2017-08-14 18:43:11

by Alexander Potapenko

[permalink] [raw]
Subject: [PATCH v2] sctp: fully initialize the IPv6 address in sctp_v6_to_addr()

KMSAN reported use of uninitialized sctp_addr->v4.sin_addr.s_addr and
sctp_addr->v6.sin6_scope_id in sctp_v6_cmp_addr() (see below).
Make sure all fields of an IPv6 address are initialized, which
guarantees that the IPv4 fields are also initialized.

==================================================================
BUG: KMSAN: use of uninitialized memory in sctp_v6_cmp_addr+0x8d4/0x9f0
net/sctp/ipv6.c:517
CPU: 2 PID: 31056 Comm: syz-executor1 Not tainted 4.11.0-rc5+ #2944
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
01/01/2011
Call Trace:
dump_stack+0x172/0x1c0 lib/dump_stack.c:42
is_logbuf_locked mm/kmsan/kmsan.c:59 [inline]
kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:938
native_save_fl arch/x86/include/asm/irqflags.h:18 [inline]
arch_local_save_flags arch/x86/include/asm/irqflags.h:72 [inline]
arch_local_irq_save arch/x86/include/asm/irqflags.h:113 [inline]
__msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:467
sctp_v6_cmp_addr+0x8d4/0x9f0 net/sctp/ipv6.c:517
sctp_v6_get_dst+0x8c7/0x1630 net/sctp/ipv6.c:290
sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
sctp_assoc_add_peer+0x66d/0x16f0 net/sctp/associola.c:651
sctp_sendmsg+0x35a5/0x4f90 net/sctp/socket.c:1871
inet_sendmsg+0x498/0x670 net/ipv4/af_inet.c:762
sock_sendmsg_nosec net/socket.c:633 [inline]
sock_sendmsg net/socket.c:643 [inline]
SYSC_sendto+0x608/0x710 net/socket.c:1696
SyS_sendto+0x8a/0xb0 net/socket.c:1664
entry_SYSCALL_64_fastpath+0x13/0x94
RIP: 0033:0x44b479
RSP: 002b:00007f6213f21c08 EFLAGS: 00000286 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 000000000044b479
RDX: 0000000000000041 RSI: 0000000020edd000 RDI: 0000000000000006
RBP: 00000000007080a8 R08: 0000000020b85fe4 R09: 000000000000001c
R10: 0000000000040005 R11: 0000000000000286 R12: 00000000ffffffff
R13: 0000000000003760 R14: 00000000006e5820 R15: 0000000000ff8000
origin description: ----dst_saddr@sctp_v6_get_dst
local variable created at:
sk_fullsock include/net/sock.h:2321 [inline]
inet6_sk include/linux/ipv6.h:309 [inline]
sctp_v6_get_dst+0x91/0x1630 net/sctp/ipv6.c:241
sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
==================================================================
BUG: KMSAN: use of uninitialized memory in sctp_v6_cmp_addr+0x8d4/0x9f0
net/sctp/ipv6.c:517
CPU: 2 PID: 31056 Comm: syz-executor1 Not tainted 4.11.0-rc5+ #2944
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
01/01/2011
Call Trace:
dump_stack+0x172/0x1c0 lib/dump_stack.c:42
is_logbuf_locked mm/kmsan/kmsan.c:59 [inline]
kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:938
native_save_fl arch/x86/include/asm/irqflags.h:18 [inline]
arch_local_save_flags arch/x86/include/asm/irqflags.h:72 [inline]
arch_local_irq_save arch/x86/include/asm/irqflags.h:113 [inline]
__msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:467
sctp_v6_cmp_addr+0x8d4/0x9f0 net/sctp/ipv6.c:517
sctp_v6_get_dst+0x8c7/0x1630 net/sctp/ipv6.c:290
sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
sctp_assoc_add_peer+0x66d/0x16f0 net/sctp/associola.c:651
sctp_sendmsg+0x35a5/0x4f90 net/sctp/socket.c:1871
inet_sendmsg+0x498/0x670 net/ipv4/af_inet.c:762
sock_sendmsg_nosec net/socket.c:633 [inline]
sock_sendmsg net/socket.c:643 [inline]
SYSC_sendto+0x608/0x710 net/socket.c:1696
SyS_sendto+0x8a/0xb0 net/socket.c:1664
entry_SYSCALL_64_fastpath+0x13/0x94
RIP: 0033:0x44b479
RSP: 002b:00007f6213f21c08 EFLAGS: 00000286 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 000000000044b479
RDX: 0000000000000041 RSI: 0000000020edd000 RDI: 0000000000000006
RBP: 00000000007080a8 R08: 0000000020b85fe4 R09: 000000000000001c
R10: 0000000000040005 R11: 0000000000000286 R12: 00000000ffffffff
R13: 0000000000003760 R14: 00000000006e5820 R15: 0000000000ff8000
origin description: ----dst_saddr@sctp_v6_get_dst
local variable created at:
sk_fullsock include/net/sock.h:2321 [inline]
inet6_sk include/linux/ipv6.h:309 [inline]
sctp_v6_get_dst+0x91/0x1630 net/sctp/ipv6.c:241
sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
==================================================================

Signed-off-by: Alexander Potapenko <[email protected]>
Reviewed-by: Xin Long <[email protected]>
---
v2 is identical to v1, resending per request by Marcelo Ricardo Leitner.
---
net/sctp/ipv6.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index 2a186b201ad2..a15d691829c6 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -513,6 +513,8 @@ static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr,
addr->sa.sa_family = AF_INET6;
addr->v6.sin6_port = port;
addr->v6.sin6_addr = *saddr;
+ addr->v6.sin6_flowinfo = 0;
+ addr->v6.sin6_scope_id = 0;
}

/* Compare addresses exactly.
--
2.14.0.434.g98096fd7a8-goog


2017-08-14 23:07:13

by Marcelo Ricardo Leitner

[permalink] [raw]
Subject: Re: [PATCH v2] sctp: fully initialize the IPv6 address in sctp_v6_to_addr()

On Mon, Aug 14, 2017 at 08:43:04PM +0200, Alexander Potapenko wrote:
> KMSAN reported use of uninitialized sctp_addr->v4.sin_addr.s_addr and
> sctp_addr->v6.sin6_scope_id in sctp_v6_cmp_addr() (see below).
> Make sure all fields of an IPv6 address are initialized, which
> guarantees that the IPv4 fields are also initialized.
>
> ==================================================================
> BUG: KMSAN: use of uninitialized memory in sctp_v6_cmp_addr+0x8d4/0x9f0
> net/sctp/ipv6.c:517
> CPU: 2 PID: 31056 Comm: syz-executor1 Not tainted 4.11.0-rc5+ #2944
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
> 01/01/2011
> Call Trace:
> dump_stack+0x172/0x1c0 lib/dump_stack.c:42
> is_logbuf_locked mm/kmsan/kmsan.c:59 [inline]
> kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:938
> native_save_fl arch/x86/include/asm/irqflags.h:18 [inline]
> arch_local_save_flags arch/x86/include/asm/irqflags.h:72 [inline]
> arch_local_irq_save arch/x86/include/asm/irqflags.h:113 [inline]
> __msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:467
> sctp_v6_cmp_addr+0x8d4/0x9f0 net/sctp/ipv6.c:517
> sctp_v6_get_dst+0x8c7/0x1630 net/sctp/ipv6.c:290
> sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
> sctp_assoc_add_peer+0x66d/0x16f0 net/sctp/associola.c:651
> sctp_sendmsg+0x35a5/0x4f90 net/sctp/socket.c:1871
> inet_sendmsg+0x498/0x670 net/ipv4/af_inet.c:762
> sock_sendmsg_nosec net/socket.c:633 [inline]
> sock_sendmsg net/socket.c:643 [inline]
> SYSC_sendto+0x608/0x710 net/socket.c:1696
> SyS_sendto+0x8a/0xb0 net/socket.c:1664
> entry_SYSCALL_64_fastpath+0x13/0x94
> RIP: 0033:0x44b479
> RSP: 002b:00007f6213f21c08 EFLAGS: 00000286 ORIG_RAX: 000000000000002c
> RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 000000000044b479
> RDX: 0000000000000041 RSI: 0000000020edd000 RDI: 0000000000000006
> RBP: 00000000007080a8 R08: 0000000020b85fe4 R09: 000000000000001c
> R10: 0000000000040005 R11: 0000000000000286 R12: 00000000ffffffff
> R13: 0000000000003760 R14: 00000000006e5820 R15: 0000000000ff8000
> origin description: ----dst_saddr@sctp_v6_get_dst
> local variable created at:
> sk_fullsock include/net/sock.h:2321 [inline]
> inet6_sk include/linux/ipv6.h:309 [inline]
> sctp_v6_get_dst+0x91/0x1630 net/sctp/ipv6.c:241
> sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
> ==================================================================
> BUG: KMSAN: use of uninitialized memory in sctp_v6_cmp_addr+0x8d4/0x9f0
> net/sctp/ipv6.c:517
> CPU: 2 PID: 31056 Comm: syz-executor1 Not tainted 4.11.0-rc5+ #2944
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
> 01/01/2011
> Call Trace:
> dump_stack+0x172/0x1c0 lib/dump_stack.c:42
> is_logbuf_locked mm/kmsan/kmsan.c:59 [inline]
> kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:938
> native_save_fl arch/x86/include/asm/irqflags.h:18 [inline]
> arch_local_save_flags arch/x86/include/asm/irqflags.h:72 [inline]
> arch_local_irq_save arch/x86/include/asm/irqflags.h:113 [inline]
> __msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:467
> sctp_v6_cmp_addr+0x8d4/0x9f0 net/sctp/ipv6.c:517
> sctp_v6_get_dst+0x8c7/0x1630 net/sctp/ipv6.c:290
> sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
> sctp_assoc_add_peer+0x66d/0x16f0 net/sctp/associola.c:651
> sctp_sendmsg+0x35a5/0x4f90 net/sctp/socket.c:1871
> inet_sendmsg+0x498/0x670 net/ipv4/af_inet.c:762
> sock_sendmsg_nosec net/socket.c:633 [inline]
> sock_sendmsg net/socket.c:643 [inline]
> SYSC_sendto+0x608/0x710 net/socket.c:1696
> SyS_sendto+0x8a/0xb0 net/socket.c:1664
> entry_SYSCALL_64_fastpath+0x13/0x94
> RIP: 0033:0x44b479
> RSP: 002b:00007f6213f21c08 EFLAGS: 00000286 ORIG_RAX: 000000000000002c
> RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 000000000044b479
> RDX: 0000000000000041 RSI: 0000000020edd000 RDI: 0000000000000006
> RBP: 00000000007080a8 R08: 0000000020b85fe4 R09: 000000000000001c
> R10: 0000000000040005 R11: 0000000000000286 R12: 00000000ffffffff
> R13: 0000000000003760 R14: 00000000006e5820 R15: 0000000000ff8000
> origin description: ----dst_saddr@sctp_v6_get_dst
> local variable created at:
> sk_fullsock include/net/sock.h:2321 [inline]
> inet6_sk include/linux/ipv6.h:309 [inline]
> sctp_v6_get_dst+0x91/0x1630 net/sctp/ipv6.c:241
> sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
> ==================================================================
>
> Signed-off-by: Alexander Potapenko <[email protected]>
> Reviewed-by: Xin Long <[email protected]>

Acked-by: Marcelo Ricardo Leitner <[email protected]>

> ---
> v2 is identical to v1, resending per request by Marcelo Ricardo Leitner.
> ---
> net/sctp/ipv6.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
> index 2a186b201ad2..a15d691829c6 100644
> --- a/net/sctp/ipv6.c
> +++ b/net/sctp/ipv6.c
> @@ -513,6 +513,8 @@ static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr,
> addr->sa.sa_family = AF_INET6;
> addr->v6.sin6_port = port;
> addr->v6.sin6_addr = *saddr;
> + addr->v6.sin6_flowinfo = 0;
> + addr->v6.sin6_scope_id = 0;
> }
>
> /* Compare addresses exactly.
> --
> 2.14.0.434.g98096fd7a8-goog
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-sctp" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>

2017-08-15 01:44:52

by Hideaki Yoshifuji

[permalink] [raw]
Subject: Re: [PATCH v2] sctp: fully initialize the IPv6 address in sctp_v6_to_addr()

Hi,

2017-08-15 3:43 GMT+09:00 Alexander Potapenko <[email protected]>:
> KMSAN reported use of uninitialized sctp_addr->v4.sin_addr.s_addr and
> sctp_addr->v6.sin6_scope_id in sctp_v6_cmp_addr() (see below).
> Make sure all fields of an IPv6 address are initialized, which
> guarantees that the IPv4 fields are also initialized.
>
> ==================================================================
> BUG: KMSAN: use of uninitialized memory in sctp_v6_cmp_addr+0x8d4/0x9f0
> net/sctp/ipv6.c:517
> CPU: 2 PID: 31056 Comm: syz-executor1 Not tainted 4.11.0-rc5+ #2944
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
> 01/01/2011
> Call Trace:
> dump_stack+0x172/0x1c0 lib/dump_stack.c:42
> is_logbuf_locked mm/kmsan/kmsan.c:59 [inline]
> kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:938
> native_save_fl arch/x86/include/asm/irqflags.h:18 [inline]
> arch_local_save_flags arch/x86/include/asm/irqflags.h:72 [inline]
> arch_local_irq_save arch/x86/include/asm/irqflags.h:113 [inline]
> __msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:467
> sctp_v6_cmp_addr+0x8d4/0x9f0 net/sctp/ipv6.c:517
> sctp_v6_get_dst+0x8c7/0x1630 net/sctp/ipv6.c:290
> sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
> sctp_assoc_add_peer+0x66d/0x16f0 net/sctp/associola.c:651
> sctp_sendmsg+0x35a5/0x4f90 net/sctp/socket.c:1871
> inet_sendmsg+0x498/0x670 net/ipv4/af_inet.c:762
> sock_sendmsg_nosec net/socket.c:633 [inline]
> sock_sendmsg net/socket.c:643 [inline]
> SYSC_sendto+0x608/0x710 net/socket.c:1696
> SyS_sendto+0x8a/0xb0 net/socket.c:1664
> entry_SYSCALL_64_fastpath+0x13/0x94
> RIP: 0033:0x44b479
> RSP: 002b:00007f6213f21c08 EFLAGS: 00000286 ORIG_RAX: 000000000000002c
> RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 000000000044b479
> RDX: 0000000000000041 RSI: 0000000020edd000 RDI: 0000000000000006
> RBP: 00000000007080a8 R08: 0000000020b85fe4 R09: 000000000000001c
> R10: 0000000000040005 R11: 0000000000000286 R12: 00000000ffffffff
> R13: 0000000000003760 R14: 00000000006e5820 R15: 0000000000ff8000
> origin description: ----dst_saddr@sctp_v6_get_dst
> local variable created at:
> sk_fullsock include/net/sock.h:2321 [inline]
> inet6_sk include/linux/ipv6.h:309 [inline]
> sctp_v6_get_dst+0x91/0x1630 net/sctp/ipv6.c:241
> sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
> ==================================================================
> BUG: KMSAN: use of uninitialized memory in sctp_v6_cmp_addr+0x8d4/0x9f0
> net/sctp/ipv6.c:517
> CPU: 2 PID: 31056 Comm: syz-executor1 Not tainted 4.11.0-rc5+ #2944
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
> 01/01/2011
> Call Trace:
> dump_stack+0x172/0x1c0 lib/dump_stack.c:42
> is_logbuf_locked mm/kmsan/kmsan.c:59 [inline]
> kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:938
> native_save_fl arch/x86/include/asm/irqflags.h:18 [inline]
> arch_local_save_flags arch/x86/include/asm/irqflags.h:72 [inline]
> arch_local_irq_save arch/x86/include/asm/irqflags.h:113 [inline]
> __msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:467
> sctp_v6_cmp_addr+0x8d4/0x9f0 net/sctp/ipv6.c:517
> sctp_v6_get_dst+0x8c7/0x1630 net/sctp/ipv6.c:290
> sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
> sctp_assoc_add_peer+0x66d/0x16f0 net/sctp/associola.c:651
> sctp_sendmsg+0x35a5/0x4f90 net/sctp/socket.c:1871
> inet_sendmsg+0x498/0x670 net/ipv4/af_inet.c:762
> sock_sendmsg_nosec net/socket.c:633 [inline]
> sock_sendmsg net/socket.c:643 [inline]
> SYSC_sendto+0x608/0x710 net/socket.c:1696
> SyS_sendto+0x8a/0xb0 net/socket.c:1664
> entry_SYSCALL_64_fastpath+0x13/0x94
> RIP: 0033:0x44b479
> RSP: 002b:00007f6213f21c08 EFLAGS: 00000286 ORIG_RAX: 000000000000002c
> RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 000000000044b479
> RDX: 0000000000000041 RSI: 0000000020edd000 RDI: 0000000000000006
> RBP: 00000000007080a8 R08: 0000000020b85fe4 R09: 000000000000001c
> R10: 0000000000040005 R11: 0000000000000286 R12: 00000000ffffffff
> R13: 0000000000003760 R14: 00000000006e5820 R15: 0000000000ff8000
> origin description: ----dst_saddr@sctp_v6_get_dst
> local variable created at:
> sk_fullsock include/net/sock.h:2321 [inline]
> inet6_sk include/linux/ipv6.h:309 [inline]
> sctp_v6_get_dst+0x91/0x1630 net/sctp/ipv6.c:241
> sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
> ==================================================================
>
> Signed-off-by: Alexander Potapenko <[email protected]>
> Reviewed-by: Xin Long <[email protected]>
> ---
> v2 is identical to v1, resending per request by Marcelo Ricardo Leitner.
> ---
> net/sctp/ipv6.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
> index 2a186b201ad2..a15d691829c6 100644
> --- a/net/sctp/ipv6.c
> +++ b/net/sctp/ipv6.c
> @@ -513,6 +513,8 @@ static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr,
> addr->sa.sa_family = AF_INET6;
> addr->v6.sin6_port = port;
> addr->v6.sin6_addr = *saddr;
> + addr->v6.sin6_flowinfo = 0;
> + addr->v6.sin6_scope_id = 0;

Please set flowinfo between port and addr.

--yoshfuji

> }
>
> /* Compare addresses exactly.
> --
> 2.14.0.434.g98096fd7a8-goog
>

2017-08-15 01:58:36

by Marcelo Ricardo Leitner

[permalink] [raw]
Subject: Re: [PATCH v2] sctp: fully initialize the IPv6 address in sctp_v6_to_addr()

On Tue, Aug 15, 2017 at 10:43:59AM +0900, 吉藤英明 wrote:
> Hi,
>
> 2017-08-15 3:43 GMT+09:00 Alexander Potapenko <[email protected]>:
> > KMSAN reported use of uninitialized sctp_addr->v4.sin_addr.s_addr and
> > sctp_addr->v6.sin6_scope_id in sctp_v6_cmp_addr() (see below).
> > Make sure all fields of an IPv6 address are initialized, which
> > guarantees that the IPv4 fields are also initialized.
> >
> > ==================================================================
> > BUG: KMSAN: use of uninitialized memory in sctp_v6_cmp_addr+0x8d4/0x9f0
> > net/sctp/ipv6.c:517
> > CPU: 2 PID: 31056 Comm: syz-executor1 Not tainted 4.11.0-rc5+ #2944
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
> > 01/01/2011
> > Call Trace:
> > dump_stack+0x172/0x1c0 lib/dump_stack.c:42
> > is_logbuf_locked mm/kmsan/kmsan.c:59 [inline]
> > kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:938
> > native_save_fl arch/x86/include/asm/irqflags.h:18 [inline]
> > arch_local_save_flags arch/x86/include/asm/irqflags.h:72 [inline]
> > arch_local_irq_save arch/x86/include/asm/irqflags.h:113 [inline]
> > __msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:467
> > sctp_v6_cmp_addr+0x8d4/0x9f0 net/sctp/ipv6.c:517
> > sctp_v6_get_dst+0x8c7/0x1630 net/sctp/ipv6.c:290
> > sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
> > sctp_assoc_add_peer+0x66d/0x16f0 net/sctp/associola.c:651
> > sctp_sendmsg+0x35a5/0x4f90 net/sctp/socket.c:1871
> > inet_sendmsg+0x498/0x670 net/ipv4/af_inet.c:762
> > sock_sendmsg_nosec net/socket.c:633 [inline]
> > sock_sendmsg net/socket.c:643 [inline]
> > SYSC_sendto+0x608/0x710 net/socket.c:1696
> > SyS_sendto+0x8a/0xb0 net/socket.c:1664
> > entry_SYSCALL_64_fastpath+0x13/0x94
> > RIP: 0033:0x44b479
> > RSP: 002b:00007f6213f21c08 EFLAGS: 00000286 ORIG_RAX: 000000000000002c
> > RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 000000000044b479
> > RDX: 0000000000000041 RSI: 0000000020edd000 RDI: 0000000000000006
> > RBP: 00000000007080a8 R08: 0000000020b85fe4 R09: 000000000000001c
> > R10: 0000000000040005 R11: 0000000000000286 R12: 00000000ffffffff
> > R13: 0000000000003760 R14: 00000000006e5820 R15: 0000000000ff8000
> > origin description: ----dst_saddr@sctp_v6_get_dst
> > local variable created at:
> > sk_fullsock include/net/sock.h:2321 [inline]
> > inet6_sk include/linux/ipv6.h:309 [inline]
> > sctp_v6_get_dst+0x91/0x1630 net/sctp/ipv6.c:241
> > sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
> > ==================================================================
> > BUG: KMSAN: use of uninitialized memory in sctp_v6_cmp_addr+0x8d4/0x9f0
> > net/sctp/ipv6.c:517
> > CPU: 2 PID: 31056 Comm: syz-executor1 Not tainted 4.11.0-rc5+ #2944
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
> > 01/01/2011
> > Call Trace:
> > dump_stack+0x172/0x1c0 lib/dump_stack.c:42
> > is_logbuf_locked mm/kmsan/kmsan.c:59 [inline]
> > kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:938
> > native_save_fl arch/x86/include/asm/irqflags.h:18 [inline]
> > arch_local_save_flags arch/x86/include/asm/irqflags.h:72 [inline]
> > arch_local_irq_save arch/x86/include/asm/irqflags.h:113 [inline]
> > __msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:467
> > sctp_v6_cmp_addr+0x8d4/0x9f0 net/sctp/ipv6.c:517
> > sctp_v6_get_dst+0x8c7/0x1630 net/sctp/ipv6.c:290
> > sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
> > sctp_assoc_add_peer+0x66d/0x16f0 net/sctp/associola.c:651
> > sctp_sendmsg+0x35a5/0x4f90 net/sctp/socket.c:1871
> > inet_sendmsg+0x498/0x670 net/ipv4/af_inet.c:762
> > sock_sendmsg_nosec net/socket.c:633 [inline]
> > sock_sendmsg net/socket.c:643 [inline]
> > SYSC_sendto+0x608/0x710 net/socket.c:1696
> > SyS_sendto+0x8a/0xb0 net/socket.c:1664
> > entry_SYSCALL_64_fastpath+0x13/0x94
> > RIP: 0033:0x44b479
> > RSP: 002b:00007f6213f21c08 EFLAGS: 00000286 ORIG_RAX: 000000000000002c
> > RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 000000000044b479
> > RDX: 0000000000000041 RSI: 0000000020edd000 RDI: 0000000000000006
> > RBP: 00000000007080a8 R08: 0000000020b85fe4 R09: 000000000000001c
> > R10: 0000000000040005 R11: 0000000000000286 R12: 00000000ffffffff
> > R13: 0000000000003760 R14: 00000000006e5820 R15: 0000000000ff8000
> > origin description: ----dst_saddr@sctp_v6_get_dst
> > local variable created at:
> > sk_fullsock include/net/sock.h:2321 [inline]
> > inet6_sk include/linux/ipv6.h:309 [inline]
> > sctp_v6_get_dst+0x91/0x1630 net/sctp/ipv6.c:241
> > sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
> > ==================================================================
> >
> > Signed-off-by: Alexander Potapenko <[email protected]>
> > Reviewed-by: Xin Long <[email protected]>
> > ---
> > v2 is identical to v1, resending per request by Marcelo Ricardo Leitner.
> > ---
> > net/sctp/ipv6.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
> > index 2a186b201ad2..a15d691829c6 100644
> > --- a/net/sctp/ipv6.c
> > +++ b/net/sctp/ipv6.c
> > @@ -513,6 +513,8 @@ static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr,
> > addr->sa.sa_family = AF_INET6;
> > addr->v6.sin6_port = port;
> > addr->v6.sin6_addr = *saddr;
> > + addr->v6.sin6_flowinfo = 0;
> > + addr->v6.sin6_scope_id = 0;
>
> Please set flowinfo between port and addr.

Why?

>
> --yoshfuji
>
> > }
> >
> > /* Compare addresses exactly.
> > --
> > 2.14.0.434.g98096fd7a8-goog
> >
> --
> To unsubscribe from this list: send the line "unsubscribe linux-sctp" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>

2017-08-15 02:40:56

by David Miller

[permalink] [raw]
Subject: Re: [PATCH v2] sctp: fully initialize the IPv6 address in sctp_v6_to_addr()

From: Marcelo Ricardo Leitner <[email protected]>
Date: Mon, 14 Aug 2017 22:58:14 -0300

> On Tue, Aug 15, 2017 at 10:43:59AM +0900, $B5HF#1QL@(B wrote:
>> > diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
>> > index 2a186b201ad2..a15d691829c6 100644
>> > --- a/net/sctp/ipv6.c
>> > +++ b/net/sctp/ipv6.c
>> > @@ -513,6 +513,8 @@ static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr,
>> > addr->sa.sa_family = AF_INET6;
>> > addr->v6.sin6_port = port;
>> > addr->v6.sin6_addr = *saddr;
>> > + addr->v6.sin6_flowinfo = 0;
>> > + addr->v6.sin6_scope_id = 0;
>>
>> Please set flowinfo between port and addr.
>
> Why?

Store buffer compression.

You want to always initialize structure member in the order
they are in memory.

No, the compiler won't do this automatically.

2017-08-15 15:06:06

by Marcelo Ricardo Leitner

[permalink] [raw]
Subject: Re: [PATCH v2] sctp: fully initialize the IPv6 address in sctp_v6_to_addr()

On Mon, Aug 14, 2017 at 07:40:51PM -0700, David Miller wrote:
> From: Marcelo Ricardo Leitner <[email protected]>
> Date: Mon, 14 Aug 2017 22:58:14 -0300
>
> > On Tue, Aug 15, 2017 at 10:43:59AM +0900, 吉藤英明 wrote:
> >> > diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
> >> > index 2a186b201ad2..a15d691829c6 100644
> >> > --- a/net/sctp/ipv6.c
> >> > +++ b/net/sctp/ipv6.c
> >> > @@ -513,6 +513,8 @@ static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr,
> >> > addr->sa.sa_family = AF_INET6;
> >> > addr->v6.sin6_port = port;
> >> > addr->v6.sin6_addr = *saddr;
> >> > + addr->v6.sin6_flowinfo = 0;
> >> > + addr->v6.sin6_scope_id = 0;
> >>
> >> Please set flowinfo between port and addr.
> >
> > Why?
>
> Store buffer compression.
>
> You want to always initialize structure member in the order
> they are in memory.

Thanks.

>
> No, the compiler won't do this automatically.

Ok, but I should see a difference in the generated code, right?

union sctp_addr is a union of sockaddr_in structs, for easy reference
ipv6 being:
struct sockaddr_in6 {
short unsigned int sin6_family; /* 0 2 */
__be16 sin6_port; /* 2 2 */
__be32 sin6_flowinfo; /* 4 4 */
struct in6_addr sin6_addr; /* 8 16 */
__u32 sin6_scope_id; /* 24 4 */

Current code:
12a1: ba 0a 00 00 00 mov $0xa,%edx
12a6: 49 8b 5f 68 mov 0x68(%r15),%rbx
12aa: 66 89 55 a0 mov %dx,-0x60(%rbp)
union/struct start -----^
12ae: 4d 8d 4f 68 lea 0x68(%r15),%r9
12b2: 49 8b 55 40 mov 0x40(%r13),%rdx
12b6: 66 c1 c0 08 rol $0x8,%ax (htons)
12ba: 4c 39 cb cmp %r9,%rbx
12bd: 48 89 55 b0 mov %rdx,-0x50(%rbp)
thus this ---^
12c1: 66 89 45 a2 mov %ax,-0x5e(%rbp)
^-------- port number
12c5: 49 8b 45 38 mov 0x38(%r13),%rax
12c9: 48 89 45 a8 mov %rax,-0x58(%rbp)
and this are the ipv6 addr bytes ---^
12cd: 74 30 je 12ff <sctp_v6_get_dst+0x37f>

Alexander's:
12a1: ba 0a 00 00 00 mov $0xa,%edx
12a6: 49 8b 5f 68 mov 0x68(%r15),%rbx
12aa: 66 89 55 a0 mov %dx,-0x60(%rbp)
12ae: 4d 8d 4f 68 lea 0x68(%r15),%r9
12b2: 49 8b 55 40 mov 0x40(%r13),%rdx
12b6: c7 45 a4 00 00 00 00 movl $0x0,-0x5c(%rbp)
12bd: c7 45 b8 00 00 00 00 movl $0x0,-0x48(%rbp)
12c4: 66 c1 c0 08 rol $0x8,%ax
12c8: 4c 39 cb cmp %r9,%rbx
12cb: 48 89 55 b0 mov %rdx,-0x50(%rbp)
12cf: 66 89 45 a2 mov %ax,-0x5e(%rbp)
12d3: 49 8b 45 38 mov 0x38(%r13),%rax
12d7: 48 89 45 a8 mov %rax,-0x58(%rbp)
12db: 74 30 je 130d <sctp_v6_get_dst+0x38d>

Hideaki's:
12a1: ba 0a 00 00 00 mov $0xa,%edx
12a6: 49 8b 5f 68 mov 0x68(%r15),%rbx
12aa: 66 89 55 a0 mov %dx,-0x60(%rbp)
12ae: 4d 8d 4f 68 lea 0x68(%r15),%r9
12b2: 49 8b 55 40 mov 0x40(%r13),%rdx
12b6: c7 45 a4 00 00 00 00 movl $0x0,-0x5c(%rbp)
12bd: c7 45 b8 00 00 00 00 movl $0x0,-0x48(%rbp)
12c4: 66 c1 c0 08 rol $0x8,%ax
12c8: 4c 39 cb cmp %r9,%rbx
12cb: 48 89 55 b0 mov %rdx,-0x50(%rbp)
12cf: 66 89 45 a2 mov %ax,-0x5e(%rbp)
12d3: 49 8b 45 38 mov 0x38(%r13),%rax
12d7: 48 89 45 a8 mov %rax,-0x58(%rbp)
12db: 74 30 je 130d <sctp_v6_get_dst+0x38d>

They are the same, and messed up by the compiler breaking the copy of
the ipv6 addr (which was copied backwards) with the port number copy.

Marcelo

2017-08-15 15:37:57

by Eric Dumazet

[permalink] [raw]
Subject: Re: [PATCH v2] sctp: fully initialize the IPv6 address in sctp_v6_to_addr()

On Tue, 2017-08-15 at 12:05 -0300, Marcelo Ricardo Leitner wrote:

> Ok, but I should see a difference in the generated code, right?

Depends on the compiler. Have you tried older versions ?

One argument is that following struct member definition eases code
review.

(It is easier to catch a field init is missing)


2017-08-15 16:31:50

by Marcelo Ricardo Leitner

[permalink] [raw]
Subject: Re: [PATCH v2] sctp: fully initialize the IPv6 address in sctp_v6_to_addr()

On Tue, Aug 15, 2017 at 08:37:49AM -0700, Eric Dumazet wrote:
> On Tue, 2017-08-15 at 12:05 -0300, Marcelo Ricardo Leitner wrote:
>
> > Ok, but I should see a difference in the generated code, right?
>
> Depends on the compiler. Have you tried older versions ?
>

This was with gcc 6.4.1, fc25 standard. Only tested with it and didn't
check clang either.

> One argument is that following struct member definition eases code
> review.
>
> (It is easier to catch a field init is missing)

And a good one, yes.

Thanks,
Marcelo