[PATCH v3] wifi: mac80211: Avoid address calculations via out of bounds array indexing
From: Kenton Groombridge
Date: Wed Jun 05 2024 - 11:23:48 EST
req->n_channels must be set before req->channels[] can be used.
This patch fixes one of the issues encountered in [1].
[ 83.964252] ------------[ cut here ]------------
[ 83.964255] UBSAN: array-index-out-of-bounds in net/mac80211/scan.c:364:4
[ 83.964258] index 0 is out of range for type 'struct ieee80211_channel *[]'
[ 83.964260] CPU: 0 PID: 1695 Comm: iwd Tainted: G O T 6.8.9-gentoo-hardened1 #1
[ 83.964262] Hardware name: System76 Pangolin/Pangolin, BIOS ARB928_V00.01_T0025ASY1_ms 04/20/2023
[ 83.964264] Call Trace:
[ 83.964267] <TASK>
[ 83.964269] dump_stack_lvl+0x3f/0xc0
[ 83.964274] __ubsan_handle_out_of_bounds+0xec/0x110
[ 83.964278] ieee80211_prep_hw_scan+0x2db/0x4b0
[ 83.964281] __ieee80211_start_scan+0x601/0x990
[ 83.964284] ? srso_alias_return_thunk+0x5/0xfbef5
[ 83.964287] ? cfg80211_scan+0x149/0x250
[ 83.964291] nl80211_trigger_scan+0x874/0x980
[ 83.964295] genl_family_rcv_msg_doit+0xe8/0x160
[ 83.964298] genl_rcv_msg+0x240/0x270
[ 83.964301] ? __cfi_nl80211_trigger_scan+0x10/0x10
[ 83.964302] ? __cfi_nl80211_post_doit+0x10/0x10
[ 83.964304] ? __cfi_nl80211_pre_doit+0x10/0x10
[ 83.964307] ? __cfi_genl_rcv_msg+0x10/0x10
[ 83.964309] netlink_rcv_skb+0x102/0x130
[ 83.964312] genl_rcv+0x23/0x40
[ 83.964314] netlink_unicast+0x23b/0x340
[ 83.964316] netlink_sendmsg+0x3a9/0x450
[ 83.964319] __sys_sendto+0x3ae/0x3c0
[ 83.964324] __x64_sys_sendto+0x21/0x40
[ 83.964326] do_syscall_64+0x90/0x150
[ 83.964329] ? srso_alias_return_thunk+0x5/0xfbef5
[ 83.964331] ? syscall_exit_work+0xc2/0xf0
[ 83.964333] ? srso_alias_return_thunk+0x5/0xfbef5
[ 83.964335] ? syscall_exit_to_user_mode+0x74/0xa0
[ 83.964337] ? srso_alias_return_thunk+0x5/0xfbef5
[ 83.964339] ? do_syscall_64+0x9c/0x150
[ 83.964340] ? srso_alias_return_thunk+0x5/0xfbef5
[ 83.964342] ? syscall_exit_to_user_mode+0x74/0xa0
[ 83.964344] ? srso_alias_return_thunk+0x5/0xfbef5
[ 83.964346] ? do_syscall_64+0x9c/0x150
[ 83.964347] ? srso_alias_return_thunk+0x5/0xfbef5
[ 83.964349] ? do_syscall_64+0x9c/0x150
[ 83.964351] ? srso_alias_return_thunk+0x5/0xfbef5
[ 83.964353] ? syscall_exit_work+0xc2/0xf0
[ 83.964354] ? srso_alias_return_thunk+0x5/0xfbef5
[ 83.964356] ? syscall_exit_to_user_mode+0x74/0xa0
[ 83.964358] ? srso_alias_return_thunk+0x5/0xfbef5
[ 83.964359] ? do_syscall_64+0x9c/0x150
[ 83.964361] ? srso_alias_return_thunk+0x5/0xfbef5
[ 83.964362] ? do_user_addr_fault+0x488/0x620
[ 83.964366] ? srso_alias_return_thunk+0x5/0xfbef5
[ 83.964367] ? srso_alias_return_thunk+0x5/0xfbef5
[ 83.964369] entry_SYSCALL_64_after_hwframe+0x55/0x5d
[ 83.964372] RIP: 0033:0x6200808578d7
[ 83.964374] Code: 00 00 90 f3 0f 1e fa 41 56 55 41 89 ce 48 83 ec 28 80 3d 7b f7 0d 00 00 74 29 45 31 c9 45 31 c0 41 89 ca b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 71 48 83 c4 28 5d 41 5e c3 66 0f 1f 84 00 00
[ 83.964375] RSP: 002b:0000730c4e821530 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[ 83.964378] RAX: ffffffffffffffda RBX: 000006dbc456c570 RCX: 00006200808578d7
[ 83.964379] RDX: 000000000000005c RSI: 000006dbc45884f0 RDI: 0000000000000004
[ 83.964381] RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
[ 83.964382] R10: 0000000000000000 R11: 0000000000000246 R12: 000006dbc456c480
[ 83.964383] R13: 000006dbc456c450 R14: 0000000000000000 R15: 000006dbc456c610
[ 83.964386] </TASK>
[ 83.964386] ---[ end trace ]---
[1] https://bugzilla.kernel.org/show_bug.cgi?id=218810
v3:
- Fix incorrect channel copying
v2:
- Drop changes in cfg80211 as requested by Johannes
Co-authored-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Kenton Groombridge <concord@xxxxxxxxxx>
---
net/mac80211/scan.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 73850312580f..56beed61d2b7 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -358,7 +358,8 @@ static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata)
struct cfg80211_scan_request *req;
struct cfg80211_chan_def chandef;
u8 bands_used = 0;
- int i, ielen, n_chans;
+ int i, ielen;
+ u32 *n_chans;
u32 flags = 0;
req = rcu_dereference_protected(local->scan_req,
@@ -368,34 +369,34 @@ static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata)
return false;
if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
+ local->hw_scan_req->req.n_channels = req->n_channels;
+
for (i = 0; i < req->n_channels; i++) {
local->hw_scan_req->req.channels[i] = req->channels[i];
bands_used |= BIT(req->channels[i]->band);
}
-
- n_chans = req->n_channels;
} else {
do {
if (local->hw_scan_band == NUM_NL80211_BANDS)
return false;
- n_chans = 0;
+ n_chans = &local->hw_scan_req->req.n_channels;
+ *n_chans = 0;
for (i = 0; i < req->n_channels; i++) {
if (req->channels[i]->band !=
local->hw_scan_band)
continue;
- local->hw_scan_req->req.channels[n_chans] =
+ local->hw_scan_req->req.channels[(*n_chans)++] =
req->channels[i];
- n_chans++;
+
bands_used |= BIT(req->channels[i]->band);
}
local->hw_scan_band++;
- } while (!n_chans);
+ } while (!*n_chans);
}
- local->hw_scan_req->req.n_channels = n_chans;
ieee80211_prepare_scan_chandef(&chandef);
if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
--
2.45.2