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- From: Matthias Schiffer <mschiffer@universe-factory.net>
- Date: Sat, 6 Feb 2016 07:35:33 +0100
- Subject: kernel: fix keyring reference leak (CVE-2016-0728)
- Signed-off-by: Felix Fietkau <nbd@openwrt.org>
- diff --git a/target/linux/generic/patches-3.18/010-KEYS-Fix-keyring-ref-leak-in-join_session_keyring.patch b/target/linux/generic/patches-3.18/010-KEYS-Fix-keyring-ref-leak-in-join_session_keyring.patch
- new file mode 100644
- index 0000000..9c6a969
- --- /dev/null
- +++ b/target/linux/generic/patches-3.18/010-KEYS-Fix-keyring-ref-leak-in-join_session_keyring.patch
- @@ -0,0 +1,75 @@
- +From 7ca88764d45c209791e8813131c1457c2e9e51e7 Mon Sep 17 00:00:00 2001
- +From: Yevgeny Pats <yevgeny@perception-point.io>
- +Date: Mon, 11 Jan 2016 12:05:28 +0000
- +Subject: KEYS: Fix keyring ref leak in join_session_keyring()
- +
- +If a thread is asked to join as a session keyring the keyring that's already
- +set as its session, we leak a keyring reference.
- +
- +This can be tested with the following program:
- +
- + #include <stddef.h>
- + #include <stdio.h>
- + #include <sys/types.h>
- + #include <keyutils.h>
- +
- + int main(int argc, const char *argv[])
- + {
- + int i = 0;
- + key_serial_t serial;
- +
- + serial = keyctl(KEYCTL_JOIN_SESSION_KEYRING,
- + "leaked-keyring");
- + if (serial < 0) {
- + perror("keyctl");
- + return -1;
- + }
- +
- + if (keyctl(KEYCTL_SETPERM, serial,
- + KEY_POS_ALL | KEY_USR_ALL) < 0) {
- + perror("keyctl");
- + return -1;
- + }
- +
- + for (i = 0; i < 100; i++) {
- + serial = keyctl(KEYCTL_JOIN_SESSION_KEYRING,
- + "leaked-keyring");
- + if (serial < 0) {
- + perror("keyctl");
- + return -1;
- + }
- + }
- +
- + return 0;
- + }
- +
- +If, after the program has run, there something like the following line in
- +/proc/keys:
- +
- +3f3d898f I--Q--- 100 perm 3f3f0000 0 0 keyring leaked-keyring: empty
- +
- +with a usage count of 100 * the number of times the program has been run,
- +then the kernel is malfunctioning. If leaked-keyring has zero usages or
- +has been garbage collected, then the problem is fixed.
- +
- +Reported-by: Yevgeny Pats <yevgeny@perception-point.io>
- +Signed-off-by: David Howells <dhowells@redhat.com>
- +---
- + security/keys/process_keys.c | 1 +
- + 1 file changed, 1 insertion(+)
- +
- +diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
- +index a3f85d2..e6d50172 100644
- +--- a/security/keys/process_keys.c
- ++++ b/security/keys/process_keys.c
- +@@ -794,6 +794,7 @@ long join_session_keyring(const char *name)
- + ret = PTR_ERR(keyring);
- + goto error2;
- + } else if (keyring == new->session_keyring) {
- ++ key_put(keyring);
- + ret = 0;
- + goto error2;
- + }
- +--
- +2.7.0.rc3
- +
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