Kuniyuki Iwashima 06d4c8a808 af_unix: Fix fortify_panic() in unix_bind_bsd(). ... syzkaller found a bug in unix_bind_bsd() [0]. We can reproduce it by bind()ing a socket on a path with length 108. 108 is the size of sun_addr of struct sockaddr_un and is the maximum valid length for the pathname socket. When calling bind(), we use struct sockaddr_storage as the actual buffer size, so terminating sun_addr[108] with null is legitimate as done in unix_mkname_bsd(). However, strlen(sunaddr) for such a case causes fortify_panic() if CONFIG_FORTIFY_SOURCE=y. __fortify_strlen() has no idea about the actual buffer size and see the string as unterminated. Let's use strnlen() to allow sun_addr to be unterminated at 107. [0]: detected buffer overflow in __fortify_strlen kernel BUG at lib/string_helpers.c:1031! Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 255 Comm: syz-executor296 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 : fortify_panic+0x1c/0x20 lib/string_helpers.c:1030 lr : fortify_panic+0x1c/0x20 lib/string_helpers.c:1030 sp : ffff800089817af0 x29: ffff800089817af0 x28: ffff800089817b40 x27: 1ffff00011302f68 x26: 000000000000006e x25: 0000000000000012 x24: ffff800087e60140 x23: dfff800000000000 x22: ffff800089817c20 x21: ffff800089817c8e x20: 000000000000006c x19: ffff00000c323900 x18: ffff800086ab1630 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000001 x14: 1ffff00011302eb8 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : 64a26b65474d2a00 x8 : 64a26b65474d2a00 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff800089817438 x4 : ffff800086ac99e0 x3 : ffff800080f19e8c x2 : 0000000000000001 x1 : 0000000100000000 x0 : 000000000000002c Call trace: fortify_panic+0x1c/0x20 lib/string_helpers.c:1030 _Z16__fortify_strlenPKcU25pass_dynamic_object_size1 include/linux/fortify-string.h:217 [inline] unix_bind_bsd net/unix/af_unix.c:1212 [inline] unix_bind+0xba8/0xc58 net/unix/af_unix.c:1326 __sys_bind+0x1ac/0x248 net/socket.c:1792 __do_sys_bind net/socket.c:1803 [inline] __se_sys_bind net/socket.c:1801 [inline] __arm64_sys_bind+0x7c/0x94 net/socket.c:1801 __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 Code: aa0003e1 d0000e80 91030000 97ffc91a (d4210000) 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/20230724213425.22920-2-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
..
af_unix.c	af_unix: Fix fortify_panic() in unix_bind_bsd().	2023-07-25 20:10:05 -07:00
diag.c	af_unix: Get user_ns from in_skb in unix_diag_get_exact().	2022-12-01 10:32:20 +01:00
garbage.c	net: reclaim skb->scm_io_uring bit	2023-03-08 13:21:47 +00:00
Kconfig	af_unix: Kconfig: make CONFIG_UNIX bool	2023-06-12 10:45:50 +01:00
Makefile	af_unix: Implement ->psock_update_sk_prot()	2021-07-15 18:17:50 -07:00
scm.c	net: reclaim skb->scm_io_uring bit	2023-03-08 13:21:47 +00:00
scm.h	net: split out functions related to registering inflight socket files	2019-02-28 08:24:23 -07:00
sysctl_net_unix.c	af_unix: fix unix_sysctl_register() error path	2022-07-09 12:27:33 +01:00
unix_bpf.c	bpf, sockmap: Fix an infinite loop error when len is 0 in tcp_bpf_recvmsg_parser()	2023-03-03 17:25:15 +01:00