linux/include
Kuniyuki Iwashima a0ade8404c af_packet: Fix warning of fortified memcpy() in packet_getname().
syzkaller found a warning in packet_getname() [0], where we try to
copy 16 bytes to sockaddr_ll.sll_addr[8].

Some devices (ip6gre, vti6, ip6tnl) have 16 bytes address expressed
by struct in6_addr.  Also, Infiniband has 32 bytes as MAX_ADDR_LEN.

The write seems to overflow, but actually not since we use struct
sockaddr_storage defined in __sys_getsockname() and its size is 128
(_K_SS_MAXSIZE) bytes.  Thus, we have sufficient room after sll_addr[]
as __data[].

To avoid the warning, let's add a flex array member union-ed with
sll_addr.

Another option would be to use strncpy() and limit the copied length
to sizeof(sll_addr), but it will return the partial address and break
an application that passes sockaddr_storage to getsockname().

[0]:
memcpy: detected field-spanning write (size 16) of single field "sll->sll_addr" at net/packet/af_packet.c:3604 (size 8)
WARNING: CPU: 0 PID: 255 at net/packet/af_packet.c:3604 packet_getname+0x25c/0x3a0 net/packet/af_packet.c:3604
Modules linked in:
CPU: 0 PID: 255 Comm: syz-executor750 Not tainted 6.5.0-rc1-00330-g60cc1f7d0605 #4
Hardware name: linux,dummy-virt (DT)
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : packet_getname+0x25c/0x3a0 net/packet/af_packet.c:3604
lr : packet_getname+0x25c/0x3a0 net/packet/af_packet.c:3604
sp : ffff800089887bc0
x29: ffff800089887bc0 x28: ffff000010f80f80 x27: 0000000000000003
x26: dfff800000000000 x25: ffff700011310f80 x24: ffff800087d55000
x23: dfff800000000000 x22: ffff800089887c2c x21: 0000000000000010
x20: ffff00000de08310 x19: ffff800089887c20 x18: ffff800086ab1630
x17: 20646c6569662065 x16: 6c676e697320666f x15: 0000000000000001
x14: 1fffe0000d56d7ca x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000000 x9 : 3e60944c3da92b00
x8 : 3e60944c3da92b00 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff8000898874f8 x4 : ffff800086ac99e0 x3 : ffff8000803f8808
x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000000
Call trace:
 packet_getname+0x25c/0x3a0 net/packet/af_packet.c:3604
 __sys_getsockname+0x168/0x24c net/socket.c:2042
 __do_sys_getsockname net/socket.c:2057 [inline]
 __se_sys_getsockname net/socket.c:2054 [inline]
 __arm64_sys_getsockname+0x7c/0x94 net/socket.c:2054
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x134/0x240 arch/arm64/kernel/syscall.c:139
 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:188
 el0_svc+0x2c/0x7c arch/arm64/kernel/entry-common.c:647
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:665
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591

Fixes: df8fc4e934 ("kbuild: Enable -fstrict-flex-arrays=3")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230724213425.22920-3-kuniyu@amazon.com
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-07-25 20:10:05 -07:00
..
acpi More ACPI updates for 6.5-rc1 2023-07-06 22:25:06 -07:00
asm-generic vmlinux.lds.h: Remove a reference to no longer used sections .text..refcount 2023-07-11 14:29:43 -07:00
clocksource
crypto This update includes the following changes: 2023-06-30 21:27:13 -07:00
drm Linux 6.5-rc1 2023-07-11 09:23:20 +02:00
dt-bindings Another set of clk driver updates and fixes for the merge window. The 2023-07-04 11:07:45 -07:00
keys KEYS: Add forward declaration in asymmetric-parser.h 2023-06-23 16:15:37 +08:00
kunit
kvm Common KVM changes for 6.5: 2023-07-01 07:07:55 -04:00
linux Including fixes from BPF, netfilter, bluetooth and CAN. 2023-07-20 14:46:39 -07:00
math-emu
media media updates for v6.5-rc1 2023-07-05 10:42:32 -07:00
memory
misc
net tcp: Reduce chance of collisions in inet6_hashfn(). 2023-07-24 16:52:37 -07:00
pcmcia
ras
rdma rdma: fix INFINIBAND_USER_ACCESS dependency 2023-07-03 16:55:04 -07:00
rv
scsi SCSI misc on 20230629 2023-06-30 11:57:07 -07:00
soc net: dsa: felix: make vsc9959_tas_guard_bands_update() visible to ocelot->ops 2023-07-06 19:10:22 -07:00
sound ASoC: Updates for v6.5 2023-06-26 15:38:02 +02:00
target SCSI misc on 20230629 2023-06-30 11:57:07 -07:00
trace Including fixes from bluetooth, bpf and wireguard. 2023-07-05 15:44:45 -07:00
uapi af_packet: Fix warning of fortified memcpy() in packet_getname(). 2023-07-25 20:10:05 -07:00
ufs Merge branch '6.5/scsi-staging' into 6.5/scsi-fixes 2023-07-11 12:15:15 -04:00
vdso
video sticon/parisc: Fix STI console on 64-bit only machines 2023-06-30 17:14:14 +02:00
xen x86: xen: add missing prototypes 2023-06-26 07:47:11 +02:00