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[Linux-stable-mirror] Patch "x86/pti: Make unpoison of pgd for trusted boot work for real" has been added to the 4.4-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/pti: Make unpoison of pgd for trusted boot work for real to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-pti-make-unpoison-of-pgd-for-trusted-boot-work-for-real.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 445b69e3b75e42362a5bdc13c8b8f61599e2228a Mon Sep 17 00:00:00 2001 From: Dave Hansen <dave.hansen(a)linux.intel.com> Date: Wed, 10 Jan 2018 14:49:39 -0800 Subject: x86/pti: Make unpoison of pgd for trusted boot work for real From: Dave Hansen <dave.hansen(a)linux.intel.com> commit 445b69e3b75e42362a5bdc13c8b8f61599e2228a upstream. The inital fix for trusted boot and PTI potentially misses the pgd clearing if pud_alloc() sets a PGD. It probably works in *practice* because for two adjacent calls to map_tboot_page() that share a PGD entry, the first will clear NX, *then* allocate and set the PGD (without NX clear). The second call will *not* allocate but will clear the NX bit. Defer the NX clearing to a point after it is known that all top-level allocations have occurred. Add a comment to clarify why. [ tglx: Massaged changelog ] [hughd notes: I have not tested tboot, but this looks to me as necessary and as safe in old-Kaiser backports as it is upstream; I'm not submitting the commit-to-be-fixed 262b6b30087, since it was undone by 445b69e3b75e, and makes conflict trouble because of 5-level's p4d versus 4-level's pgd.] Fixes: 262b6b30087 ("x86/tboot: Unbreak tboot with PTI enabled") Signed-off-by: Dave Hansen <dave.hansen(a)linux.intel.com> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Reviewed-by: Andrea Arcangeli <aarcange(a)redhat.com> Cc: Jon Masters <jcm(a)redhat.com> Cc: "Tim Chen" <tim.c.chen(a)linux.intel.com> Cc: gnomes(a)lxorguk.ukuu.org.uk Cc: peterz(a)infradead.org Cc: ning.sun(a)intel.com Cc: tboot-devel(a)lists.sourceforge.net Cc: andi(a)firstfloor.org Cc: luto(a)kernel.org Cc: law(a)redhat.com Cc: pbonzini(a)redhat.com Cc: torvalds(a)linux-foundation.org Cc: gregkh(a)linux-foundation.org Cc: dwmw(a)amazon.co.uk Cc: nickc(a)redhat.com Cc: stable(a)vger.kernel.org Link: https://lkml.kernel.org/r/20180110224939.2695CD47@viggo.jf.intel.com Signed-off-by: Hugh Dickins <hughd(a)google.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/tboot.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/arch/x86/kernel/tboot.c +++ b/arch/x86/kernel/tboot.c @@ -140,6 +140,16 @@ static int map_tboot_page(unsigned long return -1; set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot)); pte_unmap(pte); + + /* + * PTI poisons low addresses in the kernel page tables in the + * name of making them unusable for userspace. To execute + * code at such a low address, the poison must be cleared. + * + * Note: 'pgd' actually gets set in pud_alloc(). + */ + pgd->pgd &= ~_PAGE_NX; + return 0; } Patches currently in stable-queue which might be from dave.hansen(a)linux.intel.com are queue-4.4/x86-pti-make-unpoison-of-pgd-for-trusted-boot-work-for-real.patch

7 years, 5 months

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[Linux-stable-mirror] Patch "ALSA: seq: Make ioctls race-free" has been added to the 4.4-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled ALSA: seq: Make ioctls race-free to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: alsa-seq-make-ioctls-race-free.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From b3defb791b26ea0683a93a4f49c77ec45ec96f10 Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai(a)suse.de> Date: Tue, 9 Jan 2018 23:11:03 +0100 Subject: ALSA: seq: Make ioctls race-free From: Takashi Iwai <tiwai(a)suse.de> commit b3defb791b26ea0683a93a4f49c77ec45ec96f10 upstream. The ALSA sequencer ioctls have no protection against racy calls while the concurrent operations may lead to interfere with each other. As reported recently, for example, the concurrent calls of setting client pool with a combination of write calls may lead to either the unkillable dead-lock or UAF. As a slightly big hammer solution, this patch introduces the mutex to make each ioctl exclusive. Although this may reduce performance via parallel ioctl calls, usually it's not demanded for sequencer usages, hence it should be negligible. Reported-by: Luo Quan <a4651386(a)163.com> Reviewed-by: Kees Cook <keescook(a)chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Takashi Iwai <tiwai(a)suse.de> [bwh: Backported to 4.4: ioctl dispatch is done from snd_seq_do_ioctl(); take the mutex and add ret variable there.] Signed-off-by: Ben Hutchings <ben.hutchings(a)codethink.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- sound/core/seq/seq_clientmgr.c | 10 ++++++++-- sound/core/seq/seq_clientmgr.h | 1 + 2 files changed, 9 insertions(+), 2 deletions(-) --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -236,6 +236,7 @@ static struct snd_seq_client *seq_create rwlock_init(&client->ports_lock); mutex_init(&client->ports_mutex); INIT_LIST_HEAD(&client->ports_list_head); + mutex_init(&client->ioctl_mutex); /* find free slot in the client table */ spin_lock_irqsave(&clients_lock, flags); @@ -2195,6 +2196,7 @@ static int snd_seq_do_ioctl(struct snd_s void __user *arg) { struct seq_ioctl_table *p; + int ret; switch (cmd) { case SNDRV_SEQ_IOCTL_PVERSION: @@ -2208,8 +2210,12 @@ static int snd_seq_do_ioctl(struct snd_s if (! arg) return -EFAULT; for (p = ioctl_tables; p->cmd; p++) { - if (p->cmd == cmd) - return p->func(client, arg); + if (p->cmd == cmd) { + mutex_lock(&client->ioctl_mutex); + ret = p->func(client, arg); + mutex_unlock(&client->ioctl_mutex); + return ret; + } } pr_debug("ALSA: seq unknown ioctl() 0x%x (type='%c', number=0x%02x)\n", cmd, _IOC_TYPE(cmd), _IOC_NR(cmd)); --- a/sound/core/seq/seq_clientmgr.h +++ b/sound/core/seq/seq_clientmgr.h @@ -59,6 +59,7 @@ struct snd_seq_client { struct list_head ports_list_head; rwlock_t ports_lock; struct mutex ports_mutex; + struct mutex ioctl_mutex; int convert32; /* convert 32->64bit */ /* output pool */ Patches currently in stable-queue which might be from tiwai(a)suse.de are queue-4.4/alsa-seq-make-ioctls-race-free.patch

7 years, 5 months

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[Linux-stable-mirror] Patch "KVM: x86: Fix CPUID function for word 6 (80000001_ECX)" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled KVM: x86: Fix CPUID function for word 6 (80000001_ECX) to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: kvm-x86-fix-cpuid-function-for-word-6-80000001_ecx.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 50a671d4d15b859f447fa527191073019b6ce9cb Mon Sep 17 00:00:00 2001 From: Janakarajan Natarajan <Janakarajan.Natarajan(a)amd.com> Date: Mon, 6 Nov 2017 11:44:23 -0600 Subject: KVM: x86: Fix CPUID function for word 6 (80000001_ECX) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Janakarajan Natarajan <Janakarajan.Natarajan(a)amd.com> commit 50a671d4d15b859f447fa527191073019b6ce9cb upstream. The function for CPUID 80000001 ECX is set to 0xc0000001. Set it to 0x80000001. Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan(a)amd.com> Reviewed-by: Jim Mattson <jmattson(a)google.com> Reviewed-by: Krish Sadhukhan <krish.sadhukhan(a)oracle.com> Reviewed-by: Borislav Petkov <bp(a)suse.de> Fixes: d6321d493319 ("KVM: x86: generalize guest_cpuid_has_ helpers") Signed-off-by: Radim Krčmář <rkrcmar(a)redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kvm/cpuid.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/kvm/cpuid.h +++ b/arch/x86/kvm/cpuid.h @@ -44,7 +44,7 @@ static const struct cpuid_reg reverse_cp [CPUID_8086_0001_EDX] = {0x80860001, 0, CPUID_EDX}, [CPUID_1_ECX] = { 1, 0, CPUID_ECX}, [CPUID_C000_0001_EDX] = {0xc0000001, 0, CPUID_EDX}, - [CPUID_8000_0001_ECX] = {0xc0000001, 0, CPUID_ECX}, + [CPUID_8000_0001_ECX] = {0x80000001, 0, CPUID_ECX}, [CPUID_7_0_EBX] = { 7, 0, CPUID_EBX}, [CPUID_D_1_EAX] = { 0xd, 1, CPUID_EAX}, [CPUID_F_0_EDX] = { 0xf, 0, CPUID_EDX}, Patches currently in stable-queue which might be from Janakarajan.Natarajan(a)amd.com are queue-4.14/kvm-x86-fix-cpuid-function-for-word-6-80000001_ecx.patch

7 years, 5 months

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[Linux-stable-mirror] Patch "ALSA: seq: Make ioctls race-free" has been added to the 3.18-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled ALSA: seq: Make ioctls race-free to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: alsa-seq-make-ioctls-race-free.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From b3defb791b26ea0683a93a4f49c77ec45ec96f10 Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai(a)suse.de> Date: Tue, 9 Jan 2018 23:11:03 +0100 Subject: ALSA: seq: Make ioctls race-free From: Takashi Iwai <tiwai(a)suse.de> commit b3defb791b26ea0683a93a4f49c77ec45ec96f10 upstream. The ALSA sequencer ioctls have no protection against racy calls while the concurrent operations may lead to interfere with each other. As reported recently, for example, the concurrent calls of setting client pool with a combination of write calls may lead to either the unkillable dead-lock or UAF. As a slightly big hammer solution, this patch introduces the mutex to make each ioctl exclusive. Although this may reduce performance via parallel ioctl calls, usually it's not demanded for sequencer usages, hence it should be negligible. Reported-by: Luo Quan <a4651386(a)163.com> Reviewed-by: Kees Cook <keescook(a)chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Takashi Iwai <tiwai(a)suse.de> [bwh: Backported to 4.4: ioctl dispatch is done from snd_seq_do_ioctl(); take the mutex and add ret variable there.] Signed-off-by: Ben Hutchings <ben.hutchings(a)codethink.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- sound/core/seq/seq_clientmgr.c | 10 ++++++++-- sound/core/seq/seq_clientmgr.h | 1 + 2 files changed, 9 insertions(+), 2 deletions(-) --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -236,6 +236,7 @@ static struct snd_seq_client *seq_create rwlock_init(&client->ports_lock); mutex_init(&client->ports_mutex); INIT_LIST_HEAD(&client->ports_list_head); + mutex_init(&client->ioctl_mutex); /* find free slot in the client table */ spin_lock_irqsave(&clients_lock, flags); @@ -2200,6 +2201,7 @@ static int snd_seq_do_ioctl(struct snd_s void __user *arg) { struct seq_ioctl_table *p; + int ret; switch (cmd) { case SNDRV_SEQ_IOCTL_PVERSION: @@ -2213,8 +2215,12 @@ static int snd_seq_do_ioctl(struct snd_s if (! arg) return -EFAULT; for (p = ioctl_tables; p->cmd; p++) { - if (p->cmd == cmd) - return p->func(client, arg); + if (p->cmd == cmd) { + mutex_lock(&client->ioctl_mutex); + ret = p->func(client, arg); + mutex_unlock(&client->ioctl_mutex); + return ret; + } } pr_debug("ALSA: seq unknown ioctl() 0x%x (type='%c', number=0x%02x)\n", cmd, _IOC_TYPE(cmd), _IOC_NR(cmd)); --- a/sound/core/seq/seq_clientmgr.h +++ b/sound/core/seq/seq_clientmgr.h @@ -59,6 +59,7 @@ struct snd_seq_client { struct list_head ports_list_head; rwlock_t ports_lock; struct mutex ports_mutex; + struct mutex ioctl_mutex; int convert32; /* convert 32->64bit */ /* output pool */ Patches currently in stable-queue which might be from tiwai(a)suse.de are queue-3.18/alsa-seq-make-ioctls-race-free.patch

7 years, 5 months

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[Linux-stable-mirror] [PATCH] general protection fault in sock_has_perm

by Mark Salyzyn

general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 14233 Comm: syz-executor2 Not tainted 4.4.112-g5f6325b #28 task: ffff8801d1095f00 task.stack: ffff8800b5950000 RIP: 0010:[<ffffffff81b69b7e>] [<ffffffff81b69b7e>] sock_has_perm+0x1fe/0x3e0 security/selinux/hooks.c:4069 RSP: 0018:ffff8800b5957ce0 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 1ffff10016b2af9f RCX: ffffffff81b69b51 RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000010 RBP: ffff8800b5957de0 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 1ffff10016b2af68 R12: ffff8800b5957db8 R13: 0000000000000000 R14: ffff8800b7259f40 R15: 00000000000000d7 FS: 00007f72f5ae2700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000a2fa38 CR3: 00000001d7980000 CR4: 0000000000160670 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff81b69a1f ffff8800b5957d58 00008000b5957d30 0000000041b58ab3 ffffffff83fc82f2 ffffffff81b69980 0000000000000246 ffff8801d1096770 ffff8801d3165668 ffffffff8157844b ffff8801d1095f00 ffff880000000001 Call Trace: [<ffffffff81b6a19d>] selinux_socket_setsockopt+0x4d/0x80 security/selinux/hooks.c:4338 [<ffffffff81b4873d>] security_socket_setsockopt+0x7d/0xb0 security/security.c:1257 [<ffffffff82df1ac8>] SYSC_setsockopt net/socket.c:1757 [inline] [<ffffffff82df1ac8>] SyS_setsockopt+0xe8/0x250 net/socket.c:1746 [<ffffffff83776499>] entry_SYSCALL_64_fastpath+0x16/0x92 Code: c2 42 9b b6 81 be 01 00 00 00 48 c7 c7 a0 cb 2b 84 e8 f7 2f 6d ff 49 8d 7d 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 83 01 00 00 41 8b 75 10 31 RIP [<ffffffff81b69b7e>] sock_has_perm+0x1fe/0x3e0 security/selinux/hooks.c:4069 RSP <ffff8800b5957ce0> ---[ end trace 7b5aaf788fef6174 ]--- In the absence of commit a4298e4522d6 ("net: add SOCK_RCU_FREE socket flag") and all the associated infrastructure changes to take advantage of a RCU grace period before freeing, there is a heightened possibility that a security check is performed while an ill-timed setsockopt call races in from user space. It then is prudent to null check sk_security, and if the case, reject the permissions. This adjustment is orthogonal to infrastructure improvements that may nullify the needed check, but should be added as good code hygiene. Signed-off-by: Mark Salyzyn <salyzyn(a)android.com> Cc: Paul Moore <paul(a)paul-moore.com> Cc: Stephen Smalley <sds(a)tycho.nsa.gov> Cc: Eric Paris <eparis(a)parisplace.org> Cc: James Morris <james.l.morris(a)oracle.com> Cc: "Serge E. Hallyn" <serge(a)hallyn.com> Cc: selinux(a)tycho.nsa.gov Cc: linux-security-module(a)vger.kernel.org Cc: linux-kernel(a)vger.kernel.org Cc: stable(a)vger.kernel.org --- This patch should be applied to all stable trees (author wants minimum of 3.18, 4.4, 4.9 and 4.14) security/selinux/hooks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 8644d864e3c1..95d7c8143373 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -4342,7 +4342,7 @@ static int sock_has_perm(struct sock *sk, u32 perms) struct common_audit_data ad; struct lsm_network_audit net = {0,}; - if (sksec->sid == SECINITSID_KERNEL) + if (!sksec || sksec->sid == SECINITSID_KERNEL) return 0; ad.type = LSM_AUDIT_DATA_NET; -- 2.16.0.rc1.238.g530d649a79-goog

7 years, 5 months

5
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[Linux-stable-mirror] [PATCH 4.4] ALSA: seq: Make ioctls race-free

by Ben Hutchings

commit b3defb791b26ea0683a93a4f49c77ec45ec96f10 upstream. The ALSA sequencer ioctls have no protection against racy calls while the concurrent operations may lead to interfere with each other. As reported recently, for example, the concurrent calls of setting client pool with a combination of write calls may lead to either the unkillable dead-lock or UAF. As a slightly big hammer solution, this patch introduces the mutex to make each ioctl exclusive. Although this may reduce performance via parallel ioctl calls, usually it's not demanded for sequencer usages, hence it should be negligible. Reported-by: Luo Quan <a4651386(a)163.com> Reviewed-by: Kees Cook <keescook(a)chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Takashi Iwai <tiwai(a)suse.de> [bwh: Backported to 4.4: ioctl dispatch is done from snd_seq_do_ioctl(); take the mutex and add ret variable there.] Signed-off-by: Ben Hutchings <ben.hutchings(a)codethink.co.uk> --- sound/core/seq/seq_clientmgr.c | 10 ++++++++-- sound/core/seq/seq_clientmgr.h | 1 + 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/sound/core/seq/seq_clientmgr.c b/sound/core/seq/seq_clientmgr.c index b36de76f24e2..7bb9fe7a2c8e 100644 --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -236,6 +236,7 @@ static struct snd_seq_client *seq_create_client1(int client_index, int poolsize) rwlock_init(&client->ports_lock); mutex_init(&client->ports_mutex); INIT_LIST_HEAD(&client->ports_list_head); + mutex_init(&client->ioctl_mutex); /* find free slot in the client table */ spin_lock_irqsave(&clients_lock, flags); @@ -2195,6 +2196,7 @@ static int snd_seq_do_ioctl(struct snd_seq_client *client, unsigned int cmd, void __user *arg) { struct seq_ioctl_table *p; + int ret; switch (cmd) { case SNDRV_SEQ_IOCTL_PVERSION: @@ -2208,8 +2210,12 @@ static int snd_seq_do_ioctl(struct snd_seq_client *client, unsigned int cmd, if (! arg) return -EFAULT; for (p = ioctl_tables; p->cmd; p++) { - if (p->cmd == cmd) - return p->func(client, arg); + if (p->cmd == cmd) { + mutex_lock(&client->ioctl_mutex); + ret = p->func(client, arg); + mutex_unlock(&client->ioctl_mutex); + return ret; + } } pr_debug("ALSA: seq unknown ioctl() 0x%x (type='%c', number=0x%02x)\n", cmd, _IOC_TYPE(cmd), _IOC_NR(cmd)); diff --git a/sound/core/seq/seq_clientmgr.h b/sound/core/seq/seq_clientmgr.h index 20f0a725ec7d..91f8f165bfdc 100644 --- a/sound/core/seq/seq_clientmgr.h +++ b/sound/core/seq/seq_clientmgr.h @@ -59,6 +59,7 @@ struct snd_seq_client { struct list_head ports_list_head; rwlock_t ports_lock; struct mutex ports_mutex; + struct mutex ioctl_mutex; int convert32; /* convert 32->64bit */ /* output pool */ -- 2.15.0.rc0

7 years, 5 months

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[Linux-stable-mirror] [PATCH v2 4.4 1/3] bpf: fix branch pruning logic

by Ben Hutchings

From: Alexei Starovoitov <ast(a)fb.com> commit c131187db2d3fa2f8bf32fdf4e9a4ef805168467 upstream. when the verifier detects that register contains a runtime constant and it's compared with another constant it will prune exploration of the branch that is guaranteed not to be taken at runtime. This is all correct, but malicious program may be constructed in such a way that it always has a constant comparison and the other branch is never taken under any conditions. In this case such path through the program will not be explored by the verifier. It won't be taken at run-time either, but since all instructions are JITed the malicious program may cause JITs to complain about using reserved fields, etc. To fix the issue we have to track the instructions explored by the verifier and sanitize instructions that are dead at run time with NOPs. We cannot reject such dead code, since llvm generates it for valid C code, since it doesn't do as much data flow analysis as the verifier does. Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)") Signed-off-by: Alexei Starovoitov <ast(a)kernel.org> Acked-by: Daniel Borkmann <daniel(a)iogearbox.net> Signed-off-by: Daniel Borkmann <daniel(a)iogearbox.net> [bwh: Backported to 4.4: - s/bpf_verifier_env/verifier_env/ - Adjust context] Signed-off-by: Ben Hutchings <ben.hutchings(a)codethink.co.uk> --- v2: Restore Alexei as author kernel/bpf/verifier.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 014c2d759916..a62679711de0 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -191,6 +191,7 @@ struct bpf_insn_aux_data { enum bpf_reg_type ptr_type; /* pointer type for load/store insns */ struct bpf_map *map_ptr; /* pointer for call insn into lookup_elem */ }; + bool seen; /* this insn was processed by the verifier */ }; #define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */ @@ -1793,6 +1794,7 @@ static int do_check(struct verifier_env *env) print_bpf_insn(env, insn); } + env->insn_aux_data[insn_idx].seen = true; if (class == BPF_ALU || class == BPF_ALU64) { err = check_alu_op(env, insn); if (err) @@ -1988,6 +1990,7 @@ process_bpf_exit: return err; insn_idx++; + env->insn_aux_data[insn_idx].seen = true; } else { verbose("invalid BPF_LD mode\n"); return -EINVAL; @@ -2125,6 +2128,7 @@ static int adjust_insn_aux_data(struct verifier_env *env, u32 prog_len, u32 off, u32 cnt) { struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data; + int i; if (cnt == 1) return 0; @@ -2134,6 +2138,8 @@ static int adjust_insn_aux_data(struct verifier_env *env, u32 prog_len, memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off); memcpy(new_data + off + cnt - 1, old_data + off, sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1)); + for (i = off; i < off + cnt - 1; i++) + new_data[i].seen = true; env->insn_aux_data = new_data; vfree(old_data); return 0; @@ -2152,6 +2158,25 @@ static struct bpf_prog *bpf_patch_insn_data(struct verifier_env *env, u32 off, return new_prog; } +/* The verifier does more data flow analysis than llvm and will not explore + * branches that are dead at run time. Malicious programs can have dead code + * too. Therefore replace all dead at-run-time code with nops. + */ +static void sanitize_dead_code(struct verifier_env *env) +{ + struct bpf_insn_aux_data *aux_data = env->insn_aux_data; + struct bpf_insn nop = BPF_MOV64_REG(BPF_REG_0, BPF_REG_0); + struct bpf_insn *insn = env->prog->insnsi; + const int insn_cnt = env->prog->len; + int i; + + for (i = 0; i < insn_cnt; i++) { + if (aux_data[i].seen) + continue; + memcpy(insn + i, &nop, sizeof(nop)); + } +} + /* convert load instructions that access fields of 'struct __sk_buff' * into sequence of instructions that access fields of 'struct sk_buff' */ @@ -2370,6 +2395,9 @@ skip_full_check: while (pop_stack(env, NULL) >= 0); free_states(env); + if (ret == 0) + sanitize_dead_code(env); + if (ret == 0) /* program is valid, convert *(u32*)(ctx + off) accesses */ ret = convert_ctx_accesses(env); -- 2.15.0.rc0

7 years, 5 months

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[Linux-stable-mirror] [PATCH 4.4 1/3] bpf: fix branch pruning logic

by Ben Hutchings

commit c131187db2d3fa2f8bf32fdf4e9a4ef805168467 upstream. when the verifier detects that register contains a runtime constant and it's compared with another constant it will prune exploration of the branch that is guaranteed not to be taken at runtime. This is all correct, but malicious program may be constructed in such a way that it always has a constant comparison and the other branch is never taken under any conditions. In this case such path through the program will not be explored by the verifier. It won't be taken at run-time either, but since all instructions are JITed the malicious program may cause JITs to complain about using reserved fields, etc. To fix the issue we have to track the instructions explored by the verifier and sanitize instructions that are dead at run time with NOPs. We cannot reject such dead code, since llvm generates it for valid C code, since it doesn't do as much data flow analysis as the verifier does. Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)") Signed-off-by: Alexei Starovoitov <ast(a)kernel.org> Acked-by: Daniel Borkmann <daniel(a)iogearbox.net> Signed-off-by: Daniel Borkmann <daniel(a)iogearbox.net> [bwh: Backported to 4.4: - s/bpf_verifier_env/verifier_env/ - Adjust context] Signed-off-by: Ben Hutchings <ben.hutchings(a)codethink.co.uk> --- kernel/bpf/verifier.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 014c2d759916..a62679711de0 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -191,6 +191,7 @@ struct bpf_insn_aux_data { enum bpf_reg_type ptr_type; /* pointer type for load/store insns */ struct bpf_map *map_ptr; /* pointer for call insn into lookup_elem */ }; + bool seen; /* this insn was processed by the verifier */ }; #define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */ @@ -1793,6 +1794,7 @@ static int do_check(struct verifier_env *env) print_bpf_insn(env, insn); } + env->insn_aux_data[insn_idx].seen = true; if (class == BPF_ALU || class == BPF_ALU64) { err = check_alu_op(env, insn); if (err) @@ -1988,6 +1990,7 @@ process_bpf_exit: return err; insn_idx++; + env->insn_aux_data[insn_idx].seen = true; } else { verbose("invalid BPF_LD mode\n"); return -EINVAL; @@ -2125,6 +2128,7 @@ static int adjust_insn_aux_data(struct verifier_env *env, u32 prog_len, u32 off, u32 cnt) { struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data; + int i; if (cnt == 1) return 0; @@ -2134,6 +2138,8 @@ static int adjust_insn_aux_data(struct verifier_env *env, u32 prog_len, memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off); memcpy(new_data + off + cnt - 1, old_data + off, sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1)); + for (i = off; i < off + cnt - 1; i++) + new_data[i].seen = true; env->insn_aux_data = new_data; vfree(old_data); return 0; @@ -2152,6 +2158,25 @@ static struct bpf_prog *bpf_patch_insn_data(struct verifier_env *env, u32 off, return new_prog; } +/* The verifier does more data flow analysis than llvm and will not explore + * branches that are dead at run time. Malicious programs can have dead code + * too. Therefore replace all dead at-run-time code with nops. + */ +static void sanitize_dead_code(struct verifier_env *env) +{ + struct bpf_insn_aux_data *aux_data = env->insn_aux_data; + struct bpf_insn nop = BPF_MOV64_REG(BPF_REG_0, BPF_REG_0); + struct bpf_insn *insn = env->prog->insnsi; + const int insn_cnt = env->prog->len; + int i; + + for (i = 0; i < insn_cnt; i++) { + if (aux_data[i].seen) + continue; + memcpy(insn + i, &nop, sizeof(nop)); + } +} + /* convert load instructions that access fields of 'struct __sk_buff' * into sequence of instructions that access fields of 'struct sk_buff' */ @@ -2370,6 +2395,9 @@ skip_full_check: while (pop_stack(env, NULL) >= 0); free_states(env); + if (ret == 0) + sanitize_dead_code(env); + if (ret == 0) /* program is valid, convert *(u32*)(ctx + off) accesses */ ret = convert_ctx_accesses(env); -- 2.15.0.rc0

7 years, 5 months

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[Linux-stable-mirror] [PATCH 4.4] x86/pti: Make unpoison of pgd for trusted boot work for real

by Hugh Dickins

From: Dave Hansen <dave.hansen(a)linux.intel.com> commit 445b69e3b75e42362a5bdc13c8b8f61599e2228a upstream The inital fix for trusted boot and PTI potentially misses the pgd clearing if pud_alloc() sets a PGD. It probably works in *practice* because for two adjacent calls to map_tboot_page() that share a PGD entry, the first will clear NX, *then* allocate and set the PGD (without NX clear). The second call will *not* allocate but will clear the NX bit. Defer the NX clearing to a point after it is known that all top-level allocations have occurred. Add a comment to clarify why. [ tglx: Massaged changelog ] Fixes: 262b6b30087 ("x86/tboot: Unbreak tboot with PTI enabled") Signed-off-by: Dave Hansen <dave.hansen(a)linux.intel.com> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Reviewed-by: Andrea Arcangeli <aarcange(a)redhat.com> Cc: Jon Masters <jcm(a)redhat.com> Cc: Tim Chen <tim.c.chen(a)linux.intel.com> Cc: gnomes(a)lxorguk.ukuu.org.uk Cc: peterz(a)infradead.org Cc: ning.sun(a)intel.com Cc: tboot-devel(a)lists.sourceforge.net Cc: andi(a)firstfloor.org Cc: luto(a)kernel.org Cc: law(a)redhat.com Cc: pbonzini(a)redhat.com Cc: torvalds(a)linux-foundation.org Cc: gregkh(a)linux-foundation.org Cc: dwmw(a)amazon.co.uk Cc: nickc(a)redhat.com Cc: stable(a)vger.kernel.org Link: https://lkml.kernel.org/r/20180110224939.2695CD47@viggo.jf.intel.com Cc: Jiri Kosina <jkosina(a)suse.cz> Signed-off-by: Hugh Dickins <hughd(a)google.com> hughd notes: I have not tested tboot, but this looks to me as necessary and as safe in old-Kaiser backports as it is upstream; I'm not submitting the commit-to-be-fixed 262b6b30087, since it was undone by 445b69e3b75e, and makes conflict trouble because of 5-level's p4d versus 4-level's pgd. --- arch/x86/kernel/tboot.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c index 91a4496db434..c77ab1f51fbe 100644 --- a/arch/x86/kernel/tboot.c +++ b/arch/x86/kernel/tboot.c @@ -140,6 +140,16 @@ static int map_tboot_page(unsigned long vaddr, unsigned long pfn, return -1; set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot)); pte_unmap(pte); + + /* + * PTI poisons low addresses in the kernel page tables in the + * name of making them unusable for userspace. To execute + * code at such a low address, the poison must be cleared. + * + * Note: 'pgd' actually gets set in pud_alloc(). + */ + pgd->pgd &= ~_PAGE_NX; + return 0; } -- 2.16.0.rc1.238.g530d649a79-goog

7 years, 5 months

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[Linux-stable-mirror] [PATCH stable 4.4 0/9] BPF stable patches

by Daniel Borkmann

All for 4.4 backported and (limited) testing. Thanks! Alexei Starovoitov (3): bpf: fix bpf_tail_call() x64 JIT bpf: introduce BPF_JIT_ALWAYS_ON config bpf: fix 32-bit divide by zero Daniel Borkmann (4): bpf: fix branch pruning logic bpf: arsh is not supported in 32 bit alu thus reject it bpf: avoid false sharing of map refcount with max_entries bpf: reject stores into ctx via st and xadd Eric Dumazet (2): x86: bpf_jit: small optimization in emit_bpf_tail_call() bpf: fix divides by zero arch/arm64/Kconfig | 1 + arch/s390/Kconfig | 1 + arch/x86/Kconfig | 1 + arch/x86/net/bpf_jit_comp.c | 13 ++++----- include/linux/bpf.h | 16 ++++++++--- init/Kconfig | 7 +++++ kernel/bpf/core.c | 30 ++++++++++++++++--- kernel/bpf/verifier.c | 70 +++++++++++++++++++++++++++++++++++++++++++++ lib/test_bpf.c | 13 +++++---- net/Kconfig | 3 ++ net/core/filter.c | 8 +++++- net/core/sysctl_net_core.c | 6 ++++ net/socket.c | 9 ++++++ 13 files changed, 157 insertions(+), 21 deletions(-) -- 2.9.5

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