8007e40a24
The index is off-by-one when fp->aux->stack_depth has already been rounded up to 32. In particular, if stack_depth is 512, the index will be 16. The fix is to round_up and then takes -1 instead of round_down. [ 22.318680] ================================================================== [ 22.319745] BUG: KASAN: global-out-of-bounds in bpf_prog_select_runtime+0x48a/0x670 [ 22.320737] Read of size 8 at addr ffffffff82aadae0 by task sockex3/1946 [ 22.321646] [ 22.321858] CPU: 1 PID: 1946 Comm: sockex3 Tainted: G W 4.12.0-rc6-01680-g2ee87db3a287 #22 [ 22.323061] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-1.el7.centos 04/01/2014 [ 22.324260] Call Trace: [ 22.324612] dump_stack+0x67/0x99 [ 22.325081] print_address_description+0x1e8/0x290 [ 22.325734] ? bpf_prog_select_runtime+0x48a/0x670 [ 22.326360] kasan_report+0x265/0x350 [ 22.326860] __asan_report_load8_noabort+0x19/0x20 [ 22.327484] bpf_prog_select_runtime+0x48a/0x670 [ 22.328109] bpf_prog_load+0x626/0xd40 [ 22.328637] ? __bpf_prog_charge+0xc0/0xc0 [ 22.329222] ? check_nnp_nosuid.isra.61+0x100/0x100 [ 22.329890] ? __might_fault+0xf6/0x1b0 [ 22.330446] ? lock_acquire+0x360/0x360 [ 22.331013] SyS_bpf+0x67c/0x24d0 [ 22.331491] ? trace_hardirqs_on+0xd/0x10 [ 22.332049] ? __getnstimeofday64+0xaf/0x1c0 [ 22.332635] ? bpf_prog_get+0x20/0x20 [ 22.333135] ? __audit_syscall_entry+0x300/0x600 [ 22.333770] ? syscall_trace_enter+0x540/0xdd0 [ 22.334339] ? exit_to_usermode_loop+0xe0/0xe0 [ 22.334950] ? do_syscall_64+0x48/0x410 [ 22.335446] ? bpf_prog_get+0x20/0x20 [ 22.335954] do_syscall_64+0x181/0x410 [ 22.336454] entry_SYSCALL64_slow_path+0x25/0x25 [ 22.337121] RIP: 0033:0x7f263fe81f19 [ 22.337618] RSP: 002b:00007ffd9a3440c8 EFLAGS: 00000202 ORIG_RAX: 0000000000000141 [ 22.338619] RAX: ffffffffffffffda RBX: 0000000000aac5fb RCX: 00007f263fe81f19 [ 22.339600] RDX: 0000000000000030 RSI: 00007ffd9a3440d0 RDI: 0000000000000005 [ 22.340470] RBP: 0000000000a9a1e0 R08: 0000000000a9a1e0 R09: 0000009d00000001 [ 22.341430] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000010000 [ 22.342411] R13: 0000000000a9a023 R14: 0000000000000001 R15: 0000000000000003 [ 22.343369] [ 22.343593] The buggy address belongs to the variable: [ 22.344241] interpreters+0x80/0x980 [ 22.344708] [ 22.344908] Memory state around the buggy address: [ 22.345556] ffffffff82aad980: 00 00 00 04 fa fa fa fa 04 fa fa fa fa fa fa fa [ 22.346449] ffffffff82aada00: 00 00 00 00 00 fa fa fa fa fa fa fa 00 00 00 00 [ 22.347361] >ffffffff82aada80: 00 00 00 00 00 00 00 00 00 00 00 00 fa fa fa fa [ 22.348301] ^ [ 22.349142] ffffffff82aadb00: 00 01 fa fa fa fa fa fa 00 00 00 00 00 00 00 00 [ 22.350058] ffffffff82aadb80: 00 00 07 fa fa fa fa fa 00 00 05 fa fa fa fa fa [ 22.350984] ================================================================== Fixes: b870aa901f4b ("bpf: use different interpreter depending on required stack size") Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.