Re: [PATCH] KEYS: trusted: fix crash when TPM/TEE are built as module

On Sun, Feb 6, 2022 at 2:36 AM Ahmad Fatoum [off-list ref] wrote:

Hello Tong,

On 04.02.22 21:03, Tong Zhang wrote:

quoted

when TCG_TPM and TEE are built as module, trusted_key_sources will be an
empty array, loading it won't do what it is supposed to do and unloading
it will cause kernel crash.

Jarkko reported picking up an equivalent fix two months ago:
https://lkml.kernel.org/keyrings/YadRAWbl2aiapf8l@iki.fi/

But it seems to have never made it to Linus.

Cheers,
Ahmad

quoted

To reproduce:
$ modprobe trusted
$ modprobe -r trusted

[  173.749423] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[  173.755268] Backtrace:
[  173.755378]  cleanup_trusted [trusted] from sys_delete_module+0x15c/0x22c
[  173.755589]  sys_delete_module from ret_fast_syscall+0x0/0x1c

To fix this issue, we also need to check CONFIG_TCG_TPM_MODULE and
CONFIG_TEE_MODULE.

Fixes: 5d0682be3189 ("KEYS: trusted: Add generic trusted keys framework")
Signed-off-by: Tong Zhang <redacted>
---
 security/keys/trusted-keys/trusted_core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
index d5c891d8d353..b3a3b2f2d4a4 100644
--- a/security/keys/trusted-keys/trusted_core.c
+++ b/security/keys/trusted-keys/trusted_core.c

@@ -27,10 +27,10 @@ module_param_named(source, trusted_key_source, charp, 0);
 MODULE_PARM_DESC(source, "Select trusted keys source (tpm or tee)");

 static const struct trusted_key_source trusted_key_sources[] = {
-#if defined(CONFIG_TCG_TPM)
+#if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
      { "tpm", &trusted_key_tpm_ops },
 #endif
-#if defined(CONFIG_TEE)
+#if defined(CONFIG_TEE) || defined(CONFIG_TEE_MODULE)
      { "tee", &trusted_key_tee_ops },
 #endif
 };

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Hi Ahmad,
Thanks for letting me know.
That fix looks good to me.
- Tong