Subject: [syzbot] [wireless?] KASAN: slab-out-of-bounds Read in cfg80211_wext_freq

From: syzbot <[email-masked]>
Date: Wed, 29 May 2024 02:49:31 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    fda5695d692c Merge branch 'for-next/core' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=12be4768980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=95dc1de8407c7270
dashboard link: https://syzkaller.appspot.com/bug?extid=253cd2d2491df77c93ac
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15fc7784980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15505e8a980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/07f3214ff0d9/disk-fda5695d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/70e2e2c864e8/vmlinux-fda5695d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b259942a16dc/Image-fda5695d.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

warning: `syz-executor854' uses wireless extensions which will stop working for Wi-Fi 7 hardware; use nl80211
==================================================================
BUG: KASAN: slab-out-of-bounds in cfg80211_wext_freq+0x170/0x1ac net/wireless/wext-compat.c:238
Read of size 2 at addr ffff0000cd6ce140 by task syz-executor854/6234

CPU: 1 PID: 6234 Comm: syz-executor854 Not tainted 6.9.0-rc7-syzkaller-gfda5695d692c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call trace:
 dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:317
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:324
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x198/0x538 mm/kasan/report.c:488
 kasan_report+0xd8/0x138 mm/kasan/report.c:601
 __asan_report_load2_noabort+0x20/0x2c mm/kasan/report_generic.c:379
 cfg80211_wext_freq+0x170/0x1ac net/wireless/wext-compat.c:238
 cfg80211_wext_siwscan+0x438/0xef0 net/wireless/scan.c:3413
 ioctl_standard_iw_point+0x7f0/0xdc4 net/wireless/wext-core.c:867
 ioctl_standard_call+0xcc/0x264 net/wireless/wext-core.c:1052
 wext_ioctl_dispatch+0x1b4/0x534 net/wireless/wext-core.c:1016
 wext_handle_ioctl+0x1f8/0x3f4 net/wireless/wext-core.c:1077
 sock_ioctl+0x15c/0x838 net/socket.c:1275
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:904 [inline]
 __se_sys_ioctl fs/ioctl.c:890 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:890
 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

Allocated by task 6234:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_alloc_info+0x40/0x50 mm/kasan/generic.c:565
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0xac/0xc4 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slub.c:3966 [inline]
 __kmalloc+0x2b8/0x508 mm/slub.c:3979
 kmalloc include/linux/slab.h:632 [inline]
 kzalloc include/linux/slab.h:749 [inline]
 ioctl_standard_iw_point+0x3b8/0xdc4 net/wireless/wext-core.c:828
 ioctl_standard_call+0xcc/0x264 net/wireless/wext-core.c:1052
 wext_ioctl_dispatch+0x1b4/0x534 net/wireless/wext-core.c:1016
 wext_handle_ioctl+0x1f8/0x3f4 net/wireless/wext-core.c:1077
 sock_ioctl+0x15c/0x838 net/socket.c:1275
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:904 [inline]
 __se_sys_ioctl fs/ioctl.c:890 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:890
 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

The buggy address belongs to the object at ffff0000cd6ce000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 4 bytes to the right of
 allocated 316-byte region [ffff0000cd6ce000, ffff0000cd6ce13c)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10d6cc
head: order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x5ffc00000000840(slab|head|node=0|zone=2|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 05ffc00000000840 ffff0000c0001c80 fffffdffc335a900 dead000000000002
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
head: 05ffc00000000840 ffff0000c0001c80 fffffdffc335a900 dead000000000002
head: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
head: 05ffc00000000002 fffffdffc335b301 fffffdffc335b348 00000000ffffffff
head: 0000000400000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000cd6ce000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000cd6ce080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000cd6ce100: 00 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc
                                           ^
 ffff0000cd6ce180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000cd6ce200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in net/wireless/scan.c:3411:8
index 33 is out of range for type 'struct iw_freq[32]'
CPU: 1 PID: 6234 Comm: syz-executor854 Tainted: G    B              6.9.0-rc7-syzkaller-gfda5695d692c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call trace:
 dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:317
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:324
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:114
 dump_stack+0x1c/0x28 lib/dump_stack.c:123
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_out_of_bounds+0xf8/0x148 lib/ubsan.c:429
 cfg80211_wext_siwscan+0x4a8/0xef0 net/wireless/scan.c:3411
 ioctl_standard_iw_point+0x7f0/0xdc4 net/wireless/wext-core.c:867
 ioctl_standard_call+0xcc/0x264 net/wireless/wext-core.c:1052
 wext_ioctl_dispatch+0x1b4/0x534 net/wireless/wext-core.c:1016
 wext_handle_ioctl+0x1f8/0x3f4 net/wireless/wext-core.c:1077
 sock_ioctl+0x15c/0x838 net/socket.c:1275
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:904 [inline]
 __se_sys_ioctl fs/ioctl.c:890 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:890
 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
---[ end trace ]---

---
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