687775cec0
syzbot was able to trigger this trace [1], probably by using a zero optlen. While we are at it, cap optlen to IFNAMSIZ - 1 instead of IFNAMSIZ. [1] BUG: KMSAN: uninit-value in strnlen+0xf9/0x170 lib/string.c:569 CPU: 0 PID: 8807 Comm: syz-executor483 Not tainted 5.7.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x220 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215 strnlen+0xf9/0x170 lib/string.c:569 dev_name_hash net/core/dev.c:207 [inline] netdev_name_node_lookup net/core/dev.c:277 [inline] __dev_get_by_name+0x75/0x2b0 net/core/dev.c:778 ax25_setsockopt+0xfa3/0x1170 net/ax25/af_ax25.c:654 __compat_sys_setsockopt+0x4ed/0x910 net/compat.c:403 __do_compat_sys_setsockopt net/compat.c:413 [inline] __se_compat_sys_setsockopt+0xdd/0x100 net/compat.c:410 __ia32_compat_sys_setsockopt+0x62/0x80 net/compat.c:410 do_syscall_32_irqs_on arch/x86/entry/common.c:339 [inline] do_fast_syscall_32+0x3bf/0x6d0 arch/x86/entry/common.c:398 entry_SYSENTER_compat+0x68/0x77 arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f57dd9 Code: 90 e8 0b 00 00 00 f3 90 0f ae e8 eb f9 8d 74 26 00 89 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000ffae8c1c EFLAGS: 00000217 ORIG_RAX: 000000000000016e RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000000101 RDX: 0000000000000019 RSI: 0000000020000000 RDI: 0000000000000004 RBP: 0000000000000012 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Local variable ----devname@ax25_setsockopt created at: ax25_setsockopt+0xe6/0x1170 net/ax25/af_ax25.c:536 ax25_setsockopt+0xe6/0x1170 net/ax25/af_ax25.c:536 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.