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