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bpf: Extend BTF_ID_LIST_GLOBAL with parameter for number of IDs 

syzbot reported the following BUG w/o CONFIG_DEBUG_INFO_BTF

BUG: KASAN: global-out-of-bounds in task_iter_init+0x212/0x2e7 kernel/bpf/task_iter.c:661
Read of size 4 at addr ffffffff90297404 by task swapper/0/1

CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.15.0-syzkaller #0
Hardware name: ... Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0xf/0x309 mm/kasan/report.c:256
__kasan_report mm/kasan/report.c:442 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
task_iter_init+0x212/0x2e7 kernel/bpf/task_iter.c:661
do_one_initcall+0x103/0x650 init/main.c:1295
do_initcall_level init/main.c:1368 [inline]
do_initcalls init/main.c:1384 [inline]
do_basic_setup init/main.c:1403 [inline]
kernel_init_freeable+0x6b1/0x73a init/main.c:1606
kernel_init+0x1a/0x1d0 init/main.c:1497
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>

This is caused by hard-coded name[1] in BTF_ID_LIST_GLOBAL (w/o
CONFIG_DEBUG_INFO_BTF). Fix this by adding a parameter n to
BTF_ID_LIST_GLOBAL. This avoids ifdef CONFIG_DEBUG_INFO_BTF in btf.c and
filter.c.

Fixes: 7c7e3d31e7 ("bpf: Introduce helper bpf_find_vma")
Reported-by: syzbot+e0d81ec552a21d9071aa@syzkaller.appspotmail.com
Reported-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20211112150243.1270987-2-songliubraving@fb.com
This commit is contained in:
Song Liu 2021-11-12 07:02:42 -08:00 committed by Alexei Starovoitov
parent 314f14abde
commit 9e2ad638ae
3 changed files with 5 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/linux/btf_ids.h
View File

@ -73,7 +73,7 @@ asm( \
__BTF_ID_LIST(name, local) \
extern u32 name[];
#define BTF_ID_LIST_GLOBAL(name) \
#define BTF_ID_LIST_GLOBAL(name, n) \
__BTF_ID_LIST(name, globl)
/* The BTF_ID_LIST_SINGLE macro defines a BTF_ID_LIST with
@ -83,7 +83,7 @@ __BTF_ID_LIST(name, globl)
BTF_ID_LIST(name) \
BTF_ID(prefix, typename)
#define BTF_ID_LIST_GLOBAL_SINGLE(name, prefix, typename) \
BTF_ID_LIST_GLOBAL(name) \
BTF_ID_LIST_GLOBAL(name, 1) \
BTF_ID(prefix, typename)
/*
@ -149,7 +149,7 @@ extern struct btf_id_set name;
#define BTF_ID_LIST(name) static u32 name[5];
#define BTF_ID(prefix, name)
#define BTF_ID_UNUSED
#define BTF_ID_LIST_GLOBAL(name) u32 name[1];
#define BTF_ID_LIST_GLOBAL(name, n) u32 name[n];
#define BTF_ID_LIST_SINGLE(name, prefix, typename) static u32 name[1];
#define BTF_ID_LIST_GLOBAL_SINGLE(name, prefix, typename) u32 name[1];
#define BTF_SET_START(name) static struct btf_id_set name = { 0 };

2
kernel/bpf/btf.c
View File

@ -6354,7 +6354,7 @@ const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
.arg4_type = ARG_ANYTHING,
};
BTF_ID_LIST_GLOBAL(btf_task_struct_ids)
BTF_ID_LIST_GLOBAL(btf_task_struct_ids, 3)
BTF_ID(struct, task_struct)
BTF_ID(struct, file)
BTF_ID(struct, vm_area_struct)

6
net/core/filter.c
View File

@ -10611,14 +10611,10 @@ void bpf_prog_change_xdp(struct bpf_prog *prev_prog, struct bpf_prog *prog)
bpf_dispatcher_change_prog(BPF_DISPATCHER_PTR(xdp), prev_prog, prog);
}
#ifdef CONFIG_DEBUG_INFO_BTF
BTF_ID_LIST_GLOBAL(btf_sock_ids)
BTF_ID_LIST_GLOBAL(btf_sock_ids, MAX_BTF_SOCK_TYPE)
#define BTF_SOCK_TYPE(name, type) BTF_ID(struct, type)
BTF_SOCK_TYPE_xxx
#undef BTF_SOCK_TYPE
#else
u32 btf_sock_ids[MAX_BTF_SOCK_TYPE];
#endif
BPF_CALL_1(bpf_skc_to_tcp6_sock, struct sock *, sk)
{