Messages in this thread | | | Date | Wed, 7 Feb 2024 11:36:31 -0600 | Subject | Re: [PATCH v3] wifi: mwifiex: Refactor 1-element array into flexible array in struct mwifiex_ie_types_chan_list_param_set | From | "Gustavo A. R. Silva" <> |
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On 2/7/24 04:30, Kees Cook wrote: > struct mwifiex_ie_types_chan_list_param_set::chan_scan_param is treated > as a flexible array, so convert it into one so that it doesn't trip > the array bounds sanitizer[1]. Only a few places were using sizeof() > on the whole struct, so adjust those to follow the calculation pattern > to avoid including the trailing single element. > > Examining binary output differences doesn't appear to show any literal > size values changing, though it is obfuscated a bit by the compiler > adjusting register usage and stack spill slots, etc. > > Link: https://github.com/KSPP/linux/issues/51 [1] > Cc: Brian Norris <briannorris@chromium.org> > Cc: Kalle Valo <kvalo@kernel.org> > Cc: Dmitry Antipov <dmantipov@yandex.ru> > Cc: Johannes Berg <johannes.berg@intel.com> > Cc: zuoqilin <zuoqilin@yulong.com> > Cc: Ruan Jinjie <ruanjinjie@huawei.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr> > Cc: Gustavo A. R. Silva <gustavoars@kernel.org> > Cc: linux-wireless@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org>
TLV and one-element arrays are always tricky to transform (into flex arrays), but (unless I'm missing something that the maintainers might point out) this looks good to me.
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Thanks! -- Gustavo
> --- > v3: catch two more cases of changed sizeof (gustavo) > v2: https://lore.kernel.org/linux-hardening/20240206183857.it.362-kees@kernel.org/ > v1: https://lore.kernel.org/linux-hardening/20240206163501.work.158-kees@kernel.org/ > --- > drivers/net/wireless/marvell/mwifiex/11n.c | 12 +++++------- > drivers/net/wireless/marvell/mwifiex/fw.h | 2 +- > drivers/net/wireless/marvell/mwifiex/scan.c | 14 ++++++-------- > 3 files changed, 12 insertions(+), 16 deletions(-) > > diff --git a/drivers/net/wireless/marvell/mwifiex/11n.c b/drivers/net/wireless/marvell/mwifiex/11n.c > index 90e401100898..c0c635e74bc5 100644 > --- a/drivers/net/wireless/marvell/mwifiex/11n.c > +++ b/drivers/net/wireless/marvell/mwifiex/11n.c > @@ -392,12 +392,10 @@ mwifiex_cmd_append_11n_tlv(struct mwifiex_private *priv, > > chan_list = > (struct mwifiex_ie_types_chan_list_param_set *) *buffer; > - memset(chan_list, 0, > - sizeof(struct mwifiex_ie_types_chan_list_param_set)); > + memset(chan_list, 0, struct_size(chan_list, chan_scan_param, 1)); > chan_list->header.type = cpu_to_le16(TLV_TYPE_CHANLIST); > - chan_list->header.len = cpu_to_le16( > - sizeof(struct mwifiex_ie_types_chan_list_param_set) - > - sizeof(struct mwifiex_ie_types_header)); > + chan_list->header.len = > + cpu_to_le16(sizeof(struct mwifiex_chan_scan_param_set)); > chan_list->chan_scan_param[0].chan_number = > bss_desc->bcn_ht_oper->primary_chan; > chan_list->chan_scan_param[0].radio_type = > @@ -411,8 +409,8 @@ mwifiex_cmd_append_11n_tlv(struct mwifiex_private *priv, > (bss_desc->bcn_ht_oper->ht_param & > IEEE80211_HT_PARAM_CHA_SEC_OFFSET)); > > - *buffer += sizeof(struct mwifiex_ie_types_chan_list_param_set); > - ret_len += sizeof(struct mwifiex_ie_types_chan_list_param_set); > + *buffer += struct_size(chan_list, chan_scan_param, 1); > + ret_len += struct_size(chan_list, chan_scan_param, 1); > } > > if (bss_desc->bcn_bss_co_2040) { > diff --git a/drivers/net/wireless/marvell/mwifiex/fw.h b/drivers/net/wireless/marvell/mwifiex/fw.h > index 62f3c9a52a1d..3adc447b715f 100644 > --- a/drivers/net/wireless/marvell/mwifiex/fw.h > +++ b/drivers/net/wireless/marvell/mwifiex/fw.h > @@ -770,7 +770,7 @@ struct mwifiex_chan_scan_param_set { > > struct mwifiex_ie_types_chan_list_param_set { > struct mwifiex_ie_types_header header; > - struct mwifiex_chan_scan_param_set chan_scan_param[1]; > + struct mwifiex_chan_scan_param_set chan_scan_param[]; > } __packed; > > struct mwifiex_ie_types_rxba_sync { > diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c > index a2ddac363b10..0326b121747c 100644 > --- a/drivers/net/wireless/marvell/mwifiex/scan.c > +++ b/drivers/net/wireless/marvell/mwifiex/scan.c > @@ -664,15 +664,14 @@ mwifiex_scan_channel_list(struct mwifiex_private *priv, > > /* Copy the current channel TLV to the command being > prepared */ > - memcpy(chan_tlv_out->chan_scan_param + tlv_idx, > + memcpy(&chan_tlv_out->chan_scan_param[tlv_idx], > tmp_chan_list, > - sizeof(chan_tlv_out->chan_scan_param)); > + sizeof(*chan_tlv_out->chan_scan_param)); > > /* Increment the TLV header length by the size > appended */ > le16_unaligned_add_cpu(&chan_tlv_out->header.len, > - sizeof( > - chan_tlv_out->chan_scan_param)); > + sizeof(*chan_tlv_out->chan_scan_param)); > > /* > * The tlv buffer length is set to the number of bytes > @@ -2369,12 +2368,11 @@ int mwifiex_cmd_802_11_bg_scan_config(struct mwifiex_private *priv, > chan_idx < MWIFIEX_BG_SCAN_CHAN_MAX && > bgscan_cfg_in->chan_list[chan_idx].chan_number; > chan_idx++) { > - temp_chan = chan_list_tlv->chan_scan_param + chan_idx; > + temp_chan = &chan_list_tlv->chan_scan_param[chan_idx]; > > /* Increment the TLV header length by size appended */ > le16_unaligned_add_cpu(&chan_list_tlv->header.len, > - sizeof( > - chan_list_tlv->chan_scan_param)); > + sizeof(*chan_list_tlv->chan_scan_param)); > > temp_chan->chan_number = > bgscan_cfg_in->chan_list[chan_idx].chan_number; > @@ -2413,7 +2411,7 @@ int mwifiex_cmd_802_11_bg_scan_config(struct mwifiex_private *priv, > chan_scan_param); > le16_unaligned_add_cpu(&chan_list_tlv->header.len, > chan_num * > - sizeof(chan_list_tlv->chan_scan_param[0])); > + sizeof(*chan_list_tlv->chan_scan_param)); > } > > tlv_pos += (sizeof(chan_list_tlv->header)
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