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fix(tee): reject invalid session in invoke to close NULL-deref DoS (#247) #248

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Merged
tdrozdovsky merged 1 commit into from
Jul 27, 2026
Merged

fix(tee): reject invalid session in invoke to close NULL-deref DoS (#247) #248

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13 changes: 13 additions & 0 deletions tee/kernel/entry_std.c
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Original file line number Diff line number Diff line change
Expand Up @@ -406,6 +406,19 @@ TEEC_Result tee_ioctl_invoke(/*ctx,*/ struct tee_ioctl_buf_data *buf_data)
if (res != TEE_SUCCESS)
goto out;

if (!sess) {
/*
* A Non-Secure caller can supply an invalid/zero/stale session id.
* find_session() then returns NULL and, since the guards in
* tee_ta_invoke_command() are disabled, the secure world would
* dereference NULL (sess->ctx->...) -> secure-world crash/DoS.
* Reject before invoking. Placed after copy_in_params so a malformed
* request still gets the more specific error from parameter validation.
*/
res = TEEC_ERROR_BAD_PARAMETERS;
goto out;
}

res = tee_ta_invoke_command(&err, sess, arg->func, &param);

copy_out_param(&param, arg->num_params, arg->params, saved_attr);
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9 changes: 9 additions & 0 deletions tee/kernel/tee_ta_manager.c
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Expand Up @@ -637,6 +637,15 @@ TEE_Result tee_ta_invoke_command(TEE_ErrorOrigin *err,
{
TEE_Result res;

/*
* Defense in depth: never dereference a NULL session. Callers (e.g. the
* Non-Secure ioctl veneer) obtain sess from tee_ta_get_session(), which
* returns NULL for an unknown session id; without this guard the line
* below would fault in the secure world.
*/
if (!sess)
return TEE_ERROR_BAD_PARAMETERS;

// if (check_client(sess, clnt_id) != TEE_SUCCESS)
// return TEE_ERROR_BAD_PARAMETERS; /* intentional generic error */
//
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