[Deepin-Kernel-SIG] [Upstream] [linux 6.6-y] Sync some mac80211 bugfix from mainline

[opsiff]

Commit(3):
wifi: mac80211: improve CSA/ECSA connection refusal
wifi: cfg80211: detect stuck ECSA element in probe resp
wifi: mac80211: don't connect to an AP while it's in a CSA process

Summary by Sourcery

This pull request improves the mac80211 driver's handling of Channel Switch Announcements (CSA) and Extended Channel Switch Announcements (ECSA). It prevents the driver from attempting to connect to an AP while it is in a CSA process and detects stuck ECSA elements in probe responses.

Bug Fixes:

• Fixes an issue where the driver could attempt to connect to an AP while it is in the middle of a Channel Switch Announcement (CSA) process, which could lead to connection failures or instability.
• Improves the reliability of CSA/ECSA handling by detecting and ignoring 'stuck' ECSA elements in probe responses, preventing the driver from misinterpreting outdated channel switch information.

Enhancements:

• Improves the robustness of Wi-Fi connections by preventing connections to APs during CSA, ensuring a smoother transition during channel switches.

[sourcery-ai]

Reviewer's Guide by Sourcery

This pull request enhances Wi-Fi connection stability by addressing issues related to Channel Switch Announcements (CSA) and Extended Channel Switch Announcements (ECSA). It prevents connections to APs during CSA processes and improves detection of stuck ECSA elements.

Sequence diagram for rejecting authentication during CSA process

sequenceDiagram
    participant STA as Station
    participant MGD as Management Daemon
    participant AP as Access Point

    STA->>MGD: Auth Request
    MGD->>MGD: ieee80211_mgd_csa_in_process(req->bss)
    alt AP is in CSA process
        MGD-->>STA: Auth Reject (-EINVAL)
    else AP is not in CSA process
        MGD->>AP: Auth Request
        AP-->>MGD: Auth Response
        MGD-->>STA: Auth Confirm
    end

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Sequence diagram for rejecting association during CSA process

sequenceDiagram
    participant STA as Station
    participant MGD as Management Daemon
    participant AP as Access Point

    STA->>MGD: Assoc Request
    MGD->>MGD: ieee80211_mgd_csa_in_process(cbss)
    alt AP is in CSA process
        MGD-->>STA: Assoc Reject (-EINVAL)
    else AP is not in CSA process
        MGD->>AP: Assoc Request
        AP-->>MGD: Assoc Response
        MGD-->>STA: Assoc Confirm
    end

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Updated class diagram for cfg80211_bss

classDiagram
    class cfg80211_bss {
        +u8 chains
        +s8 chain_signal[IEEE80211_MAX_CHAINS]
        +u8 proberesp_ecsa_stuck
        +u8 bssid_index
        +u8 max_bssid_indicator
    }
    note for cfg80211_bss "Added proberesp_ecsa_stuck field"

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File-Level Changes

Change	Details	Files
Implements a mechanism to detect and ignore 'stuck' Extended Channel Switch Announcement (ECSA) elements in probe responses.	Adds a proberesp_ecsa_stuck flag to the cfg80211_bss struct to indicate a stuck ECSA element. Introduces cfg80211_check_stuck_ecsa to detect stuck ECSA elements by comparing consecutive probe responses. Sets the proberesp_ecsa_stuck flag if the ECSA element remains unchanged for more than one second. The driver will ignore the ECSA element if the proberesp_ecsa_stuck flag is set.	net/wireless/scan.c include/net/cfg80211.h
Prevents the driver from attempting to connect to an AP while it is in the middle of a Channel Switch Announcement (CSA) or Extended Channel Switch Announcement (ECSA) process.	Introduces the ieee80211_mgd_csa_present function to check for the presence of CSA/ECSA elements in beacon or probe response IEs. Introduces the ieee80211_mgd_csa_in_process function to determine if an AP is currently in a CSA process. The driver will now refuse authentication or association with an AP if it detects that the AP is in a CSA process.	net/mac80211/mlme.c

---

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[sourcery-ai]

Hey @opsiff - I've reviewed your changes - here's some feedback:

Overall Comments:

• Consider adding a comment explaining why ieee80211_mgd_csa_present ignores ECSA elements when ignore_ecsa is true.
• It might be helpful to add a comment to cfg80211_check_stuck_ecsa explaining why the function returns early if known->pub.proberesp_ecsa_stuck is already set.

Here's what I looked at during the review

• 🟢 General issues: all looks good
• 🟢 Security: all looks good
• 🟢 Testing: all looks good
• 🟡 Complexity: 1 issue found
• 🟢 Documentation: all looks good

---

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[sourcery-ai]

issue (complexity): Consider refactoring the CSA/ECSA validation checks into a helper function to reduce code duplication.

Consider removing duplicate CSA/ECSA validation code by refactoring the common checks into a helper function. For example, you could create a helper that validates an element’s data and returns whether that element should be ignored. Then call that helper for both CSA and ECSA. For instance:

---
static bool validate_csa_element(const struct element *elem, size_t expected_len,
				 u8 cur_channel)
{
	void *data;
	/* Check element exists and is the expected length */
	if (!elem || elem->datalen != expected_len)
		return false;

	/* Common parsing and validation for CSA element */
	data = (void *)elem->data;
	/* Replace `struct ieee80211_channel_sw_ie` with appropriate type for this element */
	if (((struct ieee80211_channel_sw_ie *)data)->count == 0 ||
	    (!((struct ieee80211_channel_sw_ie *)data)->mode &&
	     ((struct ieee80211_channel_sw_ie *)data)->new_ch_num == cur_channel))
		return false;

	return true;
}
---

You can then simplify `ieee80211_mgd_csa_present()` as follows (similarly for the ECSA path, using the correct type and expected length):

---
static bool ieee80211_mgd_csa_present(struct ieee80211_sub_if_data *sdata,
				      const struct cfg80211_bss_ies *ies,
				      u8 cur_channel, bool ignore_ecsa)
{
	bool has_csa = false, has_ecsa = false;
	const struct element *csa_elem, *ecsa_elem;

	if (!ies)
		return false;

	csa_elem = cfg80211_find_elem(WLAN_EID_CHANNEL_SWITCH, ies->data, ies->len);
	has_csa = validate_csa_element(csa_elem, sizeof(struct ieee80211_channel_sw_ie), cur_channel);

	ecsa_elem = cfg80211_find_elem(WLAN_EID_EXT_CHANSWITCH_ANN, ies->data, ies->len);
	has_ecsa = validate_csa_element(ecsa_elem, sizeof(struct ieee80211_ext_chansw_ie), cur_channel);

	if (ignore_ecsa && has_ecsa) {
		sdata_info(sdata,
			   "Ignoring ECSA in probe response - was considered stuck!\n");
		return has_csa;
	}

	return has_csa || has_ecsa;
}
---

Additionally, in `ieee80211_mgd_csa_in_process()`, you can combine the conditions without using goto:

---
static bool ieee80211_mgd_csa_in_process(struct ieee80211_sub_if_data *sdata,
					 struct cfg80211_bss *bss)
{
	u8 cur_channel = ieee80211_frequency_to_channel(bss->channel->center_freq);
	bool in_process;

	rcu_read_lock();
	in_process = ieee80211_mgd_csa_present(sdata, rcu_dereference(bss->beacon_ies),
						 cur_channel, false) ||
		     ieee80211_mgd_csa_present(sdata, rcu_dereference(bss->proberesp_ies),
						 cur_channel, bss->proberesp_ecsa_stuck);
	rcu_read_unlock();
	return in_process;
}
---

By factoring out the repetitive logic and avoiding goto in favor of clear boolean expressions, the complexity is reduced while the functionality remains intact.

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: sourcery-ai[bot]
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[opsiff]

/ok-to-test