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Bluetooth: Host: Add legacy pairing test config #99742

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Bluetooth: Host: Add legacy pairing test config #99742

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9 changes: 9 additions & 0 deletions subsys/bluetooth/host/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -1163,6 +1163,15 @@ config BT_CONN_DISABLE_SECURITY
WARNING: This option enables anyone to snoop on-air traffic.
Use of this feature in production is strongly discouraged.

config BT_SMP_LEGACY_PAIR_ONLY
bool "Force legacy pairing"
depends on BT_TESTING
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@Thalley Thalley Nov 20, 2025

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Is it not allowed to only support legacy pairing in recent version of the core spec?

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@HaavardRei HaavardRei Nov 21, 2025

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It's allowed, but since Zephyr 3.0 the use of legacy pairing has been discouraged for being less/not secure, so I didn't want this Kconfig to imply otherwise. Zephyr-devices support legacy pairing with devices that do not support secure connections, but since Zephyr-devices do support it they will always default to this (and thus this config is needed to force it).

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@Thalley Thalley Nov 21, 2025

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I'm wondering if we should allow setting this without BT_TESTING, but treat it as a warning for the above reasons. That would be similar to how we treat e.g. BT_USE_DEBUG_KEYS, where we have both Kconfig and CMake warnings if it's enabled.

Alternatively we should consider adding the same depends on BT_TESTING for things like BT_USE_DEBUG_KEYS.

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@HaavardRei HaavardRei Nov 21, 2025

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Both suggestions are fine by me, do you have any thoughts @jhedberg?

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@jhedberg jhedberg Nov 21, 2025

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I think depends on BT_TESTING is the right way. BT_USE_DEBUG_KEYS should have it as well.

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@Thalley Thalley Nov 21, 2025

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@jhedberg Should we apply depends on BT_TESTING for all the other similar configs? And then if we do, should we remove the warning for them as well, and add/keep only a warning for BT_TESTING?

depends on !(BT_SMP_SC_PAIR_ONLY || BT_SMP_SC_ONLY)
help
This option enforces legacy pairing. This is required for testing
legacy pairing between two Zephyr Bluetooth devices, as without this
option the devices will default to using Secure Connections pairing.

rsource "./classic/Kconfig"

config BT_HCI_VS_EVT_USER
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11 changes: 6 additions & 5 deletions subsys/bluetooth/host/smp.c
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Expand Up @@ -93,21 +93,21 @@
#if defined(CONFIG_BT_CLASSIC)

#define BT_SMP_AUTH_MASK_SC 0x2f
#if defined(CONFIG_BT_SMP_OOB_LEGACY_PAIR_ONLY)
#if defined(CONFIG_BT_SMP_OOB_LEGACY_PAIR_ONLY) || defined(CONFIG_BT_SMP_LEGACY_PAIR_ONLY)
#define BT_SMP_AUTH_DEFAULT (BT_SMP_AUTH_BONDING_FLAGS | BT_SMP_AUTH_CT2)
#else
#define BT_SMP_AUTH_DEFAULT (BT_SMP_AUTH_BONDING_FLAGS | BT_SMP_AUTH_CT2 |\
BT_SMP_AUTH_SC)
#endif /* CONFIG_BT_SMP_OOB_LEGACY_PAIR_ONLY */
#endif /* CONFIG_BT_SMP_OOB_LEGACY_PAIR_ONLY || CONFIG_BT_SMP_LEGACY_PAIR_ONLY */

#else

#define BT_SMP_AUTH_MASK_SC 0x0f
#if defined(CONFIG_BT_SMP_OOB_LEGACY_PAIR_ONLY)
#if defined(CONFIG_BT_SMP_OOB_LEGACY_PAIR_ONLY) || defined(CONFIG_BT_SMP_LEGACY_PAIR_ONLY)
#define BT_SMP_AUTH_DEFAULT (BT_SMP_AUTH_BONDING_FLAGS)
#else
#define BT_SMP_AUTH_DEFAULT (BT_SMP_AUTH_BONDING_FLAGS | BT_SMP_AUTH_SC)
#endif /* CONFIG_BT_SMP_OOB_LEGACY_PAIR_ONLY */
#endif /* CONFIG_BT_SMP_OOB_LEGACY_PAIR_ONLY || CONFIG_BT_SMP_LEGACY_PAIR_ONLY */

#endif /* CONFIG_BT_CLASSIC */

Expand Down Expand Up @@ -322,7 +322,8 @@

static bool le_sc_supported(void)
{
if (IS_ENABLED(CONFIG_BT_SMP_OOB_LEGACY_PAIR_ONLY)) {
if (IS_ENABLED(CONFIG_BT_SMP_OOB_LEGACY_PAIR_ONLY) ||

Check warning on line 325 in subsys/bluetooth/host/smp.c

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SonarQubeCloud / SonarCloud Code Analysis

Identical sub-expressions on both sides of operator "||". 


See more on https://sonarcloud.io/project/issues?id=zephyrproject-rtos_zephyr&issues=AZqhYqtlO7-2aqJKN4x6&open=AZqhYqtlO7-2aqJKN4x6&pullRequest=99742
IS_ENABLED(CONFIG_BT_SMP_LEGACY_PAIR_ONLY)) {
return false;
}

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