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sctp: fully initialize the IPv6 address in sctp_v6_to_addr()

PATCH Superseded Alexander Potapenko 5 participants 8 messages Aug 14, 2017 – Aug 15, 2017

Subsystems (3)
Networking Network drivers SCTP protocol

v2 of 3 Superseded Latest is v3 →

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Alexander Potapenko

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#0 lore raw

PATCH v2 1/1 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(+)
net/sctp/ipv6.c +2 -0
index 2a186b201ad2..a15d691829c6 100644
@@ -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.
Signature · 1 line
2.14.0.434.g98096fd7a8-goog
maintainer Acked-by on v2 1/1
#1 lore raw
Quoted 83 lines · Alexander Potapenko

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
=================================
Quoted 2 lines
Signed-off-by Alexander Potapenko <[email protected]>
Reviewed-by Xin Long <[email protected]>
Acked-by Marcelo Ricardo Leitner <[email protected]>
Quoted 27 lines

---
v2 is identical to v1, resending per request by Marcelo Ricardo Leitner.

---
 net/sctp/ipv6.c | 2 ++
 1 file changed, 2 insertions(+)
net/sctp/ipv6.c +2 -0
index 2a186b201ad2..a15d691829c6 100644
@@ -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.
Signature · 6 lines
2.14.0.434.g98096fd7a8-goog

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#2 lore raw
In reply to Alexander Potapenko

Hi,

2017-08-15 3:43 GMT+09:00 Alexander Potapenko <[email protected]>:

Quoted 96 lines

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(+)
net/sctp/ipv6.c +0 -0
index 2a186b201ad2..a15d691829c6 100644

net/sctp/ipv6.c static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr, · line 517

Quoted 5 lines
net/sctp/ipv6.c +2 -0
@@ -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

Quoted 6 lines
net/sctp/ipv6.c +0 -1
 }
 
 /* Compare addresses exactly.
--

2.14.0.434.g98096fd7a8-goog

maintainer
#3 lore raw
Quoted 94 lines · 吉藤英明

Hi,

2017-08-15 3:43 GMT+09:00 Alexander Potapenko <[email protected]>:

Quoted 91 lines

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(+)
Quoted 12 lines

net/sctp/ipv6.c static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr, · line 517

Quoted 10 lines
net/sctp/ipv6.c +2 -0
index 2a186b201ad2..a15d691829c6 100644
@@ -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?

Quoted 14 lines

--yoshfuji

Quoted 6 lines
net/sctp/ipv6.c +0 -1
 }
 
 /* Compare addresses exactly.
--

2.14.0.434.g98096fd7a8-goog

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maintainer
#4 lore raw

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

Quoted 14 lines · 吉藤英明
Quoted 4 lines
Quoted 4 lines
net/sctp/ipv6.c +0 -0
index 2a186b201ad2..a15d691829c6 100644
Quoted 8 lines

net/sctp/ipv6.c static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr, · line 517

Quoted 6 lines
net/sctp/ipv6.c +2 -0
@@ -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.

Quoted 1 line

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.

maintainer
#5 lore raw
Quoted 17 lines · David Miller

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

Quoted 14 lines · 吉藤英明
Quoted 12 lines

net/sctp/ipv6.c static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr, · line 517

Quoted 10 lines
net/sctp/ipv6.c +2 -0
index 2a186b201ad2..a15d691829c6 100644
@@ -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.

Quoted 6 lines
Quoted 1 line

Why?

Store buffer compression.

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

Thanks.

Quoted 2 lines

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

#6 lore raw
Quoted 1 line · Marcelo Ricardo Leitner

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)

maintainer
#7 lore raw
Quoted 6 lines · Eric Dumazet
Quoted 1 line · Marcelo Ricardo Leitner

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.

Quoted 4 lines

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