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CVE-2015-7613 Unauthorized access to IPC via SysV shm (rhbz 1268270 1268273)

This commit is contained in:
Josh Boyer 2015-10-02 08:11:46 -04:00
parent a95bfb8427
commit 5e3798ffdb
2 changed files with 126 additions and 0 deletions
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117
Initialize-msg-shm-IPC-objects-before-doing-ipc_addi.patch Normal file
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@ -0,0 +1,117 @@
From b9a532277938798b53178d5a66af6e2915cb27cf Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Wed, 30 Sep 2015 12:48:40 -0400
Subject: [PATCH] Initialize msg/shm IPC objects before doing ipc_addid()
As reported by Dmitry Vyukov, we really shouldn't do ipc_addid() before
having initialized the IPC object state. Yes, we initialize the IPC
object in a locked state, but with all the lockless RCU lookup work,
that IPC object lock no longer means that the state cannot be seen.
We already did this for the IPC semaphore code (see commit e8577d1f0329:
"ipc/sem.c: fully initialize sem_array before making it visible") but we
clearly forgot about msg and shm.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
ipc/msg.c | 14 +++++++-------
ipc/shm.c | 13 +++++++------
ipc/util.c | 8 ++++----
3 files changed, 18 insertions(+), 17 deletions(-)
diff --git a/ipc/msg.c b/ipc/msg.c
index 66c4f567eb73..1471db9a7e61 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -137,13 +137,6 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params)
return retval;
}
- /* ipc_addid() locks msq upon success. */
- id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
- if (id < 0) {
- ipc_rcu_putref(msq, msg_rcu_free);
- return id;
- }
-
msq->q_stime = msq->q_rtime = 0;
msq->q_ctime = get_seconds();
msq->q_cbytes = msq->q_qnum = 0;
@@ -153,6 +146,13 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params)
INIT_LIST_HEAD(&msq->q_receivers);
INIT_LIST_HEAD(&msq->q_senders);
+ /* ipc_addid() locks msq upon success. */
+ id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
+ if (id < 0) {
+ ipc_rcu_putref(msq, msg_rcu_free);
+ return id;
+ }
+
ipc_unlock_object(&msq->q_perm);
rcu_read_unlock();
diff --git a/ipc/shm.c b/ipc/shm.c
index 222131e8e38f..41787276e141 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -551,12 +551,6 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
if (IS_ERR(file))
goto no_file;
- id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
- if (id < 0) {
- error = id;
- goto no_id;
- }
-
shp->shm_cprid = task_tgid_vnr(current);
shp->shm_lprid = 0;
shp->shm_atim = shp->shm_dtim = 0;
@@ -565,6 +559,13 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
shp->shm_nattch = 0;
shp->shm_file = file;
shp->shm_creator = current;
+
+ id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
+ if (id < 0) {
+ error = id;
+ goto no_id;
+ }
+
list_add(&shp->shm_clist, &current->sysvshm.shm_clist);
/*
diff --git a/ipc/util.c b/ipc/util.c
index be4230020a1f..0f401d94b7c6 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -237,6 +237,10 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size)
rcu_read_lock();
spin_lock(&new->lock);
+ current_euid_egid(&euid, &egid);
+ new->cuid = new->uid = euid;
+ new->gid = new->cgid = egid;
+
id = idr_alloc(&ids->ipcs_idr, new,
(next_id < 0) ? 0 : ipcid_to_idx(next_id), 0,
GFP_NOWAIT);
@@ -249,10 +253,6 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size)
ids->in_use++;
- current_euid_egid(&euid, &egid);
- new->cuid = new->uid = euid;
- new->gid = new->cgid = egid;
-
if (next_id < 0) {
new->seq = ids->seq++;
if (ids->seq > IPCID_SEQ_MAX)
--
2.4.3

9
kernel.spec
View File

@ -633,6 +633,9 @@ Patch527: USB-whiteheat-fix-potential-null-deref-at-probe.patch
Patch528: dcache-Handle-escaped-paths-in-prepend_path.patch
Patch529: vfs-Test-for-and-handle-paths-that-are-unreachable-f.patch
#CVE-2015-7613 rhbz 1268270 1268273
Patch532: Initialize-msg-shm-IPC-objects-before-doing-ipc_addi.patch
# END OF PATCH DEFINITIONS
%endif
@ -1385,6 +1388,9 @@ ApplyPatch regulator-axp20x-module-alias.patch
ApplyPatch dcache-Handle-escaped-paths-in-prepend_path.patch
ApplyPatch vfs-Test-for-and-handle-paths-that-are-unreachable-f.patch
#CVE-2015-7613 rhbz 1268270 1268273
ApplyPatch Initialize-msg-shm-IPC-objects-before-doing-ipc_addi.patch
# END OF PATCH APPLICATIONS
%endif
@ -2235,6 +2241,9 @@ fi
#
#
%changelog
* Fri Oct 02 2015 Josh Boyer <jwboyer@fedoraproject.org>
- CVE-2015-7613 Unauthorized access to IPC via SysV shm (rhbz 1268270 1268273)
* Thu Oct 01 2015 Josh Boyer <jwboyer@fedoraproject.org>
- CVE-2015-2925 Don't allow bind mount escape (rhbz 1209367 1209373)