-copy-extended-attributes-of-home.patch \ 19 file://0001-useradd-copy-extended-attributes-of-home.patch \
20 file://0001-shadow-CVE-2017-12424 \ 20 file://0001-shadow-CVE-2017-12424 \
21 file://CVE-2017-2616.patch \
21 ${@bb.utils.contains('PACKAGECONFIG', 'pam', '${PAM_SRC_URI}', '', d)} \ 22 ${@bb.utils.contains('PACKAGECONFIG', 'pam', '${PAM_SRC_URI}', '', d)} \
22 " 23 "
23 24